We've just posted a new info sheet about Capnocytophaga. One member of this bacterial group in particular, Capnocytophaga canimorsus, makes the news periodically because it can cause devastating infection in some individuals, like the Ottawa woman who lost three limbs after one of her own dogs accidentally bit her. This kind of severe infection, which is also sometimes called dog bite septicemia, is actually quite rare, but people with certain risk factors such as diabetes, alcoholism, and particularly lack of a functional spleen are at much higher risk. The bacterium very commonly lives in the mouths of dogs and cats, and is considered a part of the normal oral microflora in these animals. People are therefore commonly exposed to Capnocytophaga, yet infection is rare, but because it can be so catastrophic it's important to know the facts, especially if you or someone you know may be at higher risk.
You can read more about Capnocytophaga on the new info sheet, which you can find along with all our other info sheets on the Worms & Germs Resources - Pets page. You can also read about Capnocytophaga in the posts in our archives.
One of our most frequent pieces of advice on W&GB when it comes to kids is to always make sure they are supervised when they are around pets. This is important for at least two major reasons, one being avoiding potential high-risk contacts when it comes to infectious disease transmission (e.g. face-to-mouth, hand-to-bum), and the other being reducing the risk of injury (and subsequent infection) from bites and scratches. Children often don't know or aren't aware of the signs that a pet is stressed or uncomfortable, essentially forcing the pet to take progressively more drastic measures to get its message across, potentially ending in a snap or a bite. The problem is a lot of the time the supervising adult also doesn't know these signs, and thus many a bite or scratch may happen even when a parent is watching carefully from only a few feet away.
Yesterday I came across an excellent post on this very topic on another blog written by Robin Bennett, a certified professional dog trainer (CPDT-KA) in Virginia. Her post was very aptly entitled "Why Supervising Dogs and Kids Doesn't Work." Click on the title to see the entire post, but here are a few of the great points she makes:
- Watch for inappropriate child behaviour. In Robin's words, "Don’t marvel that your dog has the patience of Job if he is willing to tolerate [being poked, prodded, yanked, pulled, pushed, etc]. And please don’t videotape it for YouTube! Be thankful your dog has good bite inhibition and intervene before it’s too late."
- Intervene early. If the dog loses that loose, wiggly body posture and starts to stiffen up, don't wait until the animal has to escalate its message to growling or snapping to step in.
- Support the dog's good choices. If the dog chooses to move away from a child because it is uncomfortable, support that choice and don't let the child continue to follow the animal. If the pet can't get away, it may scratch or bite to try to make the child go away instead. Don't force the dog to make that choice. (This applies equally to cats or any other pet!)
It's very important for pet owners to educate themselves about basic pet behaviour, whether they have dogs, cats or other animals, and to teach that same information to their children. Another great program that teaches kids how to behave around dogs, and unfamiliar dogs in particular, is the "Be a tree" program, details of which can be found on the Doggone Safe dog bite prevention website.
A colleague recently let me know about an article in the journal Infection Ecology and Epidemiology entitled “Human wound infectious caused by Nesseria animaloris and Neisseria zoodegmatis, former CDC Group EF-4a and EF-4b" (Heydecke et al 2013).
These are new bugs to me…
The article outlines an effort to characterize these bacteria from people with wound infections, most from dog bites. Thirteen bacterial isolates were studied - 11 were determined to be N. animaloris and 2 the related bacterium N. zoodegmatis. The authors concluded that localized infections occur most often, but severe complications can sometimes develop and that recovery is often slow (probably because of suboptimal treatment).
The true role of these bacteria in disease is unclear, since they might be missed by diagnostic labs or misinterpreted as being contaminants (and therefore not tested further or reported). These bugs tend to be resistant to quite a few antibiotics, so identifying them promptly is important to get the right treatment started.
There’s never a dull moment in infectious diseases. We’re constantly hearing about new pathogens. Sometimes, it’s because people just rename bugs about which we already know a lot. Sometimes, it’s because we realize that what we thought was one bacterial species is actually more than one. Sometimes, it’s because we realize that something we’ve dismissed as innocuous is truly a potential problem (so we start paying attention to it). Finally, sometimes truly new microorganisms are identified. With bacteria, the latter usually happens when someone first figures out how to identify an organism that’s been around for a while, but true emergence of new microorganisms can occur.
Anyway, whenever a new bug is found, it’s important to figure out how relevant it is. In this case, in the end, we’re still left with the main point being that the mouths of our domestic pets are cesspools of bacterial badness. Most often, our skin and immune system are able to prevent this from being a problem. However, when bites occur (or in other situations, such as licking wounds or when people have compromised immune systems), the potential for disease increases. Yet, it doesn’t really matter what the bug is - the key prevention points are the same:
- Reduce the risk of bites by good animal training, good animal handling and common sense.
- Promptly and thoroughly wash any bite wounds.
- If you have a compromised immune system, make sure you talk to your physician about any risks of pet contact and what to do in the event of a bite.
This report doesn’t mean that dogs are any higher risk to people than they were before. It just means we have a new name for a risk that’s been present for a while.
ProMed-mail usually posts a monthly recap of rabies cases in the US. The most recent one (like most of them) doesn't have anything too astounding, but it provides some good reminders.
Skunk attacks baby
A five-month-old baby that was outside in a car seat was bitten in the face several times by a skunk. The skunk was killed and tested positive for rabies. This is a high risk situation because it involves a young child and bites to the face. Because of that, the incubation period would potentially be very short so prompt treatment of the baby would be needed (and presumably post-exposure treatment was started right away).
Rabid family dog attacks
Five people were bitten by their pet dog, which was subsequently identified as being rabid. This should be a reminder that rabies exposure is still a concern with pets, that pets should be vaccinated, and that rabies exposure must be considered after any bite.
Fox + bite + electric hedge clippers = ...
A Virginia man was bitten by a fox, and he then killed the fox with hedge clippers (probably not a pretty sight). The bite did not break the skin (although the man did pass out afterward... not sure whether that was from fear of the bite or the aftermath). Anyway, the fox is only being reported as "presumed" rabid. Given the time frame of the encounter and the press release, I would have thought they'd know the rabies status of the animal, if it was tested. In the absence of knowing that the fox was not rabid, they'd have to assume that it was and take appropriate measures. Since the bite didn't break the skin, the bite shouldn't be considered rabies exposure; however, depending on how gory the subsequent fox-clipping was, there might have been exposure to infectious tissues by other means, and post-exposure treatment might have been indicated anyway.
Calf bites, animal health personnel screw up
Rhode Island health officials are trying to track down anyone that might have been exposed to a calf that lived next door to a popular ice cream shop. The calf bit someone and was quarantined. However, it died the next day and in a pretty major screw-up, local animal health officials didn't notify the state until 3 days later. By that time, the calf's body was too decomposed to be tested for rabies. So, it must be assumed that the calf was rabid.
A few take home messages:
- Rabies is still around... think about it.
- Vaccinate your pets.
- Avoid contact with wildlife, and if wildlife is behaving abnormally (e.g. attacking), rabies must considered.
- Make sure all bites from mammals are reported so that the need (if any) for rabies post-exposure treatment can be determined.
- Hedge clippers are not the best euthanasia tools.
Dogs have had some bad PR lately because of some high-profile bites and bite infections in people. So, in the spirit of fairness, I’ll write about a dog as a victim of an attack… from a cat.
Any infection characterized as "necrotizing" is bad. Necrotizing essentially means "dying," and any time you put "dying" in front of the name of a tissue or body part, you can assume the condition is pretty high on the "badness" scale.
In this case, the dog was a three-year-old Whippet that was bitten on the chest by a neighbour’s cat. The dog developed necrotizing cellulitis due to Pasteurella multocida, a bacterium that is commonly found in the mouths of cats, and one that not uncommonly causes cat bite infections in people as well. Within 24 hours of the incident, there was redness, swelling and pain over the area of the bite. The skin lesion progressed rapidly, with death of the skin over the affected area and development of large, deep skin ulcers, similar to what can happen in people with this kind of infection. Fortunately, the dog was successfully treated with intravenous antibiotics and survived.
Why did this dog develop necrotizing disease?
The reason one infection with P. multocida becomes necrotizing while another infection with the same bacterium does not is unknown The same is true for most cases of necrotizing fasciitis (aka flesh eating disease) in people, which is usually caused by Group A Streptococcus or by Staphylococcus aureus. While saying it's "bad luck" is highly unscientific, it’s about all we can say in most cases, since there are often no obvious factors that would predispose the affected individual to severe disease, and the bacterial strains that cause necrotizing infection are usually the same as those that cause mild disease and that are found in healthy individuals. So the "bad luck" explanation is about all we have to offer at this point.
It's maybe a sad statement that reading about someone whose diseased toes were gnawed off by their dog doesn't shock me anymore. It's not an everyday event but it's far from rare. An Indiana man learned about this the hard way when he woke up thinking his dog was licking his toes, when in fact, the dog had eaten them.
As is typical in cases like this, the person is a diabetic and had a foot infection, which contributed to the dog being attracted to the toes and the person not feeling the midnight snacking. Presumably, the person will be fine with some wound care and antibiotics. In fact, the dog may have just altered the manner of amputation if the toes were that severely affected. They may have been coming off one way on the other in the near future, but this is still not the desired approach.
A couple of questions come up sometimes in cases like this.
Is the man at risk of any infections from the dog?
- Certainly, there are concerns. This should be treated just like a bite since there was obviously contact between dog saliva and broken skin. Antibiotics were presumably already being used because of the toe infection, so that might have been enough, but antibiotic treatment would be needed in a situation like this given the type of exposure and the person's compromised state.
- Rabies is unlikely but it still has to be considered. This is just like a bite, so a 10 day observation period of the dog would be indicated. There's almost zero risk of rabies here, but when we're talking about rabies, "almost" isn't good enough.
Is the dog at risk of catching anything from the owner?
- This is perhaps the more likely of the two concerns. The dog was licking and eating infected tissue. Many of the bacteria that cause this type of infection can also infect dogs. The odds of the dog developing disease from this are pretty low. It's more likely the dog would become a carrier of the bacterium for a while (e.g. in its mouth, nose, or intestinal tract). If the dog is otherwise healthy, it's probably not going to suffer any consequences, but knowing what bacterium was causing the toe infection would help with that risk assessment.
While dogs amputating toes is rare, it's surprising how often I hear about people who let their dogs lick diabetic ulcers. As well, I've heard of people who have looked down and realized their dog or cat was gnawing on their toes (not amputating - at least not yet - but chewing away nonetheless). Usually, these are diabetics. Usually, nothing bad will happen. However, a dog's mouth contains many different bacteria that can cause severe illness given the right situation, and chewing on a toe of a diabetic patient in particular would fit into that "in the right situation" category.
I've been bitten lots of times, some on the job (including the last dog I saw when I was in general practice) and some off (including a dog down the road a couple of years ago). Fortunately, I haven't suffered any serious consequences. That's what happens most of the time. However, bad things can and do occur after bites.
A paper in BMJ Case Reports (Tumram et al 2012) describes a rather unusual and unfortunate situation. It's about a fatal infection in a 55-year-old Indian woman who was bitten by a mongoose. She was bitten (unprovoked, it seems) on the leg by the mongoose while washing dishes. She went to the hospital a couple of hours later because of pain and swelling in her leg. It's not clear what happened there, but she went back to hospital the next day, and then received antibiotics. However, that same day, she suffered cardiac arrest (a heart attack) and died a few days later. The bacterium Streptococcus pyogenes (Group A Streptococcus) was isolated from some lesions on her legs, leading to a suspicion that she developed a severe and rapidly progressive infection from the mongoose bite.
Various aspects of this case are unusual. Fatal bite infections occur, but they are rare. Involvement of streptococci is rarer still.
Why did this woman develop a fatal infection, especially when she sought prompt medical care? It's hard to say, and there is a "bad luck" component of infectious diseases. She had diabetes and high blood pressure, which probably increased her susceptibility to infection (but lots of other people who get bitten also have these conditions and suffer no consequences). It doesn't appear that she received antibiotics when she went to the hospital originally, but a bite over the leg isn't one that would always be treated prophylactically with antibiotics.
Why did the mongoose bite? That's another good question. Unless you're a snake, mongooses are typically not aggressive.
Where did the bacteria come from? We don't know much about the oral bacterial population of mongooses, but Streptococcus pyogenes is a human-associated bacterium. It's rarely found in animals and I suspect that the strep didn't come from the mongoose. Rather, it was probably already on the woman's skin and introduced into her body by the bite, or she contaminated the wound after being bitten. It's just a guess, and it doesn't change anything, but it makes sense.
This report shouldn't make people freak out over a bite. However, it should serve as a reminder that bad things can happen. More information about dealing with bites can be found on the Worms & Germs Resources - Pets page.
Image: Dwarf mongoose (Helogale parvula) in Korkeasaari zoo (photo credit: Miika Silfverberg, click image for source)
It's not hard to find news articles about animal bites. That's because they are very common, sometimes incite controversy (e.g. to euthanize the offending animal or not) and occasionally cause severe injury or death.
Here's a sampling of some recent reports:
- The University of Arizona Medical Center is reporting a steady increase in dog bites, with an almost doubling of bite numbers between 2008 and 2012. Three-hundred and twenty-eight (328) people were admitted with bites last year, including both children and adults. Most were bitten on the hands and fingers, and most were bitten by their own dogs. There were no deaths reported in 2012, but there was one in 2011, a man that was bitten in the neck and arm by his own pit bull cross.
- Sixty-three dog bite deaths were reported in Mumbai, India, over the past 5 years, out of a total of at least 90 000 people who are bitten annually.
- A Stoney Creek, Ontario mother is lobbying to have her neighbour's two German shepherds euthanized after they attached her 10-year-old son. The dogs were on leashes and being held by a friend of the owner's 14-year-old son when "The dogs became startled" and the boy was bitten on the arm and face. The dogs' owner argues that only one dog was involved, but figuring that out will be next to impossible. This raises a few different issues. One is the fact that a child, and not even a child of the owner, was responsible for the control of two large dogs in a public place. Another is what lead to the bite. The owner accuses the boy of taunting the dogs in the past, but even if that were true, previous taunting (what did he do? accuse the dogs of having a chihuahua for a mother?) isn't an excuse for biting.
While we often focus on dog bites, pretty much any animal with a mouth can bite. Records from a New South Wales, Australia, ambulance service reveal some more unusual calls for help in response to animal interactions. These include:
- A call because of a "deep bite on the hand" with "serious bleeding" after a woman was bitten by a Guinea pig. They were also called for a Guinea pig bite to a 4-year-old boy. The fact that Guinea pigs would bite isn't surprising, but the fact that the bite would lead to an ambulance call is.
- A call for a cat bite that severed an unnamed artery of an 80-year-old man. Hopefully it was a small artery.
- While not a bite (although cattle can bite), ambulances were called when a cow hit a 83-year-old man in the stomach, lifting him 3 feet in the air, and when a water buffalo tossed another man.
- Other animal associated calls included incidents caused by critters including a blue-ringed octopus, a catfish (would love to have the story about that one) and a goanna (a type of Australian monitor lizard - had to look that one up).
- And (not surprisingly, for Australia) there were shark bites, including a spear fisher who was "nudged" by a grey nurse shark attracted to the fish he had caught, and a more serious attack by a bull shark that resulted in loss of a finger and a serious leg laceration.
- Snake and spider bites weren't even listed in the report for some reason.
Understanding why bites occur is important to preventing them, and it's different in different areas. In North America, where most dog bites are from family pets, better training of the dog and people in the household is critical. In a place like Mumbai, where there are tens of thousands of stray dogs living in close confines with people and where many bites are from strays, a different approach is needed. Bites from pocket pets usually result from improper handling or trying to break up a fight. Shark bites are also another story. Ultimately, a lot of prevention is common sense, which unfortunately is not always that common.
ProMed Mail's monthly US rabies update often contains some interesting cases, and the last one is no exception.
A llama in Georgia became aggressive, started biting itself and was spitting at one of its caretakers. A spitting llama certainly doesn't mean rabies (I have dodged enough llama spitballs to know that) but any sudden change in behaviour, especially with aggression, should raise some major red flags. Here, the llama was diagnosed as rabid and the person that was spat on is receiving post-exposure treatment.
A bobcat attacked a man and boy in Massachusetts, and not surprisingly, was diagnosed with rabies. In this case, the bobcat pounced on the man, bit his face, clawed his back and held him in something akin to a bear hug, before moving on to the man's nephew. Wild animals don't typically attack except under extenuating circumstances (e.g. being cornered, protecting offspring), so this type of event should be considered a rabies exposure until proven otherwise. The man shot the bobcat and it was confirmed as rabid.
In an all-too-common scenario, a family that took in a stray kitten ended up needing post-exposure treatment because the kitten was rabid. They found the sick kitten and tried to nurse it back to health, but it died the next day. Fortunately, animal control arranged for rabies testing, something that could have easily been overlooked if no one thought about rabies and just assumed the kitten was sick for some other reason. Two dogs in the household were also considered exposed, but fortunately had been properly vaccinated, so typical recommendations would be for a 45-day observation period versus 6 months strict quarantine or immediate euthanasia had they not been vaccinated.
In a similar scenario, two women are undergoing post-exposure treatment after being bitten by a stray kitten they were trying to catch. After they caught the kitten, they took it to a local Humane Society, where it was euthanized because of the bite. This ended up being an efficient approach, but more often there would be a 10 day observation period of an animal that had bitten someone, to see if it developed signs of rabies. If signs occurred the animal would be euthanized and tested for rabies, but if not then (theoretically) the animal would not have been shedding rabies virus at the time the bite occurred. Immediate euthanasia after a bite is not the typical recommendation, so I wonder whether the kitten was already showing some signs of disease. Otherwise, it wasn't a textbook approach to bite management but it ultimately resulted in the right outcome.
These cases have a few recurring themes:
- Changes in animal behaviour should lead to consideration of rabies.
- Be wary of stray animals. It's best to stay away from them. If you end up taking in a stray, if it gets sick and dies, ensure that it is tested for rabies.
- Vaccinate your pets because you never know when you'll encounter rabies.
When I was in general practice, I remember going into an appointment and being introduced by an owner to his cat named "Big Screen TV." Upon seeing my surprise at the name, the owner explained that the medical emergency the cat had the year before cost as much as the big screen TV he wanted, so he renamed the cat.
If that's the case, then L.A. Times columnist David Lazarus might want to call his cat "SUV." Lararus developed an infection after a cat bite that required surgery and extensive medical care. His hand was saved, at a cost of about $55 000. The article describing the ordeal it is focused on the financial aspect and the bizarre approach to hospital billing in the US, so there's not much information on the bite or the infection itself, but it's yet another example of why preventing bites and good bite care is important, regardless of how serious the bite may appear at first.
I seem to write about this bug a lot - disproportionately for a rare cause of infection - but it just keeps getting attention. Reading the title of a recent article "Woman loses legs, fingers to rare infection from dog bite," it was an easy guess that the infection was caused by Capnocytophaga canimorsus. That's the type of dramatic disease this bug can cause, and as hard as it is to say "lucky" about someone that loses digits or limbs, they are lucky since death rates are very high with this infection.
Capnocytophaga canimorsus is a strange little bacterium. It's found in the mouth of pretty much every dog, so people get exposed to it quite commonly, yet it rarely causes disease. However, when it does cause disease (often after an otherwise inconsequential bite), it's bad.
In the most recent report, a 48 year old woman received some minor bites breaking up a fight between two family dogs. The next night, she had a fever and was vomiting, and things went downhill from there (click here to read the full story). An unusual aspect of this case was that the woman didn't have any of the risk factors that are typically present in a person who gets a Capno infection, such as not having a spleen, being an alcoholic or having an immunosuppressive disease. It is unclear why this bug, which is normally quite innocuous to an otherwise healthy person, almost killed her.
An infectious disease physician at the hospital made a few recommendations:
"If a person experiences a dog or cat bite it’s reasonable to have it examined, especially if it’s swollen, painful or red."
- Pretty good advice. It's never a bad idea to get a bite examined, and in some situations, it should be mandatory (e.g. bites over the hands or face, bites to immunocompromised individuals).
"It’s important for the public to not only closely watch animal bites but also to make sure pets are current on their shots and that the owners are up-to-date on tetanus shots."
- Good general advice, but not really related to Capno.
"Dog owners should use caution when trying to break up a fight between animals, she said. Instead of reaching near a dog’s mouth, pull the tail, she advised."
- I'm not so sure about this one. Grabbing a tail of a fighting dog sounds like a good way to get bitten, although reaching near the mouth of a fighting dog would be just as bad or worse.
"Animals that are the source of such infections don’t need to be euthanized, Mondy said, but the dog that bit Sullins was put down for various reasons, including increasing aggressiveness and concerns about exposing babies in the family to the animal."
- Capnocytophaga should never be a reason to euthanize a dog since basically every dog is a carrier. It doesn't matter if there's a baby in the house or not. If the dog's dangerous because of its biting, that's a different story.
This article, along with various other recent reports, makes me ask a couple of questions:
Are Capnocytophaga canimorsus infections getting more common?
- I don't know. It's possible, as disease trends can change. It could also be that reporters are picking up these cases more often since they tend to be dramatic.
Are more low-risk people becoming infected?
- This one concerns me a bit. Traditionally, when I saw a report of Capnocytophaga in the literature or lay press, I could guarantee I'd eventually come across a statement about the person not having a spleen, or less commonly being an alcoholic or having some other immunocompromising problem. Again, it may just be my impression but I'm seeing more reports where a risk factor isn't apparent. It could be that an immunocompromising problem is there but is not known, but this report, along with some other recent news articles and a published case report, raise concern about the potential for this bug to cause disease in the absence of traditional risk factors.
This doesn't mean owners should fear their dogs, since it's still a very rare problem. However, it re-inforces the need to:
- Reduce the risk of bites through proper training (of both the dog and people who interact with it).
- Use prompt and proper first aid measures after any bite.
- Ensure that people who are at high risk for infection, particularly people without a spleen and those with compromised immune systems, always seek medical attention promptly after a bite.
I write a lot about animal bites, and for good reason since they are common and can be very severe. Usually, it’s dog bites. Sometimes it’s cat bites, or more rarely injuries from birds or other critters. Monkey bites not so much, but they happen. I had an email question about rabies exposure from a monkey bite the other day, and there was a paper in the October edition of Emerging Infectious Diseases about monkey bites amongst US military personnel in Afghanistan.
Some highlights of that paper:
From 2001-2010, 643 animal bites were reported by US military personnel.
- More probably occurred since bites are often underreported.
Dogs accounted for 50% of bites, but many other animals were also involved, including rhesus macaques, a type of primate that is present in the wild and also kept as pets in Afghanistan.
- Macaque bites are even more of a concern than dog bites. In addition to the ever-present risk of rabies exposure, these animals can also transmit Macacine herpesvirus B, which is a very serious pathogen that can kill people. Like any animal, macaques also have a wide array of bacteria in their mouths that can cause infections after a bite.
10 monkey bites were reported in this series.
- Most people who were bitten were young (less than 30 years of age) and male. All were junior enlisted personnel or non-commissioned officers.
- Eight of the monkeys that bit were pets, including one that somehow belonged to US military members (despite orders that US military personnel not adopt or interact with local animals or pets).
- Appropriate wound care was provided following only six of the bites. So, there are deficiencies in understanding basic first aid following bites.
- Only five people received appropriate treatment for herpes B exposure. That’s a concern because of how serious this infection can be.
- Eight received antibiotics. Antibiotics are only indicated in a subset of bites, mainly based on what part of the body is bitten, so it's not clear whether this was really needed (while more concerning issues went unchecked).
- Eight received treatment for rabies exposure.
- No one got sick, fortunately.
Monkey bites aren’t something that most people need to be concerned about in their daily lives, but they are a concern for people living in areas where there are monkeys, as well as those who visit such areas. (I have a vivid memory of swinging a camera case at a monkey in Barbados that for some reason seemed to be less than impressed with my existence).
Bites happen, but some are avoidable. Common sense can reduce the risk. If common sense isn’t enough and you’re bitten, don't panic, but you also can't ignore it. After thoroughly cleaning the wound, it's important to get medical advice about what diseases are of concern and whether anything else can or needs to be done. Physicians working in foreign countries also need to be trained on geographically-relevant risks. Monkey-associated infections are not high on the curriculum of US medical schools, so geographically-relevant training is required for people heading elsewhere to work.
Public health personnel in Chapin, Connecticut (USA) are trying to find a woman bitten by a rabid cat. The woman was driving down South Brear Hill Road when she came across a cat. She picked the cat up from the road and told someone else who was there that the cat bit her. She then drove away, and the cat was subsequently identified as being rabid. Now a search is underway to find the woman so she can be given post-exposure treatment.
This is clearly a high risk situation. As opposed to other public health alerts that try to find people who were in contact with a rabid animal on the off chance that they were bitten or otherwise exposed to the virus, this person was bitten and that creates a very high risk of rabies transmission.
The outcome is simple.
- If she gets rabies, she will almost certainly die.
- If she was exposed but gets post-exposure treatment soon (and completes the recommended course), she will almost certainly live.
It's easy to see how this could happen. The woman probably found the cat looking injured or lost on the road, and wanted to help. However, that action, and failure to recognize the risk associated with the bite, have put her life at risk.
A few general rabies reminders:
- Avoid contact with wildlife or any animals you don't know, especially if they seem sick or otherwise abnormal.
- If you are bitten, make sure the potential for rabies exposure is considered. The animal needs to be observed to see if it is rabid, or it needs to be tested. If the animal can't be monitored or tested, you can't rule out rabies and getting post-exposure treatment is the safest course of action.
More information about rabies can be found on the Worms & Germs Resources - Pets page.
a) there are more rabid beavers these days,
b) rabid beavers have always been around in these numbers but they have recently acquired a taste for human flesh, or
c) it's just a fluke,
The latest incident involved a beaver in West Springfield, Virginia that chased after some kids at a nature centre. The kids had been swimming and saw a beaver swimming towards the dock. It's not that unusual to see beaver's swimming around in some areas, but like most wildlife, they typically stay away from people. Not this one though. It "leaped out of the water onto the dock, acting aggressively and chasing the children." Police shot the animal and testing confirmed it was rabid. Presumably, no one required post-exposure treatment since there were no bites.
While rabid beavers are rare, this and earlier incidents involving attacks by rabid beavers, otters and other critters highlight some basic principles regarding rabies safety:
- Stay away from wildlife.
- Mammalian wildlife that are acting abnormally, including displaying no fear of humans, should be considered rabid until proven otherwise.
- Any bite by a wild mammal should be considered a potential rabies exposure. The animal should be tested whenever possible and if it can't be shown that the animal wasn't rabid, it must be assumed that there was rabies exposure.
Common sense goes a long way toward avoiding rabies exposure, but sometimes it's not avoidable. Knowing what to do in the event of a bite from a wild and potentially rabid animal is important. The key is involving physicians and public health personnel who understand rabies exposure risks, so that a proper risk assessment can be done and treatment can be started promptly if it's indicated.
Image: A North American Beaver (Castor canadensis), by Laszlo Ilyes (click image for source)
- The Indian River Reptile Zoo near Peterborough, Ontario, rushed some of their stock of snake anti-venom to Brantford General Hospital (about three hours away) to aid in the treatment of a woman who had been bitten by a Copperhead snake. Hospitals in Ontario don't tend to stock anti-venom for snakes that don't live anywhere near here, and it's fortunate for the woman that a couple of zoos in Canada stock anti-venom and are willing to share it (and that those zoos happen to be in Ontario and not the other side of the country). Circumstances of the bite aren't clear but the woman or someone she visited a) is obviously keeping a dangerous snake and b) obviously isn't handling it properly. Indian River Reptile Zoo president Bry Loyst sums up some of the problems with snake bites, saying "Hospitals are amazing but they don't have the expertise right there,” and “You'd be surprised at how many venomous snakes there are out there [in Ontario homes].”
- JayJay, a pet macaque (a kind of monkey) from Okeechobee, FL, was shot after "flipping out" and attacking its owner, "ripping apart his hand." The primate, who wore diapers and played with kids, had lived with the family for nine years, having been acquired at three weeks of age. He got out of the house and his owner was trying to catch him with a net. Whether it was the net, the joy of freedom or some other reason, JayJay lost it and clamped down on his owner's buttocks, thigh and hand, respectively, refusing to let go. A friend had a gun handy (no comment) and shot the monkey at the owner’s behest. The bite on the hand (in particular) was severe and deep, damaging tendons and a nerve, requiring surgical repair. This is another example of the "loving" exotic family pet going berserk for some unknown reason. The macaque often played with kids and the owners took him out in public (e.g. dressing him up and taking him trick-or-treating at Halloween). If we can say anything good about this, it’s good that it was the adult owner who was attacked and not a child. Fortunately, unlike a large percentage of captive macaques, JayJay wasn’t a carrier of herpes B virus, a virus that can rarely cause fatal infections in people. A good closing statement was made by Lion Country Safari wildlife director "Anybody that keeps a monkey is going to get bit... I haven't heard of a monkey that wouldn't bite someone."
- A zookeeper in Berlin, Germany, was killed by a Siberian tiger that had escaped its enclosure. While not a pet, it’s another example of a fatal attack by a captive large cat. As with venomous snakes, there is a remarkably large number of these animals that are privately owned, and attacks certainly happen. Usually, the lucky survivors say it was a "freak incident" and totally unexpected because the animal was like a pet cat. The unlucky ones can’t talk, but often the same story comes from friends and family… the animal was this apparently loving, docile large cat that for some reason attacked. You can never be confident that these animals are safe, because fatal injuries can occur not just with attacks, but with playful behaviour given their size and strength.
- In a related theme, a cougar was shot and killed in Muskoka Lakes, Ontario, after attacking a pet dog. The fact that the cougar had been declawed was a pretty good indication that it was an escaped pet. The owner of Guha's Tiger and Lion Farm, an "exotic animal menagerie" located down the road from where the cougar was shot, says he is not missing any of his cougars, which would "never want to escape" (except, I guess, for the jaguar that was shot by police after escaping in 2008). Since there's no regulation of exotic animals in the province, no one will know for sure from where the cougar came, how many cougars are present in Ontario and how they are being managed. Hopefully Mr. Guha has a containment plan for his other cougars, lions and jaguar that goes beyond assuming they'd never want to leave. If I was a neighbour, I wouldn't be too confident, however, when he says things like "If I leave the gate open for some reason — like I unlock it, then the phone rings so I pick up the phone — if they do get out they’ll go sit by (my front door) and wait for me."
It might just be my perception, but it seems like there are a lot more reports of nasty dog bite infections in the news lately, particularly infections caused by the bacterium Capnocytophaga canimorsus. I don't know whether that's because they are becoming more common, more commonly diagnosed (since the bug is hard to identify), more commonly reported in the press or a combination of all three (or whether my perception is simply incorrect).
The latest report is from Omaha, Nebraska, where a 50-year-old man died four days after suffering a minor dog bite on the cheek. The cause of infection wasn't reported, but the article says that he was unable to fight the infection because he didn't have a spleen. For me, minor bite + fatal infection + no spleen = Capnocytophaga infection until proven otherwise, since this is a textbook description of such an infection, and Capnocytophaga can be found in the mouth of virtually every dog.
This follows the high-profile case of a cancer survivor who lost her hands and feet from Capnocytophaga infection complications and a UK inquest into the death of a man caused by infection with this bacterium, among other cases.
Here are the simple take home messages:
- Avoid bites and any interactions whereby dog saliva may come in contact with non-intact skin.
- Know if you are at high-risk for an infection caused by a bug like Capnocytophaga. This bacterium typically doesn't cause disease in healthy individuals but can produce rapidly fatal disease in certain people.
- Realize that minor bites can cause major problems (even if you are otherwise healthy).
- Use good first aid practices if you or someone you're with is bitten, including careful washing of the wound and seeking medical care if you are at increased risk of infection, or if the bite is over the hands, feet, face, joints or other sensitive areas.
I've had a run on questions about survival of rabies virus outside the body. The topic comes up periodically with respect to touching roadkill or veterinary clinic personnel working with animals that have been attacked by an unknown animal. The case of three people who developed rabies after taking care of a sheep that had been attacked by a rabid animal, probably through contact with saliva from the rabid animal on the sheep's coat coming into contact with broken skin on their hands, shows the potential risk. An important part of assessing the risk is understanding how long the virus lives outside the body.
Some viruses are very hardy and can live for weeks or even years outside the body. Parvovirus and norovirus are classic examples of this type. Some viruses, like HIV, die very quickly in the environment. Part of this relates to whether they are "enveloped" or "non-enveloped" viruses. Enveloped viruses have a coating that is susceptible to damage from environmental effects, disinfectants and other challenges. Damaging this coating kills the virus. Non-enveloped viruses don't have that susceptible coating and that is in part why they are so much hardier.
Fortunately, rabies is an enveloped virus, and it doesn't like being outside of a mammal's body. Data on rabies virus survival are pretty limited, since it's not an easy thing to assess. To look at rabies virus survival, you have to grow the virus, expose it to different environmental conditions, then see if it's still able to infect a mammal or a tissue culture. We can do this easily with bacteria, but growing viruses is more work, especially a dangerous virus such as rabies virus.
I can only find one study that has looked at rabies virus survival (and I can only read the abstract since the rest of the paper is in Czech). The study (Matouch et al, Vet Med (Praha) 1987) involved testing of rabies virus from the salivary gland of a naturally infected fox. They exposed the virus to different conditions and used two methods to look at the infectivity of the virus.
- When the virus was spread in a thin layer onto surfaces like glass, metal or leaves, the longest survival was 144 hours at 5 degrees C (that's ~ 41F).
- At 20C (68F), the virus was infective for 24h on glass and leaves and 48h on metal.
- At 30C (86F), the virus didn't last long, being inactivated within 1.5h with exposure to sunlight and 20h without sunlight.
So, rabies virus can survive for a while outside the body. Temperature, humidity, sunlight exposure and surface type all probably play important roles, but in any particular situation you can never make a very accurate prediction of the virus's survival beyond "it will survive for a while, but not very long."
From a practical standpoint, it just reinforces some common themes:
- People should avoid contact with dead or injured animals.
- Veterinary personnel or pet owners dealing with a pet that has been attacked by another animal should wear gloves, wash their hands and take particular care if they have damaged skin.
- People who are at higher than normal risk of being exposed to potentially rabies-contaminated surfaces should be vaccinated against rabies.
Image: Schematic diagram of a rabies virus showing the outer viral envelope (source: CDC Public Health Image Library)
Israel's Health Ministry is recommending rabies vaccination for people traveling to India.This seems to be mainly in response to the recent high-profile case of an English woman who died of rabies acquired from a dog in India. While it was high-profile, that certainly wasn't the only travel-associated rabies infection in the past year. Rabies exposure is a serious concern for people who might encounter dogs (intentionally or accidentally) while traveling in countries with endemic canine rabies. The news report states that rabies vaccine is available at clinics in Israel for would-be travelers, however it doesn't say whether the cost of vaccination is covered by the government. Human rabies vaccination is quite expensive, which may be a limiting factor when it comes to convincing travelers to get vaccinated, unless the government foots some or all of the cost.
Raising awareness of the problem with rabies in some developing countries is good. Most people don't really think about travel-associated disease (beyond the ubiquitous diarrhea that comes with travel to some areas), particularly something like rabies. In addition to focusing on vaccination, however, it would be even better to see a broader initiative to remind people to avoid contact with stray dogs (and other animals) and to make sure they get proper medical care after potential rabies exposure. Also, while India is certainly a hotbed of canine rabies, it's important to remember that there are many other countries where dog rabies is a major problem, and similar measures need to be taken for travel to these places too.
A surprisingly large number of people get sick and die every year from diseases acquired during travel. Travelers need to be aware of disease risks in areas they visit, know what preventive measures they should take and how to get proper medical care in any region they visit. While thinking about this might put a damper on vacation planning, it's worth the effort. When it comes to rabies, unless you know that a region is officially (and truly) rabies-free, assume that any encounter with a wild mammal, especially a stray dog, could be a source of rabies exposure. You don't want to travel in a bubble and stick to sterile locales, but you also don't want to come down with a fatal disease when some basic precautions could have prevented it.
An inquest into the dog-bite-associated death of Gary Dickinson, age 57, is underway in the UK. When people think about deaths from dog bites, they usually think about death from severe trauma, especially in kids. However, as I've mentioned repeatedly, minor bites can also pose major risks.
Mr. Dickinson died in February, only three days after being nipped in the finger while breaking up a fight between his dogs. It was a minor bite that many people would quickly dismiss. However, trauma isn't the only possible problem with bites. Infections from bites can be very serious, and in some situations all it takes is a very small break in the skin to allow bacteria to move into the tissues.
Despite suffering no consequences from the initial trauma of the bite, Mr. Dickinson was feeling sick by the next day. He went to the hospital and was sent home with a diagnosis of food poisoning (probably based on vague signs and lack of any other obvious diagnosis, rather than any true evidence of food poisoning. A key question here is whether the dog bite was mentioned at the hospital, which is unclear to me).
Mr. Dickinson deteriorated rapidly after returning home and was rushed back to hospital. Despite aggressive treatment, he died just six hours after admission. The diagnosis was Capnocytophaga infection, and this is a pretty classic picture of this rare but devastating infection.
Capnocytophaga is a type of bacterium that is found in the mouths of dogs. Pretty much every dog has loads of it in the mouth, and people are very commonly exposed through contact with saliva. Fortunately, it rarely causes infections and usually is only a problem in people with compromised immune systems. People who do not have a functional spleen (typically because it has been removed for one reason or another) are the classical high risk group for Capnocytophaga infection. Alcoholics are another high risk group, and that appears to have been the issue in this case.
Minor bites are usually just that - minor. However, sometimes very bad things can happen following very minor bites. Serious consequences are most common in young kids, the elderly and people with compromised immune systems (especially people who have had their spleen removed). While no one should panic after a mild bite, everyone should take any bite seriously. In most situations, thorough cleaning of the wound is adequate, but bites over critical areas (e.g. face, joints, hands) or in high risk people need to be assessed promptly by a physician.
More information about bites can be found on the Worms & Germs Resources - Pets page.
A 50-year-old UK woman, the first of two recent travel-associated rabies cases in the UK, has unfortunately but not surprisingly succumbed to the infection.
The woman was bitten by a puppy while traveling in India. Given the widespread nature of rabies in dogs in India and the large number of human rabies deaths associated with canine rabies there, this was a high-risk exposure. I still haven't seen any information about whether she sought medical care in India or not. Too often, people don't bother to go to a doctor after being bitten, especially if the bite appears minor - but even a minor bite can transmit rabies. Furthermore, people don't always get the care they need, since rabies treatment is astoundingly not always offered after dog bites in India, and rabies vaccine and antibody may sometimes be in short supply.
Whatever happened in India, the woman was reportedly turned away twice by doctors back home at Darent Valley Hospital in Dartford, Kent. It's not clear why, and an investigation is underway, but it's not necessarily surprising since signs of rabies can be very vague at first. Initial signs could mimic a range of minor illnesses, and if the doctors didn't know that the woman was bitten by a dog in India, rabies presumably (and reasonably) wouldn't be considered, especially since it's not present in the UK.
In what is hopefully a case of misquoting or misinterpretation, Dr. Ron Behrens of the London School of Hygiene and Tropical Medicine is quoted as saying that there is a 24 hour window after a bite when antibody treatment can prevent the virus from entering the nervous system. In reality, it's not that quick and the incubation period can be very long in some cases. Post-exposure treatment can be highly effective even if it's given well after exposure, as long as it's before signs of rabies occur. Prompt treatment is always best.
An Albany, Georgia woman is fortunately recovering from necrotizing fasciitis (flesh eating disease) that developed after a cat bite. The cat presumably wasn't the source of the bacterium that caused the disease, but it was the source of the wound that let the bacterium (usually Group A Streptococcus sp) get into her body in the first place, and from there the infection spread rapidly.
In this case, the woman was bitten on the hand by her cat. There's no mention of what she did after the bite, but often people don't take adequate precautions after cat bites because they can appear minor. While the trauma can be minor, cat bites are notorious for causing infections because they can drive bacteria deep into tissues, making it easy for infections to develop.
Four days after the cat bite, the woman's hand "blew up" and she was rushed into surgery. It's an emergency situation because death rates can be high, and those people lucky enough to survive can still have serious complications sometimes requiring measures as drastic as limb amputation, and the extensive tissue damage can lead to chronic problems for the rest of their lives.
People shouldn't worry about getting flesh eating disease from their cat (in part because people don't actually get this kind of infection from cats, it's just that bites can predisposed them to this (and other) kind of infection). However, people should be aware of potential issues associated with bites (from cats in particular, but also from any kind of animal). This case is just one more warning about a range of potential problems that can develop following a cat bite. Any cat bite should be taken seriously and at a minimum promptly and thoroughly cleaned. Bites that occur over the hands, feet, face, joints and similar high risk sites or that occur in people with compromised immune systems should be evaluated by a physician - and sooner rather than later. It's much easier and better to prevent an infection from developing than to try to control an established infection, and while most cat bite infections are mild, serious problems are far from rare.
More information about cat bites can be found on the Worms & Germs Resources - Pets page.
Identification of the strain of rabies in the first person in Toronto to be diagnosed with rabies in the past 81 years has essentially confirmed that the infection was acquired abroad. Toronto Public Health has indicated that the strain obtained from the infected man is one known to circulate in dogs in the Dominican Republic, where the man had been working over the past few months.
Little additional information is being released, including whether the patient is alive (and if so, what his condition is). As part of the typical rabies investigation, 15 healthcare workers and an unknown number of family members and friends have been deemed to have been potentially exposed to rabies from the man and have been offered post-exposure treatment. The risk of human-human transmission is exceedingly low, but given the severity of disease, the logical approach is to err well on the side of caution when considering post-exposure treatment.
While rabies strain typing supports a dog bite as the source, that can't be confirmed at this time since the man was too ill to provide any information by the time rabies was being investigated. Sometimes, exposure is determined indirectly based on information from friends and family (e.g. the person mentioning that he was bitten by a dog) and presumably there is an effort to question people who had contact with the man in the Dominican Republic to try to piece this story together.
The unfortunate victim was a 73-year-old Haitian women. She initially went to an emergency room with a complaint of right shoulder pain, chest pain, headaches and high blood pressure. Difficulty swallowing was also noted when she was given pain medications, but she declined further testing and was discharged. It's not surprising that rabies wasn't considered at this point, although I doubt she was asked about animal contact or animal bites as a routine history question.
The next day, the woman went to two different emergency rooms, complaining of shortness of breath, spasms, hallucinations and balance problems. A cause was still not readily apparent, and over the next couple of days, her condition deteriorated, with development of more neurological abnormalities including tremors and mild seizures. Encephalitis (inflammation of the brain) was diagnosed, and a range of potential causes were ruled out. A nuchal skin biospy was collected for rabies testing but she was declared brain dead by the time results were obtained.
The strain of rabies that was identified most closely matched a canine rabies virus variant from a person in Florida who acquired rabies in 2004 while in Haiti. Upon further investigation, a cousin recalled that the person had been bitten by a dog in Haiti a few months earlier. The bite wasn't considered severe and medical attention wasn't sought.
As an almost invariably fatal infection but an almost completely preventable disease with proper medical care, education is a key aspect of rabies control, and that's where most of the breakdowns occur. This person didn't seek medical attention after the bite, because the bite wasn't too severe. Unfortunately, mild bites can transfer rabies just like severe bites, and any bite needs to be investigated as a potential source of rabies, particularly in highly endemic areas.
Canine rabies is a major problem internationally, accounting for tens of thousands of human deaths each year. Canine rabies has been eradicated in the US, meaning the canine rabies virus strain is no longer circulating. That doesn't mean dogs in the US can't get rabies, since they can be infected with various wildlife strains, but there is not a circulating pool of canine rabies virus like in some other regions. Canine rabies is still endemic in Haiti, although there have been efforts to control it through education and vaccination of dogs and cats in the country (where less than 50% of dogs and cats are vaccinated).
People living and traveling to rabies-endemic regions like Haiti need to be aware of the potential risk of rabies and consider any dog bite a possible rabies exposure. Similarly, healthcare workers need to query animal exposure and animal bites as a routine practice, since as with this case, rabies can be hard to diagnose initially.
It seems like pet bite articles come in waves, with a recent cluster showing the variable quality in advice that's available.
Often, they are holiday "filler" articles that provide some basic useful information but overall are of limited use or even harmful based on their very superficial approach. They often mention rabies, get a quick quote from a veterinarian or someone in public health, but don't emphasize the potential problems that can occur with even apparently minor bites. The thing that often raises my ire is the common statement about watching the bite and going to a doctor if your limb swells up or has pus oozing out, without talking about the need for proper post-bite care to actually prevent that from happening.
Anyway, I came across a couple of better articles recently, that get some good information across in a nice, readable manner. One, an article in "The Herald News" entitled "Cat bites always require check by doctor", gets a very important point across quickly.
The news story details the saga of the PJ, a 13-year-old cat, and his owner. PJ bit the woman on the arm causing a seemingly minor wound, but by the next day, her arm was red and swollen, necessitating a round of intravenous antibiotics and four days in hospital. In the article, Gail Steele, an infection prevention nurse, states "Cat bites.. must always be considered medical emergencies. This is especially true when they occur in the hand because that area has a richer blood supply...Their sharp little teeth are like little needles, and they inject bacteria right into soft tissue..."
This is a pretty extreme example of what can happen after a cat bite, but it's far from rare. It's not really clear whether this person's infection would have been prevented with normal practices. Bites over certain sites, like the hand, foot, joints, tendon sheaths and prosthetic devices, and bites to young kids, elderly individuals and people with compromised immune systems typically require prophylactic antibiotics.
If this was actually a bite over the arm, as reported, antibiotics might not have been given, even though cat bites are much higher risk for infection than dog bites. However, the key is that bites should be assessed so proper determination can be made about the need for antibiotics. All infections won't be prevented but appropriate medical care should reduce the risk and also allow for adequate consideration of whether rabies exposure might be a concern.
There's a sad end to this article, as PJ bit his owner again a few months later. The bite was over the shin and, given her previous problems, antibiotics were provided. However, the owner still ended up with an abscess that required surgical intervention and took months to heal. (Whether this person has really bad luck, whether PJ has a particularly bad mix of bugs in his mouth or whether the owner has an unidentified problem with her immune system is unclear, but back-to-back severe infections is a major issue, especially with a cat that is prone to biting.) The woman's daughter ended up taking PJ home with her, but after another unprovoked bite, he was euthanized.
Cat bites aren't always this bad, and in fact, most don't result in complications. However, that's not to downplay the potential problems. When you consider how often cats bite, how often cat bites are not properly cared for because they appear to be minor, and the ability of a cat bite to inoculate bacteria deep into the tissues, it's easy to see how bad things can happen. Reducing the risk of cat bite infections involves a few basic steps:
- Reducing bites. Good handling and training (of both cats and people) can reduce the likelihood of bites. This is particularly important with kids, who may be bitten through rough or excessive handling of a cat.
- Bite first aid. Prompt cleaning of the wound can reduce bacterial contamination. Thorough cleaning with soap and water can have a big impact on the likelihood of infection.
- Medical care. Bites over certain sites or to certain individuals (see above) almost always require antibiotics. There's less consensus over other types of bites, but getting medical care is a good idea in any case to determine if there are any factors that indicate a need for antibiotics.
- Rabies avoidance. Every bite should be reported to public health so the rabies aspect can be covered. The biting animal needs to be identified and observed for 10 days. If it's healthy after 10 days, it couldn't have been shedding rabies virus. If the biting animal cannot be identified, it's likely that post-exposure treatment for rabies will be required.
One problem with keeping uncommon animal species as pets is that we don't know much about them from an infectious disease standpoint. Some species end up being pretty low risk while others end up causing unexpected infectious disease challenges.
A Texas family found this out the hard way, after their 16-year-old daughter got sick after being bitten by a kinkajou. Kinkajous are strange little critters that are somewhat related to raccoons. Paris Hilton helped fuel the kinkajou fad a few years about after she adopted one (and was bitten by it shortly thereafter). They tend not be be good pets because they are nocturnal and can be antisocial or aggressive during the day (like a lot of people that are kept awake when they want to be asleep).
I wrote earlier this year about concerns regarding the raccoon roundworm, Baylisascaris procyonis, in kinkajous. This more recent report involves an infection that set in after the Texas girl was bitten by her aunt's six-week-old kinkajou. Within 24 hours of being bitten, the girl was severely ill and ended up in hospital for six days. She was treated with antibiotics and responded to treatment.
Because "kinka-what?" was the response to being told that the girl had been bitten, the family and their doctors researched diseases that might be associate with kinkajou exposure. One thing they found was a bacterium called Kingella potus, which was recently found in kinkajous (and subsequently in people with kinkajou bites). Nowhere in the news report does it actually say that this bacterium was identified in the girl, so it's unclear what really happened.
This is yet another example of what can happen when people buy pets that neither they nor the veterinary and medical communities know much about. The recent debacle in Ohio that culminated in the deaths of a large number of exotic animals was a high profile example of the weak to non-existent laws (or enforcement) pertaining to exotic animals in many areas, something that continues to put both animals and people at risk.
A recent article in the Toronto Sun described one physician's approach to dealing with dig bites in kids. It contains some useful information, but also a couple of areas that probably require some clarification.
In the article, the physician lays out a few points regarding management of dog bites in kids:
The first thing a parent should do after such a bite is to stop the bleeding by applying pressure. Then, clean the area with warm water and soap. Dogs, like humans, have dirty mouths, so you want to wash and rinse well and even flush out the wound if it's deep.
- "The solution to pollution is dilution" is a old adage. Thorough cleaning is a critical step.
If the bite wound is small, it's usually not sutured, as this might increase the risk of infection. On the other hand, facial wounds and larger bites have to be well cleansed and irrigated, and may require stitches. The sooner this can be done the better.
For a child with a dog bite that has broken the skin, most pediatricians would recommend a seven-day course of an antibiotic, typically Augmentin (unless the child is allergic to penicillin).
- I'm not sure "most" doctors would start a child on antibiotics after any bite that has broken the skin - at least I hope not. Typical recommendations for bites include that antibiotics should be considered with moderate to severe injuries, puncture wounds, people with compromised immune systems and bites over specific areas like joints or the face. Antibiotics for minor soft tissue injuries in otherwise healthy individuals are not typically recommended, although there is some controversy.
Rabies is usually not a risk in dogs that are family pets and live in homes. If the dog is not known or their rabies status is unclear and you can't locate the pet, check with your pediatrician about rabies prophylaxis.
- True. Rabies from pet dogs is very rare in North America. However, if you get it, you almost certainly die, so we take precautions even in low risk situations. So, a little more discussion of this point is important.
- Every dog bite must be approached as a potential rabies exposure. Key points for this are identifying the dog and ensuring it's quarantined for 10 days. After 10 days, if it's healthy, it couldn't have transmitted rabies with the bite. Related to this, any dog bite should be reported to local Public Health personnel. They will ensure that quarantine is imposed if the dog is known, and facilitate rabies post-exposure prophylaxis in the rare situations that it is needed. In Ontario, physicians are bound by law to report bites to Public Health.
Dog bites are unfortunately very common. Usually they are minor and heal without much trouble, but serious or fatal injuries can occur and infections are a potential problem. Knowing what to do in response to a dog bite is important to reduce the risk of a range of complications.
Sunday's Toronto Sun contained an article entitled "Woman's hand disfigured by cat attack" with the compulsory gross picture. The story is about Brenda Sims, who took in a feral cat, was then bitten by the cat, and then developed severe complications from the bite. The situation is a reminder of the potential problems encountered when dealing with feral animals (cats included) and complications that can occur from any cat bite.
Back in April, Ms. Sims took in a young male cat that she described as "five pounds of pure disease." The cat, named Cheech, had been taken off the streets and was clearly not someone's lost pet. Cheech began following her around the house, growling and hissing. Not surprisingly, the well-meaning woman was eventually bitten.
Ms. Sims has had multiple surgeries since then, including one that removed a large section of tissue from her hand and replaced it with some taken from her thigh. She's been largely unable to work since the injury and faces long term problems with function and appearance of her hand.
Ms. Sims is warning people about the dangers of feral cats. "It's like taking a tiger out of the jungle and into your home, and expecting it to be all good, and be a house cat..."
Dr. John Embil, Director of Infection Prevention and Control for the Winnipeg Regional Health Authority echoes her warning about feral cats, adding that feral cats can transmit rabies or severe bacterial infections such as Pasteurella multocida through bites. That's very true and a good reminder, but it perhaps overstates the importance of "feral." Any cat can carry Pasteurella multocida, along with many other problematic bacteria, in its mouth. A bite from any cat - domestic or feral - can cause serious infections. While an individual feral cat may be more likely to bite than am individual pet cat, most cat bites and cat bite infections are presumably from pet cats because people have more contact with them.
Dr. Embil highlights the problem with cat bites: "The concern we have with cat bites is that the teeth are very long, sharp and pointy. And those teeth can puncture deeply. You can get serious infections." Cat bites can be similar to injecting a bacterial cocktail deep into the tissues, not surprisingly resulting in infection in many cases.
Some take home messages:
- Leave rescuing feral cats to people with experience.
- If you want to rescue a cat, get it from a shelter, humane society or other reputable and experienced organization. They will have assessed the cat's behaviour and health status, which will decrease the chance that you'll get an aggressive and/or sick cat.
- If a cat constantly stalks you around the house looking like it's going to attack (and not like it wants to play), it probably will attack and it shouldn't be in your house.
- Any cat bite can cause severe complications. Every cat bite should be taken seriously and medical advice should be sought. Bites over the hands, feet, joints, tendons, genitals or in people with compromised immune systems typically require antibiotics to help prevent infection.
More information about cat bites can be found on the Worms & Germs Resources page.
A 35-year-old UK man has died following a seemingly innocuous dog bite. He was nipped by the family's pet dog, not during an aggressive incident but just a playful, boisterous dog. Later, he developed a fever. He saw a doctor the next day and was told that he had influenza based on his clinical signs, but no testing was done. There's no mention about whether the doctor was notified about the dog bite or asked about animal bites or contact. (I wouldn't be surprised if that didn't happen.)
Unfortunately, the man's condition deteriorated and he was diagnosed with sepsis, which is an overwhelming infection of the bloodstream. A dog-associated bacterium, Capnocytophaga canimorsus, was identified as the cause. Both of the man's leg's were amputated because of the effects of the infection, after which he started to improve, but he later developed more complications and ultimately died.
A doctor explained, "These things are so unusual. It would have been like an unstoppable train – it just depends on how the body reacts." Infection with C. canimorsus is rare, and once it's underway, it can be difficult to control. However, this quote neglects the potential treatable aspect of the infection. For an aggressive infection like this, diagnosing it early is critical. If the doctor had asked about pet contact, asked about bites, noticed the bite, or if the person had mentioned the dog bite at the first visit, an astute physician may have thought about bite-associated infection and hopefully started proper treatment, before fulminant sepsis developed. This would be particularly true for certain high-risk individuals.
Capnocytophaga infections occur almost exclusively in high-risk people, particularly people without a spleen, but also in immunocompromised individuals or alcoholics. There's no mention of whether this person had any of these risk factors, but people who do should know that they are at high risk, see a physician if they are ever bitten by an animal (even if it seems like a very minor bite), and make sure their physician knows about pet contact.
Avoiding Capnocytophaga is essentially impossible if you have a dog. It's carried in the mouths of most (if not all) dogs, but it's typically not an issue. Human infections are rare but they are important because, like in this case, they tend to be very severe when they do occur. High-risk individuals need to know about this bug, make sure their physician knows about any animal contact they have, be proactive to avoid bites and other exposure to dog saliva, thoroughly wash any bites or wounds contaminated with dog saliva, and consult a physician after any bite, regardless of how mild it may seem. Pet owners shouldn't be afraid of Capnocytophaga, but they should be aware of it and various other bite-associated pathogens, do their best to reduce the risk of bites occurring (e.g. proper training of dogs (and kids)), and know how to take care of bites.
Another recent incident highlights yet again problems with untrained or inadequately trained service dogs.
The incident in question occurred in March, when Ava, a 14-month-old German Shepherd "service animal," lunged at a six-year-old child who lived next door. It sounds like the dog was roaming free and attacked the girl on her property. There's some debate about whether or not the girl was playing with the dog (which doesn't really matter because a service dog shouldn't attack under circumstances like that, nor should it be roaming at large). Anyway, the girl suffered a serious bite to her face that required more than 100 stitches to close.
Ava was owned by a family whose nine-year-old daughter has cancer. The dog was "trained" to steady the girl when she's dizzy. That may certainly be a good role for a service dog, as there is a wide range of beneficial activities that proper service dogs can perform. However, real service dogs are highly trained and closely evaluated, with a significant effort dedicated to making sure the dog is properly behaved and does not pose a risk to others. That's the problem here. While Ava might have been good for this one particular child, it doesn't sound like there was any training to protect the public (and if there was, it was woefully inadequate).
Ava apparently also bit another child in the fall, compounding the concerns. A settlement between the neighbours has resulted in the dog being removed from the township, with no declaration that she's dangerous, but also nothing preventing the likely lawsuit to recover medical costs, if not more.
There's nothing good that comes from a situation like this. A young girl has lost her dog, another young girl has suffered a serious bite, and true service dogs - that play a critical role in the lives of many people - get lumped in with these untrained animals.
If someone wants and needs a service dog, it's important to facilitate that. At the same time, if someone is going to take advantage of the benefits of having a service dog (e.g. broader access) they need to have an adequately trained, true service animal. Too many "service animals" are just pets with basically no additional training, but serious training is required for the animal to both do a real job as well as to ensure that there is minimal risk to the public.
A Montreal pediatrics resident has expressed concern about rat bite fever in kids. Dr. Karine Khatchadourian described three cases of this bacterial infection in a paper called "The rise of the rats: a growing paediatric issue," published last year in the journal Paediatrics and Child Health. The article didn't really present any evidence that this is a "growing" issue, but it is a disease of concern.
Rat bite fever is a bacterial infection most commonly (but not exclusively) associated with bites from rats. Healthy rats often carry the bacterium that causes the disease (Streptobacillis moniliformis in North America), and infection can occur when the bacterium is inoculated into the body by a bite, or when it's spread to mucous membranes like the mouth through direct mouth-mouth contact with pet rats (yes, some people kiss their rats).
The disease can be serious, and even fatal, if not properly diagnosed and treated. It's also a classic example of why physicians need to ask their patients about pet contact and why people need to take bites from pets seriously. Knowing that a rat is in the house, and particularly if a bite has occurred, is a key factor in helping make the diagnosis. If the physician doesn't ask the question, this critical piece of information may be missed, along with the diagnosis.
Being concerned about rat bite fever (and other zoonoses) is good, and ways to educate pet owners and physicians about such diseases are needed. However, extrapolating "rat bite fever is bad" to "rats are bad" is a stretch. The statement in the paper "Should we, as health care professionals, advocate to have rats banned from being sold in pets stores?" is over the top.
Every animal carries many microorganisms that can cause disease in people, given the right circumstances. Similarly, every person you meet is carrying something infectious. The key things to consider are:
- What is the likelihood of infection?
- How severe is the disease that may occur?
- What can be done to reduce the risk of infection?
- What is the cost-benefit, i.e. how do the potential risks compare to the potential benefits?
How can the risks be reduced?
- Rat owners need to be aware of the disease.
- Good handling practices are needed to reduce the risk of bites.
- Any bites that occur should be promptly cleaned and a physician contacted if there are concerns.
- Contact of rat saliva with broken skin or mucous membranes (e.g. kissing the rat) should be avoided.
- Physicians need to know whether their patients own pets, including rats, and know what diseases may be associated with those types of animals.
With this type of approach, the risk of infection can be reduced and the ability to properly and promptly diagnose the disease, in the odd case that it occurs, can be maximized.
I don't want to downplay rat bite fever. It certainly can cause illness, particularly in children under the age of 12. A recent paper reported a fatal case in a 14-month-old boy, however in that case the infection was associated with ferrets, not a rat.
Parents of small children need to think about the risks of zoonotic diseases, as well as injuries (e.g. bites) when deciding whether to get a pet, and what type of pet to get. If people like rats, take care of them properly and communicate well with their physician (and if their physician is aware of the issues), then the risks of serious disease are quite low.
Dr. Khatchadourian suggests that parents "should stick to cats and dogs, and steer clear of rats." However, that's no assurance that a zoonotic infection will not occur. There's no evidence indicating the risk of disease is less with those species. It doesn't even eliminate the risk of rat bite fever, since Streptobacillus moniliformis can be found in the mouths of dogs too.
Rather than banning rats from pet stores, we should focus on educating pet owners, veterinarians and physicians about zoonotic diseases.
The latest edition of CDC's Morbidity and Mortality Weekly Reports describes a case of rabies in a Michigan man from 2009. While human rabies in most developed countries is very rare, this is yet another reminder of the ever-present risk of rabies exposure in many regions, and the ongoing need to be proactive to avoid this almost invariably fatal - but almost completely preventable - disease.
In the 2009 Michigan case, the man woke one day with a bat on his arm. Bats are classic rabies vectors, and you have to assume that any bat has rabies until proven otherwise. If you can't be sure that you weren't bitten or scratched (something that may be easier said than done, because bats bites can be very tiny), then you have to consider yourself exposed if you've had contact with a bat and the bat wasn't tested and rabies-negative.
Unfortunately, the Michigan man did not seek medical attention, and nine months later he started to develop signs of rabies. It started off with pain and progressive numbness in his left hand and arm, and pain in his neck and back. He developed weakness in his left hand and soon could not grip anything or raise it more than a few inches.
While he was being evaluated in hospital, he developed breathing difficulties and had to be placed on a ventilator. Various diseases were considered and numerous tests were run. After a little initial improvement, he began to deteriorate, with more profound neurological signs.
Five days after he was admitted to hospital, his wife was asked about possible animal bites, but she didn't know of any. A couple of days later, a relative recounted being told about the bat encounter, but there was little that could be done at that point, and the man died three days later. Rabies was eventually diagnosed.
Because of the potential risk of exposure, 11 family members that may have had contact with the man's saliva received post-exposure treatment.
Sadly, you can almost guarantee that rabies could have been prevented if he had reported the bite and received post-exposure treatment (even months later). Rabies education is critical so that people know the risks of exposure and know to get medical advice after any encounter with a wild animal.
- Like all mammals, donkeys are susceptible to rabies virus but infections are not particularly common. Raccoon rabies has also be identified in the area, and a bite from a raccoon may have been the source.
- A York County woman was bitten by a kitten that ran into her house when the door was opened for someone else. The kitten bit her when she grabbed it to throw it (hopefully not violently) back outside... an understandable reaction but not what you want to do in a case like this. You need to know whether a wild animal that bites is rabid, and if it gets away, you can't test it. You need to get away from it but keep it contained until someone can come get it. The other problem with people getting rid of the animal is that they might not recognize the risk of rabies. In this case, the kitten was hit by a car after being removed from the house, which allowed for it to be tested.
Yet another report of a dog being exposed to rabies through contact with wildlife, then being euthanized because it was not properly vaccinated.
- An unvaccinated animal that has been exposed to a rabid animal has to be euthanized or undergo a strict six-month quarantine. A vaccinated animal only needs a 45-day observation at home.
- Encountering a manic bobcat isn't something I'd like to do, and a LaCrosse, Florida woman spent nine days in hospital after being attacked by one. The 25-pound cat was trying to get the family's cat, then lunged at the woman when she came outside the house, aiming for her neck. Her husband then shot it. They knew that the bobcat needed to be examined, and took the rather unusual approach of bringing it to the hospital emergency room with them (I'd love to have seen that). I don't imagine hospital personnel did anything, but Florida Fish and Wildlife Conservation Commission personnel came and got it, and later confirmed that it was rabid. (Image: Lynx rufus, US Fish & Wildlife Service)
Raccoons are fascinating critters but they don't make good pets. Their curiosity makes them quite disruptive and damaging, and they have seriously injured people (particularly infants). They are also rabies vectors, and in many regions raccoon ownership (along with other wildlife species) is illegal (or only legal with a license). Despite all this, some people continue to keep raccoons as pets, and injuries continue to happen. Unfortunately, it's often not the owners that suffer the consequences, but children.
A one-week-old Griggville, Illinois baby is in hospital after being attacked by her grandparents' pet raccoon. The baby was in a room with the raccoon (not a good idea to start with), when the raccoon starting biting and scratching the baby's face and head. The raccoon's owner thinks the raccoon wasn't being vicious, just curious and trying to get a ribbon off of the baby.
"Rampy was trying to get the bow off the baby's head and it's got long claws and he was scratching up the head trying to get the bow off," said the owner.
Regardless, the fact that it caused severe injury indicates it's a hazard. (Wounds caused by accidents heal at the same rates as those caused my malice.)
Euthanasia of the raccoon was requested to test it for rabies. The owner countered that it had been vaccinated against rabies and dewormed (which raises the question of what veterinarian did this. I'd consider vaccinating and deworming an illegal pet unethical at best). Further, rabies vaccination does not guarantee that the raccoon isn't rabid. A judge eventually ordered the raccoon to be euthanized.
You'd think the raccoon's owners would be aghast at the attack. While I can see how they'd be attached to their pet, typically concern over a grandchild takes precedence. Not here, however, as the owners fought the euthanasia order and are railing against local authorities for having the raccoon euthanized after a potentially life-threatening attack. Even the infant's father is taken back by their attitude, stating "If it was somebody's dog that bit a kid, they'd be held accountable. These people should be held accountable for [the raccoon]."
A New Jersey man managed to avoid being a good example of Darwin's "natural selection," thanks to the help of medical professionals and the Bronx Zoo.
Eric Bortz (who, I'm sad to say, works at a veterinary clinic), purchased three snakes - a copperhead (venomous), a timber rattlesnake (venomous) and a monocled cobra (venomous) - a couple of weekends ago. (Sadly, that's not hard to do if you have a few hundred dollars.) The snakes joined his collection of pets, including a tarantula, several scorpions, a king snake, a boa constrictor and a rabbit (no word whether the rabbit was a pet or a snake-snack).
Anyway, the following Monday, he was bitten by the newly-acquired cobra. He had apparently been told that the snake had undergone a procedure to render it non-venomous, but it became apparent that it either wasn't true or it wasn't done right, when Mr. Bortz went into respiratory distress and started seizuring.
Fortunately, he received prompt medical care and his proximity to the Bronx Zoo facilitated access to antivenin. Zoos are often called in to help out when people get bitten by their venomous snakes, since zoos typically keep a supply of antivenin in case their staff get bitten.
Keeping venomous snakes is just stupid - there's no reason to do it, and t puts people at risk. The risk is not just to the owners who made the choice to keep the animals, it's also to other people that might be exposed if the snake gets out, including family members, friends and neighbours, who didn't make the choice... it's something that has happened in the past, and will no doubt happen again. Venomous snakes (and other dangerous animals) are also a potential problem for first-responders if there's been a fire or other incident in the house. There's absolutely no reason for these creatures to be kept as pets, and no reason that keeping and selling them shouldn't be met by large fines or other deterrents.
A recent news report from Berkshire, Massachusetts that was highlighted by ProMed is a strange and concerning story of rabies exposure.
The story involves two people that were stalked and attacked by an aggressive fox. One man was attacked in his driveway. He fought the fox off with a smoker lid, but several hours later it attacked and attached itself to a woman next door who was outside collecting her recycling bin. The fox bit her multiple times, and it took 20 minutes (with the aid of the same smoker lid - apparently a good fox extractor) to remove the fox from the woman’s leg. The man then killed the fox.
The woman’s sister called the police, who dispatched paramedics and suggested they call Animal Control to get the fox tested for rabies.
So far, so good. Unfortunate attack but managed as well as can be expected.
Anyway, when the paramedics arrived, they told the woman that she didn’t need to go to the hospital. A little more information in the article would have been nice here. Based on the severity of the injury, the response of the paramedics probably makes sense. The fox had bitten her, but the bites didn’t appear to be too serious from a trauma standpoint, and racing her off to the hospital in an ambulance was not required. However, rabies exposure is a major concern and this scenario raises a good question: What is the role of paramedics in thinking about and educating people about the risk of rabies exposure? Ideally, paramedics should know enough to tell people that they should seek medical care when there has been potential exposure to rabies. I don’t know whether this is the case, however. If someone isn’t injured enough to require emergency care, is that all that the paramedic needs to assess?
The woman then had a relative drive her to the emergency room. If this was because of concerns about the severity of bites, then that makes sense. If it’s from a rabies exposure standpoint, then it’s overkill. Assessment of rabies exposure and starting treatment is considered a medical "urgency," but not an "emergency." Basically, that means you don’t need to be treated immediately and you have time to go to a regular physician. In this case, going to her physician the next day would have made the most sense, since emergency rooms are not the ideal place for rabies assessment and exposure treatment.
The fox was rabid in the end, and the woman was started on rabies post-exposure treatment. Even if this was an inefficient way of getting care, the key point is that she was treated. Rabies is almost invariably fatal but is almost 100% preventable with proper post-bite care.
The description of her treatment is strange, however. “On Monday she began the lengthy series of anti-rabies vaccinations, which included injections into each bite mark. She returned to the hospital for another shot on Thursday and learned that she has 10 more vaccinations to endure this month, with each hospital visit at a USD 75 co-pay.” This makes no sense. Current-day rabies post-exposure treatment consists of a series of 4 doses, not 10 or more.
Another strange part of this story is the apparent difficulty the two victims had getting the animal tested. The people who were attacked claim “I called a rabies hotline and nobody picked up." As a result, the fox's body sat on the woman's property for three days until they took it to a local vet clinic, that shipped the fox’s body for testing. In another strange twist, it seems the woman had to pay for testing herself. That makes absolutely no sense. This is clearly an animal with a high likelihood of having rabies and a situation where there has been clear exposure of a person. The rabies status of the animal must be determined and requiring people to pay for that themselves makes no sense.
By the time I posted this story, the Berkshire newspaper had pulled the article from its website. I don’t know why. It could because the story was poorly written or the information was incorrect. Regardless, it raises some interesting issues.
A Royal Oak, Michigan resident is undergoing rabies post-exposure prophylaxis after being bitten by a rabid cat. The person found a sick cat by the side of the road and took it to a vet clinic... a good deed in theory, but problematic in many ways. One obvious risk is the potential for rabies exposure, as occurred here. The cat was subsequently diagnosed as rabid, and having been bitten the good samaritan was clearly exposed. Fortunately, the veterinarian kept the contact information for the person who dropped off the cat, who can therefore now receive the necessary treatment.
Associated with this event, the Royal Oak Animal Shelter has issued the following reminder:
- Do not approach any animal if it appears sick. Call the Police to get animal control involved.
- Tell your children to stay away from any stray animals, whether they are skunks, dogs, or cats. Any of these could be infected.
- Vaccinate your dogs for rabies. It is the law.
- If you let your cats outside, STOP doing so. If you can't stop, please make sure your cats are vaccinated for rabies.
- If they already have been vaccinated, talk to your veterinary professional about having a booster administered to protect your animal. There is no cure for this deadly disease.
Heart attacks? Sure.
Mechanical problems? Absolutely.
Aggressive passengers? Yes.
But a 12-pound dog? Apparently so.
Mandy and her owner were flying from Newark to Phoenix on a US Airways flight. The dog was sedated and in an airline-approved cage under the seat, as per airline policy. So far, so good.
Then the dog started to become agitated. One report suggests it was because the sedation was wearing off. Whatever the cause, the owner tried to take the agitated dog out of the protective confines of its cage, into a noisy, crowded and potentially frightening new environment. Not surprisingly, when you take a dog coming out of sedation (and perhaps not completely aware of what's going on) and put it in a unfamiliar and confusing environment, bad things can happen.
In this case, it resulted in the dog biting the passenger in the seat next to the owner (who was trying to help calm down the dog). The dog then got loose and ran up and down the aisle of the plane, barking. A flight attendant who tried to grab the dog was also bitten.
The bites were minor, but the pilot decided to divert the flight to Pittsburgh so the bite victims could be treated (and presumably to get the dog off the plane before it bit more people). The people who were bitten eventually got back on board and continued the flight. However, Mandy and her owner did not, as "separate transportation" was arranged for them.
There's no information in the reports I've seen about the dog's rabies vaccination status, something that was hopefully queried by medical personnel. There's also no information about whether any action will be taken against the dog's owner. If the airline (and/or passengers) wanted to, I imagine a lawsuit could easily follow (especially given the litigious nature of US society). They might win, too, since the dog's owner deliberately broke clear rules that say the dog must remain in the carrier at all times. As a result of her action:
- Two people were injured.
- Medical costs were incurred.
- The plane had to be diverted, probably resulting in a large cost to the airline for additional landing fees, fuel, personnel time, and perhaps the need to move flight personnel or postpone flights because of the diversion. (I'd love to know an estimate of what such a diversion actually costs.)
- 122 passengers were inconvenienced and might have incurred costs from the delay as well.
...all for something that could have been avoided by leaving the dog in its cage.
The US Agency for Healthcare Research and Quality has published data regarding emergency department visits and inpatient stays involving dog bites. The comprehensive data from 2008 don't provide any real surprises, but they demonstrate yet again the importance of dog bites and the need to take further steps to reduce their incidence.
Among the highlights:
- There were approximately 316 200 emergency department visits due to dog bites in 2008, with 9 500 people requiring hospitalization.
- On average, 866 people visited an emergency department and 26 were hospitalized from a dog bite every day.
- Bites requiring emergency visits or hospitalization were much more common in rural areas, and males were more commonly bitten than females.
- Children 5-9 years of age had the highest rates of emergency department visits due to dog bites, while hospitalization rates were highest for 65-84 year-olds.
- The average cost of a dog-bite-related hospital stay was $18 200. More than half of people hospitalized required surgery.
- 0.5% of people hospitalized for a dog bite died.
This report involved hospital record data only, so there was no way to assess why the bites happened. Not all bites are preventable, but a lot are. When you consider the huge impact of these injuries, both physically and economically, it's clear that we have to do a better job preventing bites.
A dead otter was found floating in a pond in Florida near the site of a recent otter attack that was captured on video. Testing confirmed that the animal was rabid. It's impossible to determine whether this is the same otter that attacked the teenager in Boca Raton last week, but it's likely, and shows that rabies post-exposure treatment of the victim was a good decision.
Numerous rabid otters have been identified in Florida in recent years. I haven't seen any information about the viral types that have been involved or how it is thought that otters are becoming infected. Regardless, these incidents should be a reminder to stay away from wildlife, and to consider rabies exposure any time someone has been bitten by a wild mammal.
A nine-month old Georgia (US) baby is in critical condition after being attacked by two raccoons while sleeping in her crib. The attack occurred in the middle of the night, and the baby ended up with severe bites over her head and other parts of her body.
It's not clear at this point whether these were pet raccoons that were being kept illegally or whether two raccoons broke into the house. If the latter, it's suspected that the family may have been feeding the raccoons, which could have made them less fearful of people than usual. The news clip also shows a large cage outside that could presumably house raccoons (pure speculation on my part here). Authorities are investigating whether these were illegal pets, and if so charges could result.
An unprovoked raccoon attack in a house is pretty strange. Raccoon attacks would be more likely in the raccoon's environment or if they were sick (e.g. rabies). They might also be more likely to try to break into a house if they have been fed by people and lost their fear of humans. Still, attacking a baby seems like a very strange thing for them to do. I also wonder whether an attack like this might be more likely with a pet raccoon, especially if it was an older, established raccoon in a household where a new baby had disrupted the routine.
Rabies has to be a major concern in a situation like this. One of the raccoons was killed by police. The news clip and article on the same website provide conflicting information about whether the other raccoon was caught. Both raccoons need to be tested to determine whether they had rabies. Otherwise, the baby will need rabies post-exposure treatment.
A Florida woman is facing criminal charges after biting someone at a vet clinic. Kathleen Minneker took her two dogs to the Affordable Animal Care Clinic in Fort Myers, Florida, for grooming. She showed up an hour late and became irate when the grooming wasn't finished on time. At that point, Ms. Minneker apparently lost it, and attacked clinic owner, Gina Brashear, who ended up covered in bites, bruises and scatches. Brashear explained "a chunk is gone off my finger and a chunk off my toe." All this was from the irate customer, not the dogs. In a bit of an understatement, Brashear said "She's a biter."
Brashear is now receiving antibiotics to prevent bite-associated infection, something that can result from human bites just like from animal bites.
There's no word on whether Ms. Minneker was up to date on her rabies shots. Unlike a dog, Ms. Minneker will not be quarantined for 10 days to make sure she does not have rabies, however she may end up with a somewhat longer confinement period courtesy of the State of Florida.
A Wisconsin man is recovering after being attacked by a seven-year-old Siberian tiger at The Wisconsin Big Cat Rescue & Educational Center. The victim is a volunteer at the centre, and he was attacked while giving the tiger some water. He was airlifted to hospital but his injuries are described as minor.
As is often the case, it is suspected that the attack wasn't an indication of aggression. Rather, it may have been playful behaviour, something that can quickly become deadly with a large cat. People have been killed before by big cats trying to play with them - all it takes is one misplaced swat from these extremely powerful beasts to do significant harm.
Attacks by big cats are not exactly rare in North America, and are almost always associated with poorly housed "pet" big cats and roadside zoos. It is actually relatively easy to buy a big cat, and many parts of North America have few to no restrictions on ownership. The animals often suffer because of inadequate nutrition or poor housing, and public health is at risk because of inadequate housing and restraint. There's no reason for tigers to be in North America apart from accredited zoos (or similar facilities) with adequate housing for these large animals and properly trained personnel. They are not pets. You can hand raise a tiger and make it pretty tame, but they are never safe. How many cat owners are bitten, swatted, stalked or jumped on by their small-sized pet cats every day? Imagine what happens what those same feline behaviours are exhibited by a tiger that weighs a few hundred pounds.
When I first saw the headline, I thought "here's another person injured at some crappy roadside zoo that has no business keeping big cats." This facility and the circumstances around the attack seem to be different. This does seem to be a legitimate rescue facility (some "rescue" facilities for various species are just people who like to collect animals), although it's hard to say too much about how reputable the place is from a distance, and whether there is any truth to some unflattering internet reports. The attack also occurred through a fence. In properly run facilities, the likelihood of an attack is reduced by restriction of direct contact between people and cats. If someone isn't in a pen with the animal, the chances of injury are much lower. Circumstances regarding this attack aren't clear, so it's hard to say whether there are issues with the design of pens or how people interact with the animals, and whether the person really wasn't in the pen. However, the fact that this seems like a more reasonable facility than your average small zoo and a potentially serious attack still occurred underscores the danger posed by people owning these animals.
ProMed's monthly rabies update contains some recurring themes:
- A couple of incidents of dog versus rabid raccoon. The dog usually comes out on top, but the raccoon can exact revenge at the end of the day through the need for quarantine or euthanasia. If the dog is not vaccinated, a long quarantine or euthanasia is required. If the dog is vaccinated, only a shorter observation period is needed.
- A rabid skunk was found wandering around during the day with a wobbly gait and drooling. Any wild animal that is acting strangely should be considered rabid until proven otherwise. They don't have to be showing signs of severe neurological disease. Something as simple as not being afraid of people or wandering around in areas or at times when they would not usually be found should raise the suspicion.
- A child who was sleeping outside woke up to "find a raccoon, kind of, scratching at his leg." (I assume they mean it was "kind of scratching at the kid's leg," (whatever that means), instead of it was "kind of a raccoon.") The raccoon wasn't caught for testing but the child is undergoing post-exposure treatment because a normal raccoon wouldn't be expected to do that, so there is a significant chance of rabies exposure. Scratches are not high risk since rabies virus does not live in the claws, however it is possible that saliva from the raccoon could have been present on the animal's feet or the raccoon could have licked the child before scratching, such that the scratches could have then inoculated rabies virus into the tissues.
- A couple of reports of rabies in rabid kittens. These cute little rabies vectors cause repeated problems, and lead to public alerts notifying anyone who may have handled the kittens to get evaluated to see if they need post-exposure treatment. Handling of strays should be avoided.
- A family received post-exposure treatment after being bitten by their rabid cat. Vaccination of pets is not just for the health of the pet. It's to reduce exposure of people as well.
The woman was admitted to hospital with a fever, headache, neck stiffness, confusion, difficulty speaking and nausea. These signs are suggestive of meningitis and a spinal tap was supportive of that presumptive diagnosis. Blood samples were also taken, and the same bacterium, Streptococcus zooepidemicus, was isolated from both blood and spinal fluid, confirming a diagnosis of S. zooepidemicus meningitis. She was treated and improved, but did not fully recover.
Streptococcus zooepidemicus is primarily associated with horses, although it can occasionally be found in other species such as dogs. After the diagnosis, the woman's family was questioned about her hobbies and it was revealed that she was an avid horsewoman. Further, she had been bitten by her horse the previous week. That was the presumed source of infection, but it doesn't appear that any further investigation was undertaken.
Associating the meningitis with the bite is reasonable, but it's not definitive. Streptococcus zooepidemicus infections in people have occurred in the absence of bites or other clear sources of exposure to horses, so the bite wasn't necessarily the problem. Regardless, it indicates the need to be proactive and properly treat any horse-associated wound, be it a bite or any another wound that gets contaminated with bacteria from the horse or its environment.
This was a very unusual case. People shouldn't be overly concerned about getting S. zooepidemicus meningitis from their horse. However, it should serve as a reminder that bad things can happen periodically and that proper attention to general hygiene practices and bite wound care is always important.
On a side-note, I thought the title "A horse bite to remember" was a bit crass, since the woman is now unable to live independently because of severe amnesia (memory problems) as a result of the infection. Maybe they were trying to be ironic, but it seems below a journal such as Lancet.
This Worms & Germs blog entry was originally posted on equIDblog on 10-Oct-10.
The family of a Washington state man is suing a dog owner after the man was bitten and developed a fatal infection. News reports are somewhat sketchy and contain some inconsistent information, but it appears that Kenneth Bock was bitten by Buddy, a coon hound, at his place of work. There are conflicting stories about how the bite occurred. Some reports say that the dog was roaming freely, while the owner's lawyer says Mr. Bock was bitten while reaching into the vehicle where Buddy was sitting. Apparently, the dog had bitten someone else at the same business earlier that day, so it's clear this dog and/or its owner had some issues. Regardless, the bite occurred and blood was drawn, but at the time the bite seemed to be minor. However, Mr. Bock developed a severe infection and died a week later.
Buddy was euthanized a few days after the bite. That in itself is an issue, because any dog that has bitten someone needs to be observed for 10 days to ensure it does not show signs of rabies infection or, if it must be euthanized within 10 days of the bite, the dog needs to be tested for rabies after euthanasia. Mr. Bock was still alive at the time Buddy was euthanized, so Buddy's rabies status should have been confirmed by observation or testing. Any veterinarian euthanizing an animal is required to ask whether the animal has bitten anyone in the last 10 days. None of the reports say whether or not the dog was tested.
The news reports also don't provide much information about the infection. They say that the Mr. Bock had another medical condition that put him at increased risk for infection. It could be that he had lost his spleen and he developed an infection with Capnocytophaga canimorsus. This bacterium, which is present in the mouth of most dogs, almost exclusively causes disease in people that have had their spleen removed (as well as alcoholics) and rapidly fatal infections can ensue. There are also a variety of other conditions that affect the immune system and which can thereby put someone at higher risk for various bacterial infections.
Even innocuous-appearing bites can be bad news. People need to protect themselves from bites, and know what to do if a bite occurs.
- Make sure you know if you are in a high-risk group. If you have a compromised immune system, which includes having had your spleen removed, you need to be aware that you are at particularly high risk for severe complications of any bite. Any high-risk individuals who are bitten should seek prompt medical care.
- Be careful around dogs. This is particularly true for dogs you don't know, dogs that have a history of being aggressive, and dogs that are in a confined space like a car. They may perceive this as a "den" and interpret someone new near them as an intrusion into their space.
- Use common sense if you own a dog that has shown ANY tendency to be aggressive. An aggressive, territorial or fearful dog is not a dog to be taking out in public. Any aggressive tendencies must be addressed immediately.
- Don't take pets to stores. You never know who will be there. There may be people who are very allergic or fearful of dogs. Even if you have the nicest dog on the planet, not everyone wants to be forced to be around it.
What happens when you combine a festering toe wound, a doctor-averse person, a dog and a lot of alcohol. Well, I guess you get Jerry Douthett and his dog Kiko, a Jack Russel who is being called a "lifesaver" for gnawing off Jerry's infected toe.
Apparently Mr. Douthett had what he believed was a small sliver in his toe a few months earlier. He picked away at it for a while, later using a knife to trim away infected tissue. The toe became so inflamed that he couldn't wear shoes. Eventually, he decided to numb the pain and his fear of doctors with a large volume of alcohol. After having 4-5 beers at a local restaurant, he downed two giant margaritas, then passed out after his wife drove him home. His wife explained "Jerry had had all these Margaritas, so I just let him sleep, but then I heard these screams coming from the bedroom, and he was yelling, 'My toe's gone, my toe's gone!'"
Indeed it was, or at least most of it. "The toe was gone," he said. "[Kiko] ate it. I mean, he must have eaten it, because we couldn't find it anywhere else in the house. I look down, there's blood all over, and my toe is gone."
After the Jack Russel relieved Jerry of most of his big toe, Jerry ended up finally going to the hospital. Doctors confirmed that the rest of the toe needed amputation and the infection (which had reached the bone) was probably the result Type II diabetes.They removed the rest of the toe and treated the infection.
Jerry's not upset with his dog. Rather, he's grateful that Kiko's snacking made him go the the doctor, which led to him finally being diagnosed with diabetes which can now be properly managed. The dog is under a 10-day quarantine for rabies observation, as would happen with any dog bite.
People with diabetes are at high risk for various types of infections. I've heard of diabetics with serious foot infections that developed because their pets were licking foot wounds or chewing on their toes. Diabetics can have decreased nerve sensation and sometimes don't notice when their pet is doing damage by licking or chewing.
Diabetes is not a reason to avoid pets, but the increased risk of infection means that extra care needs to be taken to reduce the risk of infections caused by pets, particularly from pets licking wounds directly and from people indirectly spreading bacteria from a pet to a wound. Simple, logical preventative measures around pets and good attention to hygiene are important.
Not drinking yourself into a stupor also helps.
- Roaming pets + wildlife = bad news: One person's dogs killed a raccoon while out for their "romp around the yard." The raccoon was rabid. There's no mention about the vaccination status of the dogs. If they were vaccinated, they probably got a rabies booster and are under a 45-day "house arrest" for observation. If not, they either need to be placed under a strict 6-month quarantine at a separate facility, or they'll be euthanized. Another report describes a different dog that is now under a 6-month quarantine after attacking a raccoon. In yet another report, a North Carolina woman's dog was euthanized because it killed a rabid fox and was unvaccinated (the owner chose euthanasia over quarantine). That dog is now dead mainly because the owner didn't take the simple and relatively inexpensive step of ensuring that her dog was vaccinated.
- Pissed-off wildlife bite. Sometimes they're rabid too. Get too close at your own peril: A South Carolina man is undergoing post-exposure treatment because he was bitten by a raccoon while removing it from a trap. I'm glad that he had the animal tested. It's pretty easy to see someone in a situation like this just yelling at the raccoon and letting it go, thinking they were bitten because the raccoon was upset and not realizing that they might have been exposed to rabies.
- Some people just don't get it: In response to rabies exposure of close to 50 church members from a rabid bat while on a mission trip, the mission leader stated "It's just part of being in rural America, so there's really not a lot to talk about." Ugh. Rabies exposure should not be written off as some benign, unavoidable rural American experience. It's exposure to an almost invariably fatal disease that requires a series of expensive treatments. It's also not a rural thing. Rabies exposures can occur commonly in urban areas as well.
- Stray kittens can be cute but deadly: A rabid cat and kitten were identified in Ocean City, Maryland, and authorities are looking for people that may have come into contact with them. Human exposure to rabies from handling cute but infected kittens is not uncommon, and sometimes involves a lot of people. If you see a stray kitten, it's best to leave it alone. If you feel the need to rescue it, make sure that you get it to a vet for an exam, and that it subsequently goes somewhere where it can be properly observed and taken care of. If you're bitten in the process, make sure the kitten is quarantined for 10 days to see if it's rabid, or euthanized and tested. The worse case scenario is when people play with stray kittens, get nipped in the process, dismiss it as a minor or playful bite, then release the kitten back into the wild, never knowing whether they might have been exposed to rabies.
Former British pop star and I’m a Celebrity-Get Me Out of Here reality TV character Samantha Fox was bitten by a rabid cat while vacationing in Thailand. Fox was feeding stray cats near a restaurant and was attacked.
Having contact with stray animals is a high risk activity, particularly in regions where rabies is very common. When traveling, it’s important to understand the infectious disease risks in the areas you visit, and rabies is one of them. A bite by a stray animal is usually going to be considered a potential rabies exposure, unless you’re in a rabies-free country or the animal is available for observation or testing. That’s not usually the case, and post-exposure treatment, consisting of a shot of anti-rabies antibody and a series of 4 rabies vaccinations, is usually required.
Fox wasn’t particularly impressed by the treatment: "The treatment for rabies makes you feel sick and horrible, though, really fluey and shaky." Usually, the post-exposure treatment isn't too bad (I can speak from experience here) and current rabies vaccines tend to have a much lower rate of side effects than older vaccines. Fear of adverse effects shouldn’t be a deterrent to proper treatment of this almost invariably fatal disease.
- 61% of attacks occurred while the guide dog was harnessed and working with an owner or trainer.
- Labrador Retrievers and Golden Retriever/Flat-Coated Retriever crossbreeds were more commonly attacked than other guide dog breeds. This was disproportionate to the percentage of guide dogs that were these breeds, so it wasn't just a factor of more Labs being guide dogs so there were more to be attacked. I'm not sure why these breeds would be attacked more often.
- Most (97%) attacks occurred in public places: 26% occurred in town centres and shopping areas, and 23% occurred in public parks or exercise areas.
- 43% of attacks were considered unprovoked.
- Most (61%) of attacking dogs were off-leash and with their owners. The surprising thing to me is that 23% of attacking dogs were leashed and with their owners. 15% were roaming free.
- 38% of attacking dogs were bull breeds, which is much greater than the percentage of the general dog population that is made up of bull breeds (5.9%).
- 41% of attacked guide dogs required veterinary care.
- In 19% of attacks, a person was also injured.
- After 45% of attacks, the working performance and behaviour of the attacked (guide) dog changed. Over half of these were reported to be fearful, nervous and wary, or to display a lack of confidence. Two dogs had to stop working as guide dogs.
- The attacking dog's owner was charged in 31% of incidents.
It is clear that attacks on guide dogs can result in major problems. These include injury to the dog, injury to the handler, impacts on the performance of the dog as a guide and impacts on the emotional status of the owner. Dog bites are too common and bites from incidents like these, which occur in public places, are largely preventable with responsible ownership. Unfortunately, there are too many irresponsible dog owners out there. The threat of more serious financial penalties may be the only way to change some peoples' behaviour.
A UK man is recovering from a tarantula bite that occurred when he, apparently in a drunken stupor, encouraged the venomous critter to bite him. (I suspect the "victim" has a pretty high endogenous level of stupidity, because I don't think you could get me drunk enough to say "Hey, maybe I should let an enormous venomous spider bite me!")
The character in question, Peter Saunders, stated "It was completely my own fault. I provoked the spider into biting me on my index finger so I can't complain about the consequences at all." At least the statement demonstrates some degree of logical thought. He ended up getting more than he bargained for, since the bite was a lot more painful than he anticipated. The day after the bite (presumably along with a massive hangover), Mr. Saunders' arm went numb and he was given various antibiotics to help treat a suspected secondary infection.
Unfortunately, the moment of clarity represented by his understanding that it was all his fault passed quickly since "... this incident has not put him off keeping these pets and he is considering buying more exotic creatures in the future." Let's hope he doesn't decide to see what it feels like when an African lion chews on his throat.
Photo: Fort Hall Baboon Tarantula (source: www.lotsalegs.tenczar.net)
Another tragic dog bite incident has resulted in the death of a three-week-old baby in Quebec. The baby's mother (17) and grandmother (37) left the child alone in the house, strapped to her car seat on a chair, while they went outside for a smoke. There were also two Huskies loose in the house at the time. Although the women were only a few meters from the open door, and came back inside when they heard noise, by the time they reached the baby it was already too late. The paramedics found the baby "covered in deep bite marks and scratched.
It is unclear to whom the dogs belonged, as the mother and father of the baby were sharing the house with two other people. The baby's father (who was not home at the time of the attack) said that the dogs had been around ever since the baby was born and had never posed a problem. The dogs were not normally aggressive and "when strangers came to the door, they didn't even bark." He said "there was no sign that this could happen."
Dog bites are always bad, but in the case of small children in particular they can even be fatal. According to Statistics Canada, since 1990 there have been 28 fatal dog attacks in Canada, and 85% of those killed were children under the age of 12.
Dog bites often occur when people don't know how to behave around a dog, and dogs may bite out of aggression, fear, or rough play. A three-week-old baby strapped to a car seat would pose little threat to a Husky, and unfortunately we will likely never know what brought on the attack. Parents and family members need to realize that a new baby is a big adjustment for everyone in the household - and that includes pets. A dog that is normally "as good as gold" may react very differently to a small, wriggling, strange-smelling, crying baby that suddenly takes over part of the animal's home "territory." It is very important that pets and babies be introduced very carefully and slowly, and they should always be supervised. Dr. Enid Styles, a veterinarian and behaviourist, makes some very important points:
...Styles said it is possible the animal might have been startled by the child's crying or the baby might have been caught in the middle of a fight between the dogs.
In any case, a child should never be left unattended around dogs...
"Supervision needs to mean, really, that you are between your dog and your child," she said. "You can't be just on the other side of the room."
Both Huskies have been seized by the Humane Society, and tests will be done to to confirm which of the animals was responsible for the attack and whether it was suffering from any problems, such as rabies (which presumably means the dog will be quarantined for 10 days). It is likely that the dog responsible will be euthanized.
Photo source: www.cbc.ca
Recent reports of a woman in Texas that "contracted rabies" are great examples of less-than-careful reporting. The headlines look dramatic, and a couple of articles state that a woman bitten by a puppy "contracted rabies", but it's far from the truth.
Here's the real story, as far as I can tell:
- A litter of stray puppies was taken to a shelter and then sent to a foster home.
- The woman who took them in was bitten in the leg.
- She received medical care and took the puppy to a vet. The vet euthanized the animal because of the aggression it was displaying and had it tested for rabies.
- The puppy was positive for rabies and the woman is undergoing post-exposure treatment.
It's not a nice situation for the person that was bitten, but it's not exactly a rare event and post-exposure treatment for rabies, when given properly, pretty much has a 100% prevention rate.
Authorities are also trying to track down any people that may have had contact with the puppies before they were taken to the shelter, to determine if more people need post-exposure treatment.
Strangely, the other puppies are being isolated for 45 days, after which time they will be put up for adoption (assuming they don't develop signs of rabies). This doesn't make a lot of sense. Standard recommendations are that unvaccinated animals exposed to a rabid animal should be euthanized or quarantined for 6 months. The 6 month quarantine is in place because rabies can take a long time to develop after exposure. Since these puppies came in with the sick one, and it's almost certain there was no information about their vaccination history, they have to be considered exposed and unvaccinated. This is true even if they were vaccinated at the time of arrival because they could have been exposed before vaccination. Further, animals are not considered protected until 28 days after vaccination, and exposure within 28 days of the first shot is the same as exposure of an unvaccinated animal.
In this case, it was pretty easy to determine that the woman didn't have rabies in some, but not all of the articles. I particularly liked how one of the stories described how rabies "eats away at the brain," a description you wouldn't expect to see from a more mainstream source.
Presumably, the woman who was bitten will be left with nothing more than some bad memories and an increased awareness of rabies. Hopefully the shelter reviews its policies to determine whether this could have been prevented and whether other measures should be in place to reduce the risk to people who foster animals. At a minimum, this would include ensuring foster homes know about the risks, know to get the animal to a veterinarian if it begins to act strangely (as this woman did) and ensure that other pets in the household are properly vaccinated.
Argentinian soccer star Diego Maradona has had quite a life, including the famous/infamous "hand of God" goal, drug addiction, gastric bypass surgery and a tumultuous coaching career. You can now add "beaten up by a small dog" to that list. Maradona was discharged from a Buenos Aires clinic a couple weeks ago after undergoing recontructive surgery to his upper lip, after being bitten by his pet Shar Pei. It's not clear exactly what precipitated the bite, but apparently he commonly "gets close" to his dogs before bed. Hopefully Maradona figures out what caused the bite.
Dog bites are surprisingly and disappointingly common.
They are not usually random events.
There's usually a cause. It might be related to the dog, the person who was bitten, or both. No bite should be considered acceptable, even though bites are common. Every bite should be investigated. Potential inciting factors should be identified and measures should be taken to reduce the risk of this ever happening again. Sometimes, a cause is clear (for example, if a person threatens a dog and it tries to defend itself). At other times, the reason for the bite may not be as obvious. Sometimes, dogs bite for behavioural reasons (e.g. aggression, fear). Sometimes, dogs bite for medical reasons (e.g. pain, decreasing vision). Sometimes, dogs bite because people act inappropriately around them. Differentiating these, and intervening whenever possible, is important and must be considered after any bite.
Dog bites are nothing new. They are extremely common and it's not unusual to see reports of serious, even fatal, dog bites, especially in children. There have been a few reports lately that are worth mentioning.
A Pennsylvania boy was seriously bitten on the face after being invited to pet a dog at a school function. The fact that the bite occurred during what we would consider an appropriate interaction, after being invited to pet the dog by the handler and under supervision, is notable. What's more concerning is the dog was at a booth set up by an organization that trains service dogs. Let's hope this group has reviewed their temperament testing and training protocols (the lawsuit might help spur that on).
A Custom's dog bit a young girl at Dulles Airport in Washington DC. The dog was in a training exercise in the baggage claim area and bit the child in the abdomen, requiring 20 stitches. This is very surprising for a dog that would presumably have been very highly trained and evaluated. Again, a review of their training program, the circumstances of the bite, the dog's history (whether it's shown any tendency to aggression before) and the handler's actions need careful review.
A 10-day old baby was bitten and killed by the family's husky. Little information is available but this reinforces the need to take care when introducing a new baby (or dog) into the household. This would have been an unprovoked attack, considering the age of the baby and the fact that it wouldn't have been moving around and potentially disturbing the dog.
A Hamilton, Ohio woman was attacked by a dog while locking her car, receiving injuries to her ankle and thigh. Neighbours needed to help get the dog off, indicating this was a real attack, not a nip from a startled dog. The dog is still at large.
Everyone needs to be aware of the risks of dog bites. That includes dog owners and people who never plan on having a dog, because you never know when you'll be in a situation where a bite is possible. Dog owners need to recognize the potential severity of bites, and ensure that their dogs are properly trained and controlled. Parents, in particular, need to ensure that their kids know how to act around dogs (whether or not they own a dog) and make sure they supervise their children closely when around dogs.
"Be A Tree" is part of the Doggone Safe Bite Prevention Program that teaches kids (primarily elementary school level) how to reduce the risk of being bitten by dogs in everyday situations. For more information, go to their website www.doggonesafe.com, or the Doggone Crazy website, www.doggonecrazy.ca.
A Phoenix, Arizona man is suing a pet store after he contracted rat bite fever from a rat he had purchased. It's not surprising to see a lawsuit following a serious illness, considering people in the US often try to sue for just about anything, but I'm not sure it won't get very far. I don't doubt that the man had rat bite fever, or that he got it from the rat he purchased - the question is, is the pet store really liable? Specifically, did they do anything inappropriate?
"Rats being sold to people should not have rat-bite fever," Heitzman's lawyer, M.E. "Buddy" Rake Jr., tells New Times.
Actually, the rats don't have rat bite fever... rats are healthy carriers of the bacteria that cause rat bite fever. There are two different bacteria that can cause the disease, Streptobacillus moniliformis and Spirillum minus. Streptobacillus moniliformis is presumably the cause here since it's the main cause of rat bite fever in the US. This bacterium is very commonly found in healthy rats, with upwards of 100% of healthy rats being carriers. You have to assume that every rat is carrying this bacterium.
"It wouldn't be any different if they sold someone a dog with rabies," he says. "I'm not in the nuisance-lawsuit business - he was in rough shape."
It would certainly be a different story if the store sold someone a dog that had signs of rabies. It's possible that someone could buy a dog that had been exposed to rabies but which was healthy at the time of sale, but that's pretty unlikely. However, a big difference is that there is a highly effective vaccine against rabies. There is no such thing for rat bite fever. If a pet store sells an unvaccinated dog of unknown origin that could have been exposed, despite knowing the need for rabies vaccination, there certainly could be liability issues. Selling a rat that is carrying a bacterium that we assume most or all rats carry anyway is different.
PetCo did not immediately return telephone calls this afternoon, but in its defense, there is an information pamphlet explaining exactly how to avoid contracting rat-bite fever available on the company's Web site. ...though it seems the pamphlet's best suggestion is to not get bitten in the first place.
It would be better if everyone who bought a rat was given the information sheet, but it's a start. The fact is, the best way to avoid rat bite fever IS to avoid getting bitten by a rat! Proper rat handling is a very important aspect of disease prevention, since you can never rule out the possibility that a rat is a carrier.
Our suggestion: Don't have a disgusting rat for a pet.
Whoa. Rats can make excellent pets. They can also carry infectious diseases. However, EVERY animal can carry infectious diseases, and rats are probably no more risky than most other domestic pets. The key is to take common sense precautions to reduce the risk of injury and infection (though the risk can never be completely eliminated). For rats, this includes selection of a rat that is not aggressive or fearful, knowing how to properly take care of a rat, knowing how to take care of a bite should it happen and being aware of some diseases for which you might be at increased risk because you own a rat.
Image source: http://commons.wikimedia.org
Pet bites are a big problem. Dogs bites in particular are far too common and can result in serious injury or even death in a small percentage of cases. Bites from other pet species also happen, but the extent of the problem is not clear. A good general rule is if it has a mouth, it can bite.
Another good general rule is if it has numerous sharp teeth, is a carnivore and your as upsetting it, you should get your hand out of the way. Pet store owner Dave Brown found this out the hard way, although in this situation he has the dubious distinction of having been bitten by a fish.
It seems that Mr. Brown was trying to catch a piranha that he was selling. I would have thought the standard way of catching a fish, not to mention a six-inch-long carnivorous fish, would be to use a net. Apparently not. Mr. Brown used his bare hands, and after a couple unsuccessful attempts to catch the fish, the piranha fought back, sinking his teeth into the store owner's thumb. The bite was severe enough that stitches were needed. According to Mr. Brown "There was blood everywhere. Every time I had him in a plastic bag the fish would bite through it. He was quite a feisty one." Personally, I think if a carnivorous fish was repeatedly trying to attack me through the bag, I'd probably change my approach to catching it.
According to a local fish expert, "[Mr. Brown] was very unlucky as these fish normally just attack when they're hungry. It may have been a bit peckish."
Fortunately, apart from a sore thumb, it sounds like the biggest problem Mr. Brown will face is the harassment that I assume he's going to take from friends after being bitten by a fish.
A five-year-old Oklahoma boy is recovering after being attacked by a beaver. Beaver and attack aren't two words that you usually put together, but in this case the boy went to pet a 60 lb beaver that he saw outside and it proceeded to attack him, taking a "chunk out of his calf" in the process. The beaver was killed with a crowbar.
This is a pretty unusual situation. Beavers aren't known for attacking people, which should raise some red flags right there. Rabies should be considered in any mammal that acts abnormally. An aggressive act by a species not known for unprovoked attacks would certainly count.
The boy's mother went to "great lengths" to get the beaver tested for rabies. I'm not sure why great lengths were required since this was a bite from an abnormally-behaving wild animal in a rabies endemic area, but it's great that she was aware of the problem and acted accordingly. While the outcome was unfortunate for the beaver, the family is lucky that the beaver was killed and available for testing. If it had gotten away, they would have had to assume that it was rabid, meaning the child would need rabies post-exposure treatment. That's expensive and somewhat unpleasant (two initial shots and 3-4 boosters) but virtually 100% effective at preventing rabies (and since rabies is almost always fatal, it's a necessary procedure).
This report highlights a two key points:
- Leave wildlife alone.
- If you are bitten by a wild animal, make sure rabies is considered. It's very rare but fatal when it occurs, so you don't want to take any chances.
A report from Seattlepi.com is a textbook example of what can happen to certain people after dog bites. Mike Moore tried to break up a fight involving his two dogs and received a minor bite. It barely broke the skin. No big deal, eh? Well, perhaps for most people, but unfortunately not for Mr. Moore.
He cleaned the wound and didn't think much about it. Two days later, he thought he had the flu. The next day, he was worse and went to the hospital. By the time he arrived, "his face and body had a bluish tint" ...never a good sign. When he was being examined, he was asked about the scar on his abdomen and he told the hospital staff it was from his spleen having been removed. They then asked about the bandage on his hand and he mentioned the dog bite. (Insert big ringing bells here!) The article says that the medical staff couldn't pinpoint the problem right away, but hopefully Capnocytophaga was a leading thought. Mr. Moore was critically ill by this point with multiple failing organs. He was admitted to ICU, became septic (overwhelming infection in his bloodstream) and was put on a ventilator. His hand had to be amputated, as did both legs below the knee and three fingers on the remaining hand. But he survived. (Despite the obvious long-term problems, he's very lucky to be alive after such a severe infection).
People that have had their spleens removed or who have non-functional spleens are at much greater risk for various infections, such as Capnocytophaga infections. No one should be allowed to leave a hospital after having their spleen removed without a letter saying, among other things, if you are bitten by a dog, get thee to a physician (pronto)! If you don't have a functioning spleen, make sure you know the risks and how to protect your health.
A lawsuit against various parties, including a dog, has been tossed out by a Michigan judge. Inez Starks sued the city of Warren, several police officers and Liberty, a police dog, after being bitten during some sort of confrontation in 2007. I don't have any details about the bite, but "unprovoked attack" and "police dog" don't tend to go together. Police dogs can and will bite in certain situations, but these are extremely well-trained and well-handled dogs. Most people that are bitten by a police dog probably have themselves to blame more than anyone else. Inadvertent bites could potentially result from being an innocent party in the middle of a confrontation, I guess, but there is no indication this person was merely an innocent bystander.
Anyway, the suit was tossed out by the judge. As a good example of sanity in the legal system, the judge fined Starks' lawyer for naming the dog in the suit.
Dog bites are a big deal and the cause of many lawsuits. Dog owners need to take their responsibilities seriously to reduce the risk of bites (and consequently being sued). At the same time, people need to take responsibility for themselves to reduce the likelihood of being bitten when confronted by a dog. Usually, that's focused on "be a tree" training in kids, but not upsetting police dogs is probably another good rule of thumb.
Recently, a relative was bitten by a dog, and the incident emphasized that you need to take such things seriously and pay attention to making sure things get taken care of properly.
So what should you do if you've been bitten?
1) Identify the dog.
- You need to know who the dog is, and who owns it. If you can't identify the dog, you have to assume it's rabid (even though it's extremely unlikely) and get treated with a series of vaccinations.
2) Get medical care as needed.
- Bites can be associated with significant trauma and risk of infection. Getting to a doctor is particularly important if the bite is severe, occurs at a high risk body site (e.g. over the hands, joints, tendons and nerves, groin, prosthetic devices) or if you are at higher risk of infection (e.g. immunocompromised, don't have a functional spleen, very young or very old, pregnant). If in doubt, go to a doctor to be on the safe side.
Once you've done this, it's important to make sure that the offending dog actually doesn't have rabies. If you go to a doctor, they will (in most regions) report the bite directly to public health. Public health inspectors will investigate the rabies vaccination status of the animal and ensure that it is quarantined for 10 days. If the dog has rabies and is infectious, it will develop signs of infection within this 10 day period. If the dog is healthy after 10 days, it did not have rabies at the time of the bite.
Seems pretty simple, eh?
Unfortunately, there are a few places where this process can break down.
Reporting: All bites need to be reported. Bites that do not result in people going to the hospital may be missed. You don't need a serious bite to contract rabies (or another serious infection).
Public health follow-up: This is hopefully not an issue, but you should make sure that public health has investigated, and done so promptly. Don't be afraid to call to find out the status of the investigation, and make sure information has flowed quickly from the physician to a public health inspector. Hopefully they'll be in touch with you, but don't be afraid to initiate contact. The main issue with follow-up relates to the next point:
Prompt euthanasia of the dog: Sometimes, people will decide to euthanize a dog after a bite, because it's done it before, because they consider any bite unacceptable, and/or they fear for family members or legal liability. Dogs (or cats) that have bitten someone must not be euthanized before the 10 day quarantine period is over. If the dog is euthanized and the body is not available for testing, you have to consider the dog rabid and undergo post-exposure treatment. Veterinarians are required to ask whether a dog has bitten someone in the preceding 10 days prior to performing euthanasia, but it's possible that this could be missed, or people may not tell the truth because they want to have the dog put down ASAP. This is why public health inspectors need to investigate promptly - to provide another level of assurance that the animal is not euthanized inappropriately. You should follow up with public health to make sure things are underway and the dog is quarantined.
Rabies associated with dog bites is extremely rare in Canada (and many other countries) but still kills tens of thousands of people every year, mainly in Asia and the Middle East. Considering it's almost invariably fatal and pretty much 100% preventable, you need to pay attention to the risks, no matter how small.
As a vet, I've been bitten by a wide range of animal species. When people talk about animal bites, they usually think about dogs and cats. Horses can (and do) bite as well. Most horse bites are probably playful nips that hurt a little yet don't cause major problems, but some bites can cause serious injuries and infections can result.
A recent paper in the Journal of Agromedicine (Langley and Morris 2009), with the rather unwieldy title of "That Horse Bit Me: Zoonotic Infections of Equines to Consider after Exposure Through the Bite or the Oral/Nasal Secretions". Bites apparently account for 3-4.5% of the approximately 100 000 annual emergency room visits in the US that are associated with horses. The authors of the paper review infections associated with bites and contact with organisms in the mouth and nose of horses.
A large number of bacteria have been associated with horse bite infections in people, including Actinobacillus, Streptococcus, Psuedomonas and Staphylococcus species. Some viruses can theoretically be transmitted by bites, but there's little evidence that this actually happens.
Although viruses are not of as much of a concern overall, rabies needs to be considered in every bite from a mammal. We pay a lot of attention to rabies with dogs, cats and wildlife, but it often gets ignored with horses. While I'm not aware of any reports of rabies transmission from horses to humans by a bite, it could happen. Fortunately, rabies is rare in horses so the likelihood of exposure from this species is very low. However signs of rabies aren't always obvious initially, and rabies in horses may mimic other diseases. Sometimes, rabies looks like colic, and human exposure through bites or other contact is possible when handling, evaluating and treating affected horses.
Unlike with dogs and cats, there are no clearly defined protocols for dealing with bites from horses. Any dog or cat that bites a person is supposed to be quarantined for 10 days. The reason for this is if the animal is rabid and the disease is advanced enough for the animal to be capable of spreading rabies virus, it would invariably develop signs of rabies and die within this time period. We don't have similar guidelines for horses. I suspect the 10 day observation period would be adequate but we don't have good data. The paper states that in Kentucky, a 14 day observation period has been used by the state Department of Public Health.
At the conclusion of the paper, the authors make a few important general recommendations for reducing the risk of disease transmission from bites and oral or nasal secretions of horses:
- Use good general hygiene, especially hand hygiene, after any contact with horses.
- Use gloves and gown or lab coat when examining horses in a veterinary clinic or hospital. (This might be overkill for all horses. We don't require gloves for every horse contact, just contact with mucous membranes (e.g. mouth, nose), wounds, incision sites and other high-risk areas. I think bare hands are fine for general contact as long as there is good attention to handwashing after.)
- Consider mask and goggles if the horse is coughing or sneezing.
- Develop standard operating procedures for handling sick horses.
- Use isolation when needed.
I'd add a few more points:
- Avoid bites. Pay attention to what you are doing around horses to reduce the risk of being bitten. Do not encourage playful behaviours (e.g. nipping) that could lead to bites.
- If you are bitten and it breaks the skin, clean the site thoroughly with soap and water. If there is significant trauma, or if the bite is over a joint, hand, foot, or a prosthetic device, you should see a doctor immediately because antibiotics are most likely indicated. If you have a weakened immune system, you should be evaluated by a doctor after any bite.
- Avoid contact with the horse's mouth or nose if you have skin lesions. Cuts and scrapes can allow bacteria to enter your body and cause infections. If you have a cut on your hand, make sure it is covered with a glove or waterproof dressing if you are going to have contact with the horse's mouth or something that came from its mouth (e.g. a bit).
This Worms & Germs blog entry was originally posted on equIDblog on 02-Sep-09.
Animal bites are very common. Millions of people are bitten every year, and the resulting burden in terms of pain, infection and financial costs is astounding. Dog bites get the most press because they often cause significant trauma. Dogs have larger and stronger mouths, and can bite repeatedly and more aggressively in some attacks. Deaths attributed directly to pet bites pretty much exclusively involve dogs.
Cat bites are smaller and have less chance of causing significant injury to tissues, but they may be more severe in the long run. There's a scientific paper called "Cat bite infections: biological warfare amongst cats," which is a testament to the nasty populations of bacteria that live in cats' mouths. It's not just the presence of bacteria that's a problem (afterall, dogs' mouths are full of potentially nasty bacteria as well) - the nature of cat teeth and the resulting bite wounds is a major factor. Cat bites often result in small but deep puncture wounds. This pushes bacteria deep into the tissues, where they're harder to get rid of and which results in a much greater chance of causing an infection. Furthermore, cats tend to bite areas that are high risk for development of bad infections, especially hands, which have a complex and susceptible network of tendons, tendon sheaths, joints and nerves. Bites that appear to be minor can end up causing serious problems, often much worse that an initially more dramatic dog bite.
Really, you don't want to be bitten by either a dog or a cat (or an iguana, hamster, person or anything else). A large percentage of bites are avoidable, and knowing how to interact with animals and read signals of aggression or fear are critical. If you are bitten, prompt and proper care of bites is required to prevent serious, long-term complications.
More information on bites, including management of bites, is available on the Worms & Germs Resources page. The CDC has a podcast that includes information about bite-avoidance that can be accessed by clicking here.
There's been a lot of talk (hype) in the press about pet bites and MRSA (methicillin-resistant Staphylococcus aureus). This relates to a paper in Lancet Infectious Diseases regarding infections associated with pet bites. Some press articles are more sensational than others, but most are taking the bite infection paper and building in unrelated comments about MRSA in animals to make it seem like there's a major MRSA dog bite epidemic underway.
I realize that MRSA is a hot topic that is easy for reporters to latch onto, but the problem is that the actual research related to MRSA is being taken out of context (and blown out of proportion). MRSA was certainly mentioned in the paper, but it was not the focus of the research nor do the authors play up concerns about pets as a source of MRSA infections. Nevertheless, the impression people are getting from many news articles is that there is rampant MRSA transmission by infected pets.
Is MRSA infection a potential concern after a dog bite?
- Yes, but more because of the bite itself than the particular dog. MRSA infections that occur after a dog bite are probably the result of contamination of the wound with MRSA from the person's own nose or from another person, for example during a visit to their physician/clinic/hospital. It's possible for MRSA to be in the mouth of the dog and for it to be transferred to the wound during the bite, but that's pretty unlikely. The person bitten or someone treating the wound is a more likely source of the bacterium. So, the bite was the ultimate "cause" of the MRSA infection, because the infection probably wouldn't have developed without that break to the body's normal defensive barriers (i.e. the skin), however the "source" of the infection was (in most cases) NOT the animal. The same kind of infection could have happened with any similar type of trauma.
What should I do if I'm worried about MRSA and dog bites?
- Worry more about dog bites than MRSA. Bites themselves are major problems, even if MRSA is not involved. The degree of trauma can be significant, and a variety of bacteria can cause serious bite infections, not just MRSA.
- Take measures to reduce the risk of being bitten, both in terms of how you handle and train your dog and how you interact with other dogs.
- If you are bitten, immediately clean the wound as thoroughly as possible. If the bite is over a joint, tendon (e.g. wrist/ankle), prosthesis or genitals, if there is significant trauma or if you have a weakened immune system, you need to see a physician. If you have any other concerns, get examined by a physician promptly.
More information on MRSA in animals can be found on the Worms & Germs Resources page.
Cab drivers have to put up with a lot of risks, but attacks from marauding rats probably aren't high on their list of concerns. However, a Ukrainian cab driver was recently attacked by a rat, and the rat was subsequently killed and found to be positive for rabies. The cab driver is now undergoing post-exposure treatment, and authorities are vaccinating pets and trying to eliminate mice and rats in the nearby neighbourhoods.
This is another good example of why it's important not to ignore a bite from any mammal, because rabies can affect any mammal. People often don't consider rodents a concern when it comes to rabies transmission, because most rodents would die from an attack by a rabid animal, thus preventing them from becoming infected and passing on the virus. This is probably true in most circumstances, but there have been enough reports of rabies in rodents, and potential human exposure from contact with rabid rodents, that we have to pay attention to this risk. Overall, the likelihood of acquiring rabies from a rat bite is pretty minuscule, and much less than the risk of contracting other diseases such as rat bite fever, but it's not zero. Since rabies is almost invariably fatal, even seemingly low risk situations need to be carefully assessed. In the case of this cab driver, there was definitely a risk of rabies exposure. If the rat had not been caught and tested, the potential for rabies exposure might have been dismissed, which could have had catastrophic consequences for the cabbie.
More information about rabies can be found on the Worms & Germs Resources page.
Rats can be really interesting pets. They can be quite social and are interesting to watch. Being larger than hamsters and gerbils, they can also be more easily and safely handled. They can still bite, however, particularly if they are not properly socialized and/or they are handled by people who don't know how to do it properly. Even though rats have tiny teeth, bites can still cause problems. One concern is rat bite fever. This disease is actually caused by two completely separate bacteria. Streptobacillus moniliformis is the most common cause in North America and Europe, while Spirillum minus is the main cause in Asia.
I'll focus on Streptobacillus moniliformis today. This bacterium is very commonly found in the mouths of healthy rats. Up to 100% of rats can be carriers. It doesn't cause disease in the rats, but it can be transmitted to people by bites or scratches. It can also be spread simply by handling rats (especially if a person has any cuts or broken skin), and through close contact with rats' mouth, such as kissing and sharing food (yes, some people do).
In most people, rat bite fever causes a high fever, headache, chills, vomiting, joint and muscle pain and a rash, most commonly over the soles of the feet, palms of the hands and the extremities. While the disease will resolve on its own in many cases, treatment with antibiotics is indicated because severe complications such as inflammation of the heart, pneumonia and meningitis can also develop.
Common sense can help reduce the risk of rat bite fever.
- Assume all rats are carrying S. moniliformis in their mouths.
- Only handle rats if you know how to do so properly, and if you know the rat is amenable to being handled. Avoid contact with the rat's mouth (e.g. kissing).
- If you have open sores or cuts on your hands, avoid handling rats or wear gloves.
- Always wash your hands thoroughly after handling a rat or cleaning its cage.
- Thoroughly clean any bites from any rodent immediately with lots of soap and water.
- If you develop signs consistent with rat bite fever after being bitten, consult your physician as soon as possible, and be sure to let your physician know about the bite.
Some areas of the world are fortunate enough to be rabies-free. However, there's a closely related virus that is of concern in many of these areas: European bat lyssavirus (EBLV). This virus is present in bats in various countries and can occasionally be transmitted to other animals. A recent report in the journal Emerging Infectious Diseases describes EBLV infection in two cats in France. Both cats died, although the actual cause of death of one of them was uncertain (the animal was also infected with feline immunodeficiency virus (FIV)).
Infection with EBLV in domestic animals is very rare. The risk to dogs and cats is probably very low, but obviously not zero. Avoiding contact with bats is always a good idea. Even in rabies-free areas, measures should be undertaken to keep bats out of houses, and people or animals should never touch sick or injured bats.
The risk to humans from infected domestic animals is unclear. It is thought that dogs and cats pose little risk for further transmission. While susceptible to infection, they are unlikely to transmit EBLV, probably because they produce very low levels of virus. Although there are no clear data about using standard rabies prophylaxis for the prevention of EBLV, it is believed that it would be effective if the virus was transmitted from an infected animal to a person. One cat in this report bit a veterinarian, who received a rabies vaccine booster since he/she had previously been vaccinated against rabies. Fifteen people who were exposed to the second cat underwent the recommended rabies post-exposure series of shots as a precaution.
Even in rabies-free areas, bites from bats or other wild animals should be taken seriously. They should immediately be cleaned thoroughly with lots of soap and water, and medical attention should be sought.
A big problem with EBLV is that it can be very difficult to diagnose. In this Emerging Infectious Disease report, several different tests were used and results were inconsistent. Multiple tests are probably needed to make a diagnosis. It's possible, therefore, that without this kind of comprehensive testing cases could be missed.
Overall, EBLV is a minor concern for public health, but is yet another reason to just use common sense - avoid contact with bats and treat bite wounds carefully, even in rabies-free areas.
I received the following question from a reader the other day: "I'm currently pregnant and was bitten by my grandmother's German Shepherd. The bite was on my ankle and broke the skin in several places. I went to the doctor and was prescribed antibiotics and the wound has seemed to heal fine. This is my second pregnancy and I have been diagnosed as group B strep positive, which I wasn't with my first child. I know that dogs can't spread strep throat to humans, but is it possible that I picked up group B strep from the bite?"
The short answer is that it's extremely unlikely there's an association.
Group B Streptococcus is predominantly a problem in people. Most people that carry this bacterium have no problems, although it can cause infections in some situations. It is of particular concern in pregnant women, because in 1-2% of exposed newborn babies the bacterium can cause serious infections such as bloodstream infections, meningitis and pneumonia. That is why pregnant women are often screened for Group B Streptococcus shortly before their due date, by taking a swab from the vagina and rectum. Approximately 10-30% of pregnant women carry Group B Streptococcus. Pregnant women that are carriers are usually given antibiotics shortly before delivery to reduce the risk of infection of the baby.
What about the role of pets? Group B Streptococcus is mainly found in people, and is quite common in healthy people. It is rare in pets, although it can cause various types of infections in animals too. Group B Streptococcus infections in dogs might actually represent human-to-dog transmission, although this hasn't been proven. In the case described above, a dog bite on a person's leg would not be a high risk for transmitting this bacterium to the intestinal tract or vagina. If a dog was carrying this bacterium in its mouth, it could cause a bite wound infection, but it is very unlikely that the bacterium would spread to other parts of the body in a healthy person. Other bacteria in the dog's mouth would be more likely to infect such a wound, even if Group B Streptococcus was present. If dogs were common carriers of this bacterium (which they are not), the main risk of transmission would be from regular contact, not bites.
So don't blame the dog... at least not for the Group B Streptococcus. The bite itself is another issue.
I did a presentation at a conference last week with a physician on the topic of "Pets and Immunocompromised Owners". It led to some interesting discussion. People with suboptimal immune systems are becoming more common in households and they often own pets. These individuals are susceptible to infections caused by microorganisms that would not typically cause disease in healthy people, and they are also more susceptible to severe (including fatal) disease caused by microorganisms that would only otherwise cause mild disease. Therefore, there's a lot of concern about pets transmitting infection to immunocompromised people. Rarely is removal of pets from households of immunocompromised people necessary, but precautions should be taken to reduce the risks of disease transmission.
One topic that comes up periodically is testing for Bartonella henselae. This bacterium is the cause of cat scratch disease, which is spread by cats through scratches (obviously) but also through bites and by fleas. Cats that carry Bartonella henselae hardly ever have any signs of disease. In healthy people, cat scratch disease typically causes fever, local lymph node swelling, headache and fatigue. Immunocompromised people, particularly people with HIV/AIDS, are at higher risk for severe disease, which can be fatal if it is not identified and treated promptly. Similar disease can also be caused by other species of Bartonella that are not carried by cats.
Tests for Bartonella are not 100% accurate. Some tests just indicate exposure which does not tell you whether the cat is still carrying Bartonella or if it was previously exposed but already eliminated the bacterium from its body. False negative tests (e.g. the cat has been exposed but the test comes back negative anyway) can also occur. When considering screening tests, or any diagnostic tests in general, only do a test if there's a reasonable chance that the results will affect what you do.
- If a cat is positive, I wouldn't recommend removing it from the house. It may or may not be shedding Bartonella, so the key points for avoiding cat scratch disease are reducing the risk of bites and scratches, and controlling fleas.
- If a cat is negative, it's probably (but not guaranteed to be) free of Bartonella, but it could be infected later in life, and the key points for avoiding cat scratch disease are reducing the risk of bites and scratches, and controlling fleas.
So, if the recommendations are exactly the same in both cases, save your money and spare the cat the blood sample. I don't recommend testing for Bartonella henselae. The Infectious Disease Society of America also does not recommend testing (or treating) cats for Bartonella in their guidelines for HIV/AIDS patients.
A recent article in Canadian Living talked about how to treat pet bites. Three main tips were provided. My comments follow in bold.
1) If the bite has punctured the skin, wash the wound thoroughly with hot water, then cover with a sterile bandage. Excellent advice. Immediate cleaning of the wound is very important.
2) If the wound/scratch appears to be swelling, soak the area in a warm bath of Epsom salts: If the wound appears to be swelling (a sign of potential infection) get thee to a physician. Actually, you should "get thee to a physician" before it gets to that point. A physician should be consulted promptly following any bite over the hand, over a joint or tendon sheath (such as on the wrist or ankle), over any kind of implant or prosthesis, or in the groin area, or any bite to person who has a weakened immune system, who has had their spleen removed, or who has any serious underlying chronic disease. A large percentage of bites occur over these high risk sites, particularly the hands.
3) If the wound continues to look inflamed, visit your doctor right away.You're better off getting this addressed proactively, before the site is swollen and persistently inflamed. It's much easier to prevent bite infections than treat them.
Another tip I'd add is make sure the animal's rabies vaccination status is known and report the bite to the appropriate Public Health authorities. There's a big difference in terms of consequences and what needs to be done if it's your pet versus some random animal you know nothing about.
The best information in this article was a very important point. "What is Dr. Conway's best advice when dealing with aggressive pets? Avoid a bite altogether by taking proper precautions." That's the key. Knowing how to interact with animals is a critical aspect of bite avoidance.
Bartonella henselae is a small, Gram-negative bacterium that is host-adapted to cats. It may rarely cause mild illness in cats, but most felines, from tiny house cats to the king of the beasts, carry the bacteria with no clinical signs whatsoever. Unfortunately, when B. henselae infects a person it can cause any of several serious conditions (most of which have very long names!). These include bacillary angiomatosis (formation of masses of abnormal blood and lymph vessels), endocarditis (infection of the lining of the heart), chronic lymphadomegally (enlarged lymph nodes), and pyogranulomatous lymphadenitis, better known as cat scratch disease. There are at least four Bartonella species (among many, many other Bartonella species) that can infect cats, but B. henselae is the most common. There are at least nine Bartonella species that can infect humans, seven of which are zoonotic.
Between 5% and 40% of cats in the USA have B. henselae in their bloodstream. It is most common in cats from temperate areas, and is much less common in Canada. Bartonella spp. live in the red blood cells of their host – quite a clever strategy really, because it makes the bacteria readily available to be picked up by vectors like blood-sucking fleas, it protects the bacteria from the hosts immune system so it can live there for a long time, and it may even partially protect the bacteria from antibiotics. Cats can maintain a waxing and waning infection for months or even years. The bacterium is transmitted between animals by the cat flea (Ctenocephalides felis felis). Studies have shown that transmission does not occur between cats kept in a flea-free environment. Some ticks may also be able to transmit the disease. Diagnosis in cats is difficult – blood culture is the most reliable means, but it is not always sensitive. Antibody production only confirms exposure but not active infection. Polymerase chain reaction is often faster but no more sensitive than blood culture. An effective treatment regimen to eliminate B. henselae infection in cats has yet to be determined.
Transmission of B. henselae from cats to humans is thought to occur through contamination of scratches and bites (broken skin) with flea dirt (i.e. partially digested blood from the infected animal that is excreted by fleas = flea poop). Infection in individuals with weakened immune systems can be extremely serious or even fatal. In otherwise healthy people, the infection tends to remain localized, but can still cause massive swelling and abscessation of local lymph nodes. The type of disease that occurs may depend on the strain of Bartonella involved.
There are a few simple steps people can take to decrease the risk of cat scratch disease. These are particularly important for individuals with compromised immune systems, in which infection can be much more severe:
- Keep your pets flea- and tick-free. Effective treatment and prevention products are available from your veterinarian.
- Avoid or prevent situations that may result in bites and scratches from your pet. There is more information about this on the Worms & Germs Resources page and in our archives. If you do accidentally get scratched or bitten, be sure to clean the wound thoroughly. Consider seeking medical attention for bites in particular.
- Be aware of where cats come from. Stray or shelter cats less than one year old are most likely to be infected with B. henselae.
It is also important to note that there is NO evidence that declawing cats decreases the risk of transmission of B. henselae to humans!
As a point of interest, Bartonella quintana (a human-adapted Bartonella species) was the cause of trench fever in World War I, and was transmitted by lice.
I admit I was a little slow picking up this Christmas story, but it's still "entertaining" (for lack of a better word). I've never thought about it, but I guess there are certain risks associated with playing Santa for pet photos. I'm not one to take my pets for pictures with Santa, but many worthy groups raise funds this way. During one recent event, "Santa" was bitten by a less-than-cooperative feline named Benny, who apparently didn't appreciate being in the company of the dogs which had also come. To make things worse, Benny wasn't your average cat - he was a pixie-bob, a very large breed of cat that resembles the North American bobcat (but it is in fact an entirely domestic breed)(pictured at right, from NBC10). After the incident, Benny's owners apparently produced proof of rabies vaccination, and everyone seemed fine. Besides the rabies concern, cat bites are not necessarily innocuous and severe complications can occur. That's one aspect of the story which hopefully didn't develop.
My point in writing this is to reiterate (again) my frequent statement that people need to make sure that their pets are properly vaccinated, even those that stay indoors all the time. Indoor cats can still bite people that visit, they can be exposed to rabid bats, and they can (not infrequently) escape. In this incident, if the cat had not had proof of rabies vaccination, a long quarantine period or even euthanasia may have been required - certainly not what anyone expects from a Santa photo-op.
And... maybe it's not a good idea to take large cats into strange places surrounded by dogs and thrust them into the arms of a strange person...something to consider.
Lots of people have heard of cat scratch fever (an infection caused by Bartonella henselae, which is often transmitted by cat scratches and bites), but dog bite septicemia is a much less familiar condition, although it is equally if not more serious when it occurs. As the name suggests, the infection (caused by the bacterium Capnocytophaga canimorsus) is typically transmitted by dog bites, and causes an infection of the bloodstream, resulting in very serious body-wide illness. The bacteria can also cause other types of infection including meningitis, endocarditis (infection of the heart valves) and rarely ocular infections.
One study reported that 16% of dogs carried C. canimorsus as part of the normal bacteria in their mouths. Compared to the number of dog bites that occur, C. canimorsus infection is relatively uncommon. Most of the people affected by this bacteria have some kind of predisposing factor, particularly having had their spleen removed (splenectomy), having a weakened immune system, or being an alcoholic. The majority of cases occur in people who have regular close contact with dogs or who were bitten by a dog. Septicemia with C. canimorsus is fatal in approximately 1/3 of cases.
Prompt attention and treatment of dog bites is the best defence against bite-associated infections, including C. canimorsus. The bacteria are typically susceptible to many different antibiotics, but if treatment is delayed too long, the damage to the body may be too severe for the patient to survive.
ALL bite wounds should be taken seriously, and immediately washed thoroughly with lots of soap and water. Consult a physician for any bite on the hand, over a joint or tendon sheath (such as on the wrist or ankle), over any kind of implant or prosthesis, or in the groin area. It is also very important to consult a physician regarding treatment of any bite to a person with a compromised immune system, who has had their spleen removed, or who has any serious underlying chronic disease. Animal bites should also be reported to the local public health department.
More information on bites, much of which is also applicable to dog bites, is available on the Worms & Germs Resources page on the cat bites information sheet.
Picture: Trained attack dog Samo leaps forward toward a decoy's arm wrap as Tech. Sgt. David Adcox restrains him. (USAF Photo archives)
I just received this comment from a reader of an earlier post about blastomycosis:
What should be done if a person was bit by a dog with blasto? I was trying to pill a dog who has blasto and the dog just out of reflex shut her mouth on my finger. What are the chances of the blasto being transmitted to me?
It's a reasonable question and one that I get periodically. If the bite didn't break the skin, the risk is essential nil. If the bite broke the skin, the risk is still fairly low, but certainly not zero.
Simple contact with an infected dog cannot result in transmission of blastomycosis because Blastomyces is a dimorphic fungus, meaning it can take the form of either a mold or a yeast. The highly infectious mold form is found in soil at ambient temperatures, while the minimally transmissible yeast form is present in the body of an infected animal or person. However, bites can be a different story. A bite from a dog with advanced pulmonary blastomycosis (e.g. fungal pneumonia due to Blastomyces) can result in localized blastomycosis at the site of the bite (e.g. only the person's finger might get infected).
Considering the dog in this case was already being treated for the infection (and therefore hopefully was not shedding much of the fungus), and that there are very few reports of bite-associated blastomycosis, the risk is probably quite low. However, any bite that breaks the skin can result in infection from the multitude of bacteria in an animal's mouth. Any bite on the hand should be taken seriously because it's easy for sensitive structures like joints and tendon sheaths to become infected. Consulting your physician or getting medical attention is recommended.
More details about general issues regarding animal bites are available in our bites archives. Relevant information is also available in the Cat Bites information sheet on the Worms & Germs Resources page.
Photo: Light micrograph of the budding yeast form of a fungus.
A study was recently published in the Veterinary Record (O'Sullivan et al, 2008, volume 163) describing 234 dog bites in people in Ireland. Dog owners and victims of dog bites were interviewed to characterize the incidents. Bites were divided into 2 categories: bites to the dogs' owner(s) and bites to someone who didn't own the dog. Here are some parts of the study that I found interesting:
- A large number of dog breeds were involved. The breeds most commonly involved in bites were also the most common breeds in the country, indicating that higher bite numbers for certain breeds were a reflection of the breed popularity, not a breed-associated propensity to bite.
- A large percentage of individuals that were bitten were adults, but children were more often involved when the bite was caused by a dog that was not owned by the family. The reason for this is unclear, but may relate to inadequate supervision of the interaction of children and "strange"/unfamiliar animals, or inadequate education of children about how to interact with such animals.
- Slightly over half of the bites from dogs not owned by the victim occurred off the dog's property, which demonstrates that exercising proper restraint of dogs (e.g. preventing roaming, maintining good control of dogs when walking, keeping dogs leashed when necessary) could potentially have a major impact on the number of bites.
- 27% of non-owners and 10% of owners suffered multiple bites or sustained attack from the dog involved. This is a serious concern, because multiple bites or attacks are presumably more likely to result in serious injury, and children are more often bitten by dogs not owned by their family.
- 13% of non-owners and 7% of owners were admitted to an emergency department as a result of the bite(s). Non-owners were more likely to be hospitalized and require major medical treatment.
- Bites to the hands were reported more frequently in the owner group. Bites to the hands may occur due to improper interaction with dogs, inadvertent bites when playing, or behavioural problems like dominance aggression, which can result in bites when a person tries to take away food or a toy from the dog. Proper training of pets - and owners - is critical.
- 70% of owners and 81% of non-owners described the bite as unprovoked. However, in 45% of bites to non-owners, the person was on or very near the dog's property, so territorial behaviour may have played a role. Also, some people who reported the bite as unprovoked simply may not have recognized (a) signal(s) from the dog that it was aggitated and may bite. Again, better education of people is very important, in combination with appropriate restraint and training of the animal.
- 24% of owners and 22% of non-owners were bitten on a Wednesday. I have no idea why. Do dogs get cranky in the middle of the work-week like some people???
More information on dog bites can be found under "bites" in the Worms & Germs Archive.
A recent report in the Medical Journal of Australia described the case of a woman who was pecked in the leg by her daughter's pet magpie. The woman was otherwise healthy (i.e. she did not have a compromised immune system), but the wound became infected by the fungus Saksenaea vasiformis, which rarely causes disease in people or animals. The infection became so severe that the woman's leg had to be amputated.
Saksenaea vasiformis can be found in soil all over the world. There are a few possible routes by which the fungus may have infected the woman's leg in this case. The fungus could have been on the person's skin, and been carried into the deeper tissues by the pecking. It also could have been on the bird's beak. Alternatively, it could have contaminated the wound after the pecking, through contact with soil or dirty hands.
This is an example of an infection that would be difficult to anticipate, since it occurred in a healthy person as a result of contact with a healthy bird, and with minor trauma, but potentially could have been avoided. Although the bird may not have been the source of the fungus, the break in the protective barrier of the skin was the critical event. Basic wound care is always important, and any injury from an animal should be taken seriously and properly addressed. Wounds should be carefully cleaned and monitored for signs of infection. A physician should be consulted as soon as possible if there are any concerns. A physician should always be consulted for any wound that is:
- on the hands
- over a joint
- over a tendon (e.g. wrist, ankle)
- in the genital area
- over a prosthetic device
- sustained by a person with a compromised immune system (e.g. HIV/AIDS, transplant or cancer patient)
More information on bites can be found in the Cat Bites information sheet on the Worms & Germs Resources page). It's unclear whether any of these precautions would have prevented the serious fungal infection that occured in this case, but these measures can reduce the risks of infection.
Many dog owners love to take their canine companions to the beach with them during the summer. Unfortunately, other people (particularly non-dog owners) sometimes take exception to having Bowser on the beach. These individuals often cite potential infectious disease risks as a reason to ban dogs from the beach.
While there are some potential infectious disease risks associated with having pet dogs at the beach, they are minimal. Also, some simple, common-sense steps can greatly reduce the risks that do exist. The infectious disease risks from feral (wild) dogs and wildlife defecating in the sand are much greater.
- The biggest health risk is actually probably from dog bites. Bites can be avoided through proper handling and training of dogs that are brought to public beaches.
- Many different bacteria (e.g. Salmonella, Campylobacter) can be passed in the stool of even healthy dogs. Some of these can be harmful to people, but only under certain circumstances, such as if they are swallowed or if they contaminate an open wound.
- Promptly picking up any stool passed by a dog greatly reduces the risk of significant contamination of the sand. Also, sunlight is an excellent “disinfectant” and will help kill any residual bacteria left behind.
- Dogs can also have different kinds of zoonotic parasites in their stool.
- Some of these parasites (e.g. roundworms, hookworms) are passed in a form that takes days to become infectious to people. So promptly removing dog stool from the beach minimizes the risk of transmission.
- Other parasites, such as Giardia, are immediately infectious when passed in the stool, but must be swallowed to cause infection. Prompt removal of dog stool, good hand hygiene with soap and water or an alcohol-based hand sanitizer before eating, and avoiding sand contamination of food and drink should largely eliminate this risk as well.
Overall, the risks of having dogs on beaches are very low if people behave responsibly, specifically properly restraining their dogs and promptly picking up stool.
More information about zoonotic diseases associated with contamination of sand and Sandboxes is available on the Worms & Germs Resources page.
General recommendations for introducing a baby to your pet are available, including "And Baby Makes Four" and "Preparing Your Pet For Baby's Arrival" from the Calgary Humane Society. The Calgary Humane Society offers a program call New Baby, Old Pet, which is designed to help families make the introduction of babies to pets safe and happy. If you are expecting a new arrival in your family, you should consider contacting your veterinarian, local humane society or public health unit to see if a similar program is available in your area.
This is just one more piece of evidence indicating the importance of dog bite prevention. The $356 million cost is just insurance claims. Not all bites are associated with insurance claims but can still be associated with financial costs, in addition to the obvious pain and emotional costs. There were ~14 500 insurance claims in 2007, but it is estimated that 4.7 million people are bitten by dogs in the US each year, with 800 000 people requiring medical care.
In the US, dog owners are liable for injuries caused by their pets in the following circumstances:
- if the owner knew the dog had a tendency to bite
- if a state statute makes the owner liable, whether or not the owner knew the dog had a tendency to bite
- if the injury was caused by carelessness on the part of the owner
It is important that everyone, pet owners and non-pet owners alike, know how to reduce the risk of being bitten by a dog. More information on bites can be found in the bites archives or in the dog information sheets in the Resources section.
You should see a doctor about any cat bite on a hand, over a joint, over a tendon sheath (such as the wrist or ankle), over a prosthesis or implant, in the genital area, or that causes a deep tear. You should also see a doctor for any bite if you happen to have a weakened immune system for any reason (e.g. HIV/AIDS, cancer or transplant patients).
The best way to prevent infection is to prevent the cat from biting you in the first place!
- Use common sense – know how to handle a cat properly so that it is not frightened or uncomfortable. If a cat growls at you or tries to get away, let it go!
- Don’t let cats play with your hands, feet or hair. Use a nice cat toy instead.
- Don’t approach strange cats, especially strays. If you are bitten by a cat that may not have been vaccinated for rabies, it is very important to report the incident to you local public health department and your doctor, as you may need to receive rabies post-exposure prophylaxis (PEP).
Some key points to teach children:
- Never approach a strange dog
- Be careful and quite when approaching a dog - never make sudden movements or loud noises
- Do not play with a dog without adult permission and supervision
- Never disturb a dog that is eating, sleeping or taking care of puppies
- Never take something out of the mouth of a dog
- Avoid direct eye contact with strange or aggressive dogs
- "Be a tree": If confronted by a strange or aggressive dog, remain still and quiet
- If knocked over by a dog, curl into a ball and remain still
- Tell any adult about any bite. Try to remember as many details as possible about a dog that bites so that the owner can be found and the rabies vaccination status of the dog verified
My dog licked someone with HIV/AIDS, and they had an open sore. Can my dog get HIV?
Can a dog that bites someone with HIV get infected?
If a dog bites someone with HIV then bites someone else right after, can it spread the virus?
The answers are no, no and it's very, very unlikely.
HIV (human immunodeficiency virus) does not infect dogs. Regardless of how a dog is exposed, it will not develop an infection. HIV is also a very fragile virus. It does not survive long in the environment and a dog's mouth is not a very hospitable location. It is theoretically possible that if a dog bit someone with HIV and then immediately bit someone else, it could transfer the virus, but this has not ever been identified and is very unlikely. In some countries, the source of all cases of HIV are investigated, and an animal bite has never been implicated as a potential cause.
Bottom line....don't worry about HIV and your pets.
First of all, think about where that mouth has been, and what’s been in it! Does your cat hunt mice and birds around your house? Does your dog have a habit of eating unidentifiable bits of garbage or poop when out on walks? Or maybe your dog, like so many, enjoys a snack from the cat’s litter box every once in a while. You probably want to keep things like garbage and poop out of your cuts, and if your pet’s mouth has been there, it shouldn’t be near your wounds either.
Even dogs and cats that don’t have any distasteful eating habits have millions of bacteria of many different kinds in their mouths. Most of the time the bacteria don’t cause a problem, and the “good” bacteria help to keep the “bad” bacteria in check. But if the “bad” bacteria are put somewhere the body’s defense systems have already been breached – like an area of broken skin – those same bacteria suddenly have a prime opportunity to move in and start multiplying in their new home. Some bacteria like Pasteurella multocida can cause very serious infections in situations like this. This species of bacteria is one of the primary culprits in bite wound infections, which are especially common with cat bites.
So why do animals lick their wounds in nature? Well, “dirty” is in fact a relative term. An animal can use its tongue to get the worst of the dirt and debris out of a wound, and the wound will be cleaner. But compared to how clean you can make a cut by even just washing it with a lot of water and some soap, and maybe a little disinfectant, a lick from a cat or a dog is counterproductive to say the least. So the next time you have a boo-boo that Fifi or Fido wants to kiss better, say thanks, but no thanks.
INFORMATION SHEETS specifically for KIDS, for VETERINARIANS, for PHYSICIANS and for PUBLIC HEALTH PERSONNEL are also available on the Worms & Germs RESOURCES page!
Click on the highlighted topics below for information sheets. Topics that are not highlighted are in development and coming soon. Sheets for other animal species and diseases are also under development and will be added when they are available.
- Your veterinarian and physician are your ultimate resource for information about the health of your pets or your family.
- Information provided here is accurate to the best of our knowledge, but infectious diseases can be unpredictable and these sheets are for general information purposes only.
- There can be great variation in disease risks in different geographic areas. The information provided was developed for Ontario, Canada, but most of the information is relevant for other regions as well.