Dogs and Giardia types
While the potential health risks to people exposed to dogs with Giardia have received a lot of attention (and concern), there's more and more evidence indicating that dogs pose a very limited risk to people. Giardia is a protozoal parasite that can cause diarrhea in numerous animal species, including people and dogs. It can also be found in healthy individuals, with several reports describing evidence of Giardia in the feces of approximately 7% of healthy dogs.
In the recent past, as easier-to-perform tests for Giardia became available, people sometimes tested healthy animals for the parasite, and then had to figure out what to do with positive but healthy pets. It has not been unusual for such dogs to be treated because of concerns about the potential for infecting people. However, it's becoming increasing clear that this risk is minimal.
The reason the risk is so low is due to the fact that not all Giardia are created alike. There are different assemblages (types) of Giardia, and not all types can infect all species. Knowing the types found in dogs and the types that cause illness in people can tell a lot about the potential human health risk. One more recent study has indicated that risk of animal-to-human transmission is likely very small.
In that study (Itoh et al, Veterinary Parasitology 2010), researchers tested fecal samples from 1794 puppies in pet stores in Japan. Giardia was detected in 23% of puppies. This is a pretty high number but it's not really surprising, as this highly mixed population of young, stressed animals would be considered high-risk compared to the average pet dog. All Giardia were assemblages C or D, which are dog-specific. Therefore, despite 23% of the puppies shedding Giardia, none posed a risk for human infection.
Yes, Giardia is a zoonotic infection, but the risk of dogs infecting people appears to be very low because dogs so rarely carry the types able to infect people. Beyond that, this is a "don't eat poop" disease, whereby the use of good hygiene practices to prevent inadvertent ingestion of Giardia from dog feces can reduce the risks even further.
Attack of the (maybe) rabid otter
A teenager who was filming an otter he spied in a pond now knows more about rabies than he probably ever wanted. The 19-year-old shot the video from the bank of a pond, watching the otter innocently swimming around. After a brief stare-down, the otter did another quick swim, then ran onto shore and attacked! And it was all caught on camera and displayed to the world via YouTube.
This is the third recently-reported otter attack in the area. This type of behaviour obviously isn't normal, and rabies has to be a concern. Rabies has been previously identified in marauding otters in Florida, and since this otter got away, you have to assume that it was rabid. Accordingly, the victim is undergoing rabies post-exposure treatment.
Swedish antimicrobial guidelines
The Swedish Veterinary Association has released an English version of their 2009 "Guidelines for the clinical use of antibiotics in the treatment of dogs and cats". It's a very comprehensive document that goes through various medical conditions and discusses antibiotic use recommendations. As concerns about antibiotic use and misuse increase, more organizations are putting the significant effort that is required into developing such guidelines, and they can be a tremendous asset. While there are still significant limitations in the available research needed to produce evidence-based guidelines, a combination of careful review of existing information and expert opinion can provide good guidance for treatment of infections in companion animals.
There are always a few disclaimers that need to be given when presenting antibiotic use guidelines:
- They are guidelines, not standards. They provide a general overview of the issues and how to manage most patients, but some patients don't read the book and need to be treated differently.
- Disease and drug resistance patterns vary between regions. These patterns need to be considered, particularly when considering guidelines produced in another area or country.
- Things change over time. As guidelines age, some parts of them may become less relevant.
- There are differences in antibiotic access and licensing between regions.
Regardless, sound guidelines like these are needed and will hopefully help improve both patient care and control of the scourge of antibiotic resistance.
Researchers uncover medical mysteries of the 100 acre wood
Pardon my straying from the zoonotic disease realm, but here's a little light reading... (for the pdf version with images click here).
Medical Mysteries of the 100-Acre Wood
Children around the world have been entertained by activities in the 100-acre-wood for decades. But at what cost to the animals? What kind of example is this setting given the obvious medical and ethical problems present in these animals? As protectors of animal health and welfare, and fully cognizant of the ethical requirements put upon us by the Veterinarian’s Oath, we feel bound to address these issues and call for immediate action.
Winnie the Pooh may be a lovable creature, but he clearly has numerous health problems. Despite being born in 1926, Winnie the Pooh appears not to have grown to adult height. This stunted size may be the result of a primary growth hormone deficiency, but we suspect that it is solely the result of inadequate nutrition. His body mass index is excessive, in large part from his inadequate diet. A diet based solely on honey is inadequate for a growing bear. The caloric density is a main factor in this animal’s obesity. As well, it is virtually guaranteed that Pooh has, or will soon have, numerous nutritional deficiencies based on this diet. Pooh also seems rather "slow on the uptake" which may be the result of inadequate omega-3 fatty acid intake. Unlike many other bears feasting on wild salmon and other sources of these important fatty acids, Pooh’s omega-3-deficient diet has not provided him with the neuroprotective and developmental benefits that omega-3s provide. Sadly, this is irreversible and Pooh will never be able to obtain his true genetic capacity for intelligence. Despite the irreversible nature of his improper brain development, there are other areas that can be improved and his diet must be addressed immediately. This may not be easy, given decades of inadequate diet and conditioning to only eat honey. While some may recommend the use of mirtazapine to stimulate his appetite along with provision of a normal diet, we disagree and believe that a more natural approach involving complete restriction of honey along with providing an adequate diet will be successful. Use of mirtazapine may be unnecessary, particularly once hunger sets in. Further, this would be an off-label use of the drug and we have little confidence in available ursine dosing data. There is always concern regarding the metabolic efforts of dietary restriction in overweight animals, but we are unable to find any published reports of fatty liver syndrome in obese bears being weaned from a honey-only diet, so this absence of published evidence clearly indicates that this is a completely safe approach. We do, however, recommend a complete hepatic evaluation prior to feed restriction because of the marked yellow pigmentation of this bear.
Eeyore clearly has a significant undiagnosed metabolic disease, given his body condition, poor muscle mass and lethargy. While equine metabolic syndrome has been poorly investigated in donkeys, it is a likely explanation for the excessive body condition. The slow purposeful movements exhibited by this animal also suggest the presence of a primary muscular disorder such as polysaccharide storage myopathy. At a minimum, muscle biopsy is indicated to determine the cause of his unwillingness to move beyond a crawl. Certainly, the slow movement and vocalization could be the result of a brain lesion but, sadly, Eeyore’s girth is too excessive for him to fit into existing MRI or CT scanners. Only with proper control of his metabolic disease and a good nutritional program will there be any ability to diagnose any cerebral component. Blind brain biopsy is not recommended due to the invasive nature of this diagnostic test and the rather low likelihood of actually identifying brain tissue in a donkey.
At the opposite end of the spectrum is Tigger, the hyperactive tiger whose incessant jumping and twitching likely indicates the presence of a cerebellar disorder. In the absence of advanced imaging (which would obviously require travel beyond the 100-acre-wood) one must make a presumptive diagnosis of cerebellar hypoplasia from fetal infection with feline panleukopenia virus. Unfortunately, there are no therapeutic options and there is a grave prognosis for clinical improvement. He must also have an additional neurological abnormality affecting his cerebral cortex since he has repeatedly shown an unwillingness to recognize readily available food sources, most notably a young pig.
Roo is an active young kangaroo. While his excitable, bouncy nature may simply be the exuberance of youth, we are concerned about the sustained energy. This concern is heightened by the fact that all images of this animal show profound papillary dilation to the point that his eyes appear completely black. This sign clearly indicates the potential for illicit drug exposure. Drug testing is required. His mother, Kanga, appears to be a loving, caring mother, with no apparent health problems. Despite this, she must be investigated as a potential source of Roo’s drug exposure because her attitude seems too persistently cheerful for someone spending all her time around a hyperactive youngster.
Piglet’s most obvious abnormality involves vocalization. There are many potential causes of vocalization abnormalities in pigs, including behavioural and neurological etiologies. Piglet appears to be the only piglet left from his litter, so congenital or neonatal infection that killed his siblings and left him with a serious stutter must be considered. We are hesitant to speculate about specific causes or the potential food safety risk. CT or MRI would be required to explore this further, but it is questionable whether this is justifiable given the cost involved for a pig. Further, consumer concerns about irradiated meat may preclude CT scanning.
Rabbit, while exhibiting classical signs of dominance, does not manifest his behaviour in bites or other serious outcomes. His dominating personality is more directed at controlling the daily activities of his cohorts, without obvious negative impacts. That, combined with limited pharmacokinetic or safety data for drugs like fluoxetine (Prozac) in rabbits lead us to recommend no treatment for this disorder. However, given the high prevalence of Encephalitozoon cuniculi shedding by rabbits, we must assume that he is carrying this animal and human pathogen in his kidneys, and ensure that contamination of the environment with urine is avoided. Concerningly, there consistently appears to be a dearth of hand hygiene opportunities in the 100-acre-wood, with few sinks and complete absence of hand sanitizers. This infection control deficiency must be addressed to contain the multitude of pathogens that appear to be present in this toxic environment.
And finally, on to Christopher Robin. While a minor, Mr. Robin is clearly the caretaker of this ragtag group of animals and certainly bears (pun intended) responsibility for their health and welfare. His obvious failure to provide adequate veterinary care is of significant concern and should result in immediate investigation. The potential for Christopher Robin to be the source, intentional or otherwise, of Roo’s illicit drug exposure raises numerous additional concerns. At a minimum, thorough veterinary examination of all animals and review of animal management practices should be mandated by regional authorities to ensure the health and welfare of these animals, as well as children around the world that are learning from Christopher Robin’s example.
Kennel cough clusters
I had a call from a colleague in Ottawa (Ontario) the other day, asking if I'd seen an increase in kennel cough in dogs lately. Kennel cough is a respiratory infection of dogs that can be caused by a variety of different viruses and bacteria, or combinations thereof, but is often associated with the bacterium Bordetella bronchiseptica. Apparently, this colleague's clinic has seen a large number of cases compared to normal, and he was wondering if the trend was more widespread and/or if there's something new out there to be concerned about.
Informal reports like this are often the key to identifying new problems. There are only a few reportable diseases of companion animals (such as rabies), and existing federal and provincial public health and animal health agencies tend to have little mandate regarding non-reportable infectious diseases of companion animals. That means that there is no centralized reporting or investigation for all these other diseases (in other words: we're on our own).
Most often, reports of higher disease rates or suspected outbreaks don't end up leading to anything. Things tend to revert back to baseline fairly quickly without any explanation of what happened. Sometimes, however, reports like this are the first in a series that can flag the emergence of a new disease or a change in existing disease patterns.
Is anything actually going on with kennel cough in Ottawa? It's hard to say. A report like this could be due to:
- A focal outbreak caused by exposure at a single kennel, park or event.
- A local outbreak of "run-of-the-mill" kennel cough that is being spread from multiple sources, but which involves the normal kennel cough bacteria and viruses.
- Increased reporting of the normal baseline rate of disease, with increased awareness leading to the appearance of an outbreak.
- A new disease (either a brand new disease or, more likely, the first instance of an existing disease in the area).
Whenever I hear reports like this in Ontario, I think about canine influenza. This virus is present in dogs in many regions of North America, but we have yet to identify it in Ontario (at least from the last data I have. We also couldn't find any evidence of canine influenza virus in a surveillance study we did a while ago). It is certainly possible that this virus could make it to Ontario, and I would not be surprised at all if canine flu caused a readily detectable cluster of respiratory disease cases when it arrived.
Should dog owners in Ottawa be worried? No.
Should dog owners and veterinarians in Ottawa pay attention? Sure. It's always good to be aware of things that are happening locally. Dog owners need to be aware of the risk of exposure to a variety of infectious diseases. Veterinarians should consider testing for canine influenza (and dog owners need to be willing to pay for the testing) if they see changes in respiratory disease patterns in their area.
How can dog owners reduce the risk of exposure of their dogs to respiratory diseases? Common sense. The more dogs that a dog meets, the closer they get to them and the less vaccination in the population, the greater the risk. Kenneling and other situations where many dogs get together increase the risk, and preemptive kennel cough vaccination should be considered in such cases. This vaccine doesn't protect against all causes of respiratory infection, but it can protect against some of the most likely causes. People should keep their dogs away from other dogs that look sick (especially dogs that are coughing), and if they have a sick dog, they should keep their dog away from other dogs for a few weeks.
Urban chicken debate
The debate about urban (backyard) chickens is again in the news, this time in Windsor, Ontario. The debate was ignited by a recent case in which a Windsor couple has been given one week to get rid of their backyard hens. The couple is preparing to fight the order, stating that the chickens are their pets, and no different than other pet species.
Different cities have taken different approaches to the urban chicken movement. Some allow or even actively support keeping urban chickens. Others ban them outright.
Supporters of the urban chicken movement say that the birds provide local, natural food and that they can be good pets. They say that a few chickens are no more noisy or disruptive than many dogs.
Opponents worry about the mess the birds make, odours, noise, attracting other urban wildlife like raccoons and skunks, and infectious disease risks.
Which position is right? I don't know. Bringing animals into closer proximity to people always increases infectious disease risks, but does it increase them enough to be a concern, and do the positive aspects outweigh the concerns? Even healthy backyard chickens can carry a variety of potentially harmful bacteria that could be spread by direct contact, or contact with the chicken's environment or run-off into neighbouring yards. However, the biggest problem is probably not these small groups of chickens spreading infection - the nuisance factor and attracting other animals (including rabies vectors) into the area might pose the greatest risk. We don't have enough information to make a very informed decision one way or the other. However, if people are going to keep backyard chickens and authorities are going to allow it, some common sense needs to be used in terms of how many birds are kept, how they are raised, how to dispose of manure, how to keep wildlife away, and general hygiene practices.
One more thing to be wary of is statements about food safety regarding urban chicken eggs. People sometime equate organic, backyard, non-intensively farmed animals as being no risk for foodborne pathogens. That's not the case. This type of farming does not necessarily result in safer food, and misconceptions to that effect can increase disease risks if people fail to take adequate precautions. Backyard eggs and poultry products need to be treated the same as products coming from a commercial farm.
What is a probiotic?
Probiotics are widely available and increasingly popular as "alternative" or "natural" approaches to treatment and prevention of disease. When considering the use of probiotics, it's important to think about what a probiotic really is. A widely used (and my favourite) definition is:
Probiotics are live microorganisms that, when given in adequate doses, provide health effects beyond that of their inherent nutritional value.
It's a great definition and has some key points to consider:
- Live microorganisms must be present. That's not always the case with commercial products.
- An adequate dose must be present. Some commercial products have very low levels of viable microorganisms. We have limited information about the required doses, and these would vary between bacterial species and animals species, but the low levels present in some veterinary probiotics are a major limitation.
- There must be a health effect. This is the key. If it doesn't do something beneficial, then it's not a probiotic.
Which brings me to my "head shaking product of the day": probiotic floor cleaner. Yes, floor cleaner. And it has a nice warm-and-fuzzy name: Peace of Mind Floor Cleaner.
According to the manufacturer, it reduces the risk of infection (infection of what, by what and how, are completely unclear). It also allegedly "keeps protecting surfaces for up to 3 days by leaving a long-lasting layer of beneficial probiotics that create a safe, stable and odor free environment. Don't let your floors make you crazy."
I didn't realize that floors were the cause of such angst and that covering them with probiotics can improve your life (hopefully the sarcasm is apparent).
What does this have to do with probiotics for treatment or prevention of disease in animals? Not a lot. But it shows how easily people can throw around the word "probiotic" as a marketing tool. Floor cleaners can't be probiotics since they aren't ingested and don't have health effects. However, the same type of scrutiny needs to be applied to any probiotic that you are considering using.
- Demand evidence of a health effect (real evidence, not just testimonials).
- Demand information about the recommended dosing.
- Find out what specific bacteria are being used.
- Don't stop thinking once you read "probiotic." On the contrary, when you read "probiotic" you should start thinking and asking questions.
Salmonella and iguanas: a rebuttal
Here's a comment from a well-meaning but ultimately misinformed reader. I'm commenting on it because these misconceptions are not uncommon.
"This blog post appears to be based on inadequate knowledge of iguanas. I am an iguana keeper and have been for several years. Unlike many reptiles, iguanas do not carry salmonella on their skin and are not a high salmonella risk. Furthermore, as long as the bath tub is disinfected afterward, there is generally no problem with iguanas bathing or even defecating in bath tubs shared with humans (although I do understand concerns of those with babies or immunocompromised people)."
Iguanas can and do carry Salmonella on their skin. It mainly resides in their intestinal tract but can easily contaminate their skin. For example, a 10-week study of 12 green iguanas reported that they all shed Salmonella at least once during the course of the study (Burnham et al, J Am Vet Med Assoc 1998). You have to assume that every iguana is carrying Salmonella.
People can and do get Salmonella from iguanas. There are numerous reports of salmonellosis from pet iguanas, including fatal infections. In a study of salmonellosis in people associated with exotic pets, iguanas were the most common source, accounting for over 50% of infections (Woodward et al, J Clin Microbiol 1997) Babies and immunocompromised people are at greatest risk, but infections occur in people outside of these high-risk groups as well.
Disinfection is far from foolproof. Yes, disinfection will kill Salmonella IF (and that's a big if) it's done properly. That includes properly disinfecting all tub surfaces, along with any other areas that were potentially contaminated (e.g. by splashes). This is far from guaranteed to happen in most cases, since people rarely understand what is required for proper disinfection and how to do it.
I'm not saying people should never have iguanas. Some people shouldn't: households with children under five years of age, elderly individuals, pregnant women or immunocompromised individuals. In other households, the risk is lower, but it's still there. An important part of managing the risk is knowing that the risk does exist. Pretending there is no risk doesn't do anyone any good.
Infectious disease considerations for fostering pets
Humane societies and shelters are often overwhelmed by the number of animals that come in. It's pretty uncommon to see much (if any) empty space in most shelters, and overcapacity shelters lead to increased risk of disease transmission, outbreaks and suboptimal care of the animals that are there.
One way of helping deal with overcrowding is fostering animals to people's homes for periods of time. Typically, foster homes take animals when shelters are at capacity, or take specific animals such as nursing cats, which are more difficult to care for properly in a shelter.
Most places have protocols for fostering, but they're not always very comprehensive and they don't always adequately cover some important areas. If you are thinking about fostering shelter animals, you need to think about the risks and whether you can manage them.
Are there people in the household that are at increased risk of infection?
Fostered animals should be assumed to be at higher risk of carrying and transmitting various infectious diseases. They can have high rates of carriage of various intestinal bacteria and parasites, along with a host of other microorganisms (e.g. ringworm). They may also be more likely to bite and scratch, not necessarily because they are aggressive, but often because they are young animals that may do so when playing. They may also be more likely to poop in the house.
Households with children under the age of 5, elderly individuals, pregnant women or people whose immune systems are compromised are at increased risk of various infections, both in terms of the likelihood of becoming infected and the likelihood of developing more severe disease. Households with these types of individuals should not foster animals. They are much better off having their own lower-risk pets.
Are there any "resident" pets in the household?
You might expect that someone willing to foster animals would also have their own pets, but that's not always the case. Non-pet owners are actually ideal, since this negates any risk of diseases being spread from or to household pets that live there long-term. However, it's more typical that foster homes also have such resident pets.
Are there any pets in the household that are at higher risk for infection?
As with people, there are some animals that are at increased risk of infection. These include the very young, very old, pregnant and pets with compromised immune systems. The latter group would include pets with chronic illnesses, those being treated with high doses of steroids for various diseases, animals with cancer, animals with diabetes, and a range of other issues. People owning a pet that fits into one of these categories should not foster animals because of the risk to their own pet.
How do you reduce the risks associated with fostering animals?
- May sure there are no high risk people or pets in the household.
- Make sure the shelter or organization knows what they are doing. Make sure they have a clear protocol that says who will be fostered and how it's done.
- Look at the animal before you get it. Visit it at the shelter. See if it looks healthy. If you have any questions, make sure it's examined by a vet before it reaches your home.
- Use good hygiene. Wash your hands regularly. Properly clean up feces and clean litterboxes regularly.
If you have pets of your own:
- Make sure they are vaccinated and on an appropriate parasite control program.
- Keep the new animal away from your pet at the start. That lets you find out more about the animal, and it gives you more time to see if there are potential infectious disease concerns.
- Do a controlled introduction of the new animal. Slow, supervised introduction of the animals can reduce the risk of bites or scratches.
Fostering is a good way to reduce pressures on humane societies and shelters, and to provide better care for some animals, like pregnant animals or those with young kittens/puppies. A good fostering program can be set up with limited risk to all involved, but infectious disease risks can never be completely eliminated. By accepting a new animal into your house, you increase the risk of exposing yourself and anyone else (human or animal) to infectious diseases. That's just a fact of life.
Pet food (beef) recall: Canada
The Canadian Food Inspection Agency (CFIA) and the Public Health Agency of Canada (PHAC) have issued warnings about frozen beef pet food made by Surrey Meat Packers of Cloverdale, BC. The Beef Pet Food consisted of frozen 500 g blocks of beef (presumably raw) sold between October 8 and 23, that may contain E. coli O157.
This is a bigger concern that the periodic Salmonella recalls that have affected both raw and cooked pet foods. Salmonella is an important cause of disease, but E. coli O157 is a particularly nasty bug. This bacterium can cause very serious disease in people, including hemolytic-uremic syndrome (HUS), a life-threatening problem that can lead to kidney failure. The infectious dose is very low - all it takes is ingestion of a small number of bacteria for disease to develop. Risks to people from this recall mainly involve the potential for cross-contamination with human food or inadvertent ingestion of E. coli O157 from pet food via contaminated hands. Transmission of E. coli O157 from dogs to humans has been reported, but is probably quite rare.
The health impact of E. coli O157 in dogs is less clear. Experimental infection of dogs with the bacterium has resulted in disease, but studies of naturally occurring diarrhea have not provided convincing evidence that it is a significant cause of illness in dogs.
No illnesses have been reported in association with this batch of contaminated meat. Given that the contaminated meat was sold until October 23 (a few weeks ago), it's likely that most of the meat has already been consumed at this point. However, people who have purchased this product and still have some sitting in the freezer should check it. Affected product may not have a label indicating a packing or best before date, in which case you should assume it's contaminated (better safe than sorry). Any meat from that period (or of unknown history) should be discarded.
This is yet another important reminder of the fact that raw meat products can easily be contaminated with various pathogenic bacteria. People who choose to feed raw meat to their pets must ensure that they take careful precautions to reduce the risk of human infection from cross-contamination or contact with pet feces. More information about raw meat feeding can be found on the Worms & Germs Resources page.
MRSP in the park
As multidrug-resistant bacteria such as methicillin-resistant Staphylococcus pseudintermedius (MRSP) become more common in pets, there are increasing questions about how to manage animals that carry them. A particular issue is what to do with carriers - animals that don't have any sign of disease but still carry the bacterium.
A small but increasing percentage of healthy dogs and cats are currently carrying MRSP in their nose or intestinal tract. The rates appear to be shooting up in most areas, and I suspect that the current carriage rate in a lot of regions is above 5%. In some groups of animals, particularly those that have received repeated courses of antibiotics, rates are likely much higher.
Back to the initial question... what to do with MRSP carriers?
Well, in some ways, we want to limit their contact with other animals to reduce the spread of the bacterium. However, we also have to realize that this is now a rather common bacterium, and it doesn't cause infections in the majority of animals that get exposed, and it is very rarely a problem in people. That doesn't mean we should ignore it, but it's a lot easier to justify being very strict with a bug that:
- is readily transmitted to people and can cause disease in people.
- is rare in the dog population.
- is highly infectious.
- usually causes disease when an animal is exposed.
These aren't the case with MRSP. It's still certainly a serious concern, but where do we draw the line between being proactive and being impractical?
Back to the title of the post... what to do with MRSP-positive dogs that go to dog parks?
It's a good question, and I don't have an answer in which I'm 100% confident. The paranoid infectious diseases part of my brain wants to keep MRSP carriers away from other dogs to reduce transmission. But, the practical part of me recognizes that parks are probably a limited source of transmission overall, that there are probably greater risk factors for the increase in MRSP, that we have no idea whether short-term contact such as meeting in passing at a dog park can result in efficient transmission, and that going to the park is an important activity for many people and their dogs.
Anyone that takes their dog to a dog park needs to understand they are increasing the risk of infectious disease transmission to (and from) their dog. This includes a wide range of bacterial, viral, parasitic and fungal diseases, not just MRSP. In fact, I think there are other pathogens that are a bigger concern from dog park exposure.
Should MRSP dogs be keep away from dog parks?
- When they have an active infection and are presumably shedding larger numbers of bacteria: Yes.
- When they are just carriers: Probably not.
How can I say that when I keeping talk about how big a deal MRSP is?
- It's a big deal, but it's mainly a big deal in specific circumstances, such as in dogs undergoing surgery, dogs with underlying skin disease and dogs that are exposed to antibiotics. There is no such thing as a no-risk dog, but the individual risk for a healthy dog is probably very low.
- You have to live. You can do the Howard Hughes model of infection control and barricade yourself in your room, or you can live life. Yes, that increases risk. But, we do things to contain that risk as much as possible, such as keeping sick dogs away from parks (to prevent both transmitting and picking up microorganisms), reducing antibiotic use and using good general hygiene practices.
- You don't want to purposefully infect other dogs, but the small number of known MRSP carriers is dwarfed by the thousands of dogs that are unknown carriers.
- In some respects, MRSA is the human version of MRSP, and it's a huge health problem. However, MRSA carriers are not locked away. We realize they are transmission sources but we focus efforts on carriers only in high risk situations, such as hospitals. Could we greatly decrease MRSA carriage in people by aggressively testing, treating and quarantining? Sure. Is it worth it? That's pretty questionable.
I never want to give the impression that we are being lax with an important infectious disease, but I just don't have the evidence (or anecdotes) that restricting park access for carriers will do anything for MRSP control, especially since known MRSP carriers probably represent 0.0001% of all MRSP carriers.
What can you do to reduce the risk of transmitting or acquiring MRSP at the park?
- Pick up feces. Dogs can shed MRSP in feces, and this could be the most important route of transmission given how some dogs like to nose and eat feces (my dog being the poster child for that particular habit).
- Watch your dog closely so it doesn't eat feces (or at least is less likely to).
- Don't let your dog have contact with an animal with any signs of an infection, particularly a skin infection.
- Try to limit nose-nose, nose-bum contact (of the dogs... I assume you're limiting that type of contact between yourself and other dog walkers).
- If you have a dog that is high-risk for getting an infection, consider keeping it away from the park, reducing the amount of time it spends in the park or limiting off-leash time. This includes dogs with wounds, dogs that have recently had or are going to have surgery, dogs with active skin disease, dogs on immunosuppressive therapy (such as steroids), and dogs on antibiotics, among others.
More information about MRSP can be found on the Worms & Germs Resources page.
Reptile warning changes proposed in Texas
The Texas Department of State Health Services has proposed a series of changes to warnings that are already required of retailers that sell reptiles. The warnings are focused on prevention of salmonellosis, and retailers must post signs and provide written warnings to anyone buying a reptile about the risk of salmonellosis from reptiles.
Signs must include the following recommendations (new or revised text is underlined):
- People should always wash their hands with soap and running water after handing reptiles or reptile cages or after contact wtih reptile feces or the water from reptile containers or aquariums. Wash your hands before you touch your mouth.
- Persons at risk for infection or severe complications of salmonellosis, such as children younger than 5 years of age, the elderly, and persons whose immune systems have been weakened by pregnancy, disease or certain medical treatments should avoid contact with reptiles and any items that have been in contact with reptiles.
- Reptiles should be kept out of households or facilities that include children younger than 5 years of age, the elderly, persons whose immune systems have been weakened by pregnancy or disease, or certain medical treatments. Families expecting a new children should remove any reptile from the home before the infant arrives.
- Reptiles should not be allowed to roam freely throughout the home or living area. Wash and disinfect surfaces that the reptile or its cage has contacted.
- Reptiles should be kept out of kitchens or other areas where food and drink is prepared. Kitchen sinks should not be used to bathe reptiles or to wash their dishes, cages or aquariums. If bathtubs are used for these purposes, they should be thoroughly cleaned and disinfected with bleach. Wear disposable gloves when washing the dishes, cages or aquariums.
- The sign must also contain a statement that reptiles may carry Salmonella bacteria, which can make people sick, but reptiles may not appear to be sick.
Image: Texas Horned Lizard, Phrynosoma cornutum (photo credit: Shawn Billerman, click for source)
Raccoons attack baby
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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.
Rabies treatment question
I recently had a rabies exposure and treatment question that's worth discussing. It was from a person in India whose young child had potentially been exposed to rabies. The child had a wound on her hand and a stray dog licked the area. It wasn't reported to the parents until a little while later. Three doses of rabies vaccine were obtained and the vaccine series was started a few days after the potential exposure.
Here are some issues:
- Was this child actually exposed? It's hard to say. It's probably unlikely that rabies virus was inoculated into the child in a situation like this, with relatively minor skin lesions and fairly brief contact with the dog. However, contact of saliva from an infected animal with broken skin is a potential route of infection so, even if it's unlikely, you have to err on the side of caution and consider the child exposed.
- Standard recommendations for post-exposure prophylaxis are 4 doses of vaccine on days 0, 3, 7 and 14. Three doses might be effective but it's hard to have confidence in it, especially when dealing with an almost invariably fatal disease. Trying to get ahold of a 4th dose would be best in a situation like this.
- It doesn't appear that rabies antibody was administered at the start. Standard protocol is to give anti-rabies antibody with the first vaccine dose. This provides an antibody boost and early protection while the vaccine is taking effect. The antibody can still be used even if it wasn't given with the first dose of vaccine, as long as it's within the first week. After that, it's assumed to have limited effect because antibodies from vaccination would be increasing. It's probably more important with serious bites and bites near the head and neck, where the onset of rabies can be earlier, but getting a dose of antibodies within the first 7 days would still be recommended.
- Did the dog actually have rabies? That's the big question. When someone is potentially exposed, the best thing to do is to identify and quarantine the biting dog. If the dog had rabies and was shedding rabies virus in saliva, it will show signs of rabies within 10 days. Therefore, if you quarantine the dog and it's healthy after 10 days, it didn't have rabies and no post-exposure treatment is necessary. In this case, it's a stray that was known in the area, and it seems the dog was still around and healthy 15 days after the exposure. So, as long as there is 100% confidence that the dog is actually the same one, then post-exposure treatment is not necessary. The trick is being 100% confident that it's the same dog.
Leptospirosis death: UK
British champion rower Andy Holmes has died of leptospirosis, which was suspected to have been acquired from the water during the annual Boston Rowing Marathon on the River Witham (UK) in September. The 51-year-old Holmes, an accomplished Olympic rower from the 1980s, started to feel unwell in the days after the race, and developed a fever. He was subsequently diagnosed with Weil's disease, a serious form of leptospirosis that can cause liver failure.
In some ways, this is being written off as a very rare and unfortunate event. It's always hard to determine how aggressive to be when making recommendations about avoiding infections that can be acquired from common recreational and occupational activities.
The race's welfare officer stated "Part of any rower's training is being warned about water safety. If you fall into water you must wash thoroughly and if you think you have ingested any water seek medical advice." The problem is, exposure to water during rowing and similar events is basically unavoidable. Splashes of small amounts of water into the eyes, nose, mouth or cuts/scrapes could be enough to inoculate potentially harmful microorganisms into the tissues. People aren't going to run to the physician after every potential exposure. Knowing whether or not the water source has previously been implicated in leptospirosis infections may be useful, but it doesn't tell you anything for certain.
General recommendations for people working around water include:
- Covering cuts and sores with waterproof bandages.
- Washing hands, particularly before eating.
- Avoiding contact of water with the eyes, mouth and nose, whenever possible.
- Avoiding ingestion of any amount of water.
- Ensuring their physician knows about the potential for water exposure should they become sick.
Obviously, complete avoidance of water exposure is impossible for many people, and the overall risk is very low. Weil's disease is a rare condition but it does occur, both as sporadic cases and large outbreaks. It's usually treatable but can be fatal, so it shouldn't be dismissed.
Issues with pets and leptospirosis are similar. Pets, mainly dogs, become exposed from contact with water that has been infected by Leptospira bacteria from the urine of infected wildlife. Infection can cause a broad range of disease in dogs as well, from subclinical to acutely fatal. Vaccines for certain strains are available for dogs who are at higher risk of exposure. Talk to your veterinarian about whether your dog should be vaccinated against leptospirosis. More information about leptospirosis in dogs and cats is available on the Worms & Germs Resources page.
Image: Andy Holmes sits behind Steve Redgrave after winning a gold medal for Britain at the 1988 Seoul Olympics.
