Scott Weese
Scott Weese is an Associate Professor in the Department of Pathobiology at the University of Guelph, and Public Health and Zoonotic Disease microbiologist for the University's Centre for Public Health and Zoonoses. After graduating with a Doctor of Veterinary Medicine degree and spending time in private practice, he completed an large animal internal medicine residency and Doctor of Veterinary Science graduate program. He is board certified in internal medicine by the American College of Veterinary Internal Medicine and is Chief of Infection Control at the Ontario Veterinary College Teaching Hospital. He has an active research program focusing on infectious diseases, particularly those that can be transmitted between animals and people. He lives outside of Guelph, Ontario with his family and a collection of pets, including a dog, cat, fish and a herd of rare-breed sheep.
Human vaccinia infection from rabies bait exposure
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Rabies baiting is a highly effective way to reduce rabies in wildlife populations. As we've discussed before, this involves dropping edible rabies vaccine. These baits are dropped in rural areas but there is the potential for curious people to come into contact with the vaccine if they handle baits that they come across. It is recommended that people avoid contact with the baits and wash their hands if they do come into contact with it because the baits contain a live virus. They do NOT contain live rabies virus. Rather, they contain vaccinia virus that has been manufactured to produce immunity to rabies virus. The risk of human infection is low, but as we constantly get reminded with infectious diseases, low doesn't mean no.
Today's MMWR reported a case of human infection associated with rabies bait. In August, a 35 yr old Pennsylvania woman was picking berries and her dog found a rabies bait. The dog punctured the bait packaging and the woman subsequently handled the bait. She washed her hands, but it took ~30 minutes for her to reach somewhere to wash them. This person had a few factors that put her at higher risk of developing an infection. She had some skin lesions on her hands from berrry thorns, which could increase the risk of infection. She was also on multiple immunosuppressive drugs.
The day after exposure, her doctor took blood samples for rabies and vaccinia virus antibodies and examiner her hands. Skin lesions (papules...little bumps) developed 3 days later. These were tested and vaccinia virus was identified. The skin lesions progressed and she was hospitalized a couple days later. She was treated with antibodies against vaccinia virus (because of the progression of disease and her compromised immune system). She went on to develop muscle aches, headache and developed a swollen lymph node, and was treated with more antibodies and an experimental antiviral drug. She responded to treatment and was discharged from the hospital on day 19.
This is the 2nd reported human infection from rabies baiting. Considering the millions of baits that have been dropped and presumed relatively large number of people that have had some contact with the baits, the overall risk of disease is low. This person was at high risk because of her immunocompromise, and it's likely that an otherwise healthy person would not have developed an infection like she did. The big problem here was her contact with the bait. She did everything right after that...washed her hands as soon as she could, called the Dept of Health, went to her physician and ensured that testing was done, but still got sick.
Avoid rabies baits. The risks are low but why take any risk? People that have compromised immune systems or skin diseases should take particular care. If you've been exposed to rabies bait, wash your hands ASAP and contact health authorities to determine if anything should be done.
How to diagnosis influenza in pets
One of the common questions accompanying the onslaught of calls I've taken today is "How do you diagnose influenza in pets?"
Clinical signs, such as sneezing, coughing, fever and lethargy, are not useful for diagnosis. Influenza can produce highly variable disease, ranging from almost none to very severe - so you can't look at an animal and say it has influenza just based on the clinical signs. We don't know much about H1N1 influenza in different animal species (including pets), but this type of influenza can probably cause a wide range of disease in animals as well (at least in those it can infect).
The presence of someone in the household with influenza should get you thinking about flu in a sick pet, but it is far from diagnostic. Many, many people have influenza, but very few pets do. There are many other diseases that can produce signs similar to influenza in pets. The health of people in the household is an important thing to know, but we can't jump to conclusions based on the household history alone.
Laboratory testing is required for the diagnosis of influenza, and there are a few options:
- PCR testing of nasopharyngeal (throat) or nasal swabs, or fluid collected from the trachea: This molecular test detects influenza virus RNA. This is the fastest test and it is most sensitive when samples are taken early in disease.
- Serology: This involves testing blood for antibodies against influenza. Two samples are taken 10-14 days apart. If the antibody level rises 4-fold or greater, that is indicative of influenza infection. This is considered the most reliable method of diagnosis but takes time.
- Virus isolation from nasopharyngeal or nasal swabs, or tracheal fluid: Samples are inoculated into eggs to try to grow the virus. This can take quite a while and isolation of the virus can be difficult.
H1N1 in a cat
H1N1 influenza has been confirmed in a cat in Iowa. The cat had "influenza-like illness" and was tested, with H1N1 being confirmed today. Two of three people in the house were also sick, but they became ill before the cat, and were presumably the source of infection for the cat. There's no evidence that the cat has infected anyone.
This doesn't really change anything that we've been recommending regarding H1N1 and pets. H1N1 infection is pets is rare but has been diagnosed in ferrets, and now in a cat. Considering the large number of infected people and the presumably large number of exposed pets, the risk of transmission to pets appears to be extremely low. Low doesn't mean no, however, and taking basic precautions is still wise.
Basically, remember that your pets are part of the household - microbiologically as well as socially. If you are doing something to reduce the risk of transmission of infection to people in the household, act the same way around your pets. Reduce contact with pets if you are sick. Avoid being around them when you are coughing. Wash your hands frequently. Avoid contact with their faces. If your pet gets sick after you've had H1N1 (or any other infection) make sure your veterinarian is aware of it.
Image source: icanhascheezburger.com
'Registered' service dog scam
I've written a few times in the past about the need for better definitions and guidelines for service dogs. Service animals are incredibly beneficial for some people, but there is great potential for abuse of the "service animal" designation by people who don't really need a service animal and/or are using completely untrained and sometimes inappropriate animals.
An example of such unscrupulous behaviour is RegisteredServiceDogs.com. At this site, you can enter your pet's name and your information, and get a form for your physician to sign requesting the dog be authorized as a service animal - but there is no such process, and this company has absolutely no authorizing power! Additionally, there's a place for a vet to sign affirming that the dog being "registered" has had all shots required by the state and that, to the best of the vet's knowledge, it will not be a threat to the general public. There is no mention about whether the dog is healthy, is well-trained, is specially trained as a service animal, has undergone any real scrutiny to determine whether it could be a "threat to the general public", or anything else that should be a requirement for a true service animal. In other words, this company does absolutely nothing to ensure that the animal is an appropriate service animal. For their overwhelming effort of providing you with a form to fill out, they charge $49.95 to send you a worthless card saying your dog is a "registered service animal".
Anyone who has a real service animal has no use for a card such as this. If they run into someone who inappropriately tries to restrict their access, they're better off with information from the agency that trained the animal or, in the US, a copy of highlights of the ADA, since restriction of service animals is illegal.
If this company was really in it to help the cause of service dogs, it would have some standard criteria to ensure that the animals it certifies as service dogs are really service dogs. Otherwise, it's a money-grab to provide a useless card to people with true service animals, and a way to help people who just want to take their pets with them to places where they are banned. None of this helps the cause of true service dogs. It is a disgrace.
Anyone with a service dog that has questions or concerns about access should contact the agency that trained their dog or another reputable (non-profit) source of information such as Delta Society.
Image source: www.guidedogsofamerica.org
Another ferret flu case
A second ferret in the US has been diagnosed with H1N1 influenza. The latest case involves a fatal infection in a ferret from Nebraska that was presumably infected by its owner. Three other ferrets in the household were also sick, and it's fair to assume that they had H1N1as well.
It's important to keep things in perspective. We have two confirmed pet cases among thousands and thousands of human cases. Thousands of pets have presumably been exposed to owners infected with H1N1, with few apparent problems. (You can never rule out additional cases completely, because pets tend to get ignored in outbreak investigations, but there's no indication that this is a major problem.)
This is yet another good reminder of the potential for diseases to move between species in households. If you are sick with a potential infectious disease, you should restrict contact with household members - all household members: human and animal. Ferrets are likely the greatest risk when it comes to H1N1, followed by pigs and pet birds. Dogs and cats are presumably low risk, but we can't say there's absolutely no risk.
If you might have H1N1, reduce close contact with your pets. Don't hide from them, but avoid close face-to-face contact and coughing around them. Wash your hands regularly. More details about household infection control precautions are available from the CDC. Take the same precautions around pets as you would around people. If your pet subsequently gets sick, make sure your veterinarian knows about the possible H1N1 exposure.
Image source: www.ferretfriends.org
Group A strep and dogs
I was asked this the other day, in regards to a post about pets and recurrent strep infections in people: "You listed a few things to remember and one of them was how the pet might be an "innocent bystander infected by a family member." Is there any indication that a dog might get sick from licking a person infected with Group A Strep?"
Streptococcal infections in dogs are very rare. When they occur, they are typically caused by Streptococcus canis, a Group G strep. Group B strep infections have also been reported. I'm not aware of any reports of Group A (Streptococcus pyogenes) infections in dogs, despite the fact that exposure is probably very common.
Group A strep is a predominantly, if not exclusively, human pathogen. It can be found in healthy individuals (e.g. in the throats of 10-15% of healthy kids) and is the main cause of strep throat. Group A strep also causes invasive infections such as cellulitis, various soft tissue infections, and in rare circumstances, necrotizing fasciitis (flesh-eating disease). Considering how commonly healthy people carry this bacterium and how common strep throat is, you have to assume that dogs are frequently exposed to this bacterium from household contacts.
Licking a healthy human carrier would certainly create an opportunity for a dog to be exposed. Licking wounds of patients with strep infections would probably be worse. Since exposure is probably common and we don't really identify problems in dogs with this bacterium, the risk of infection in dogs is presumably very low. However, basic measures should always be used to reduce the risk of exposure to infectious agents. Even though we don't recognize Group A strep as a problem in dogs, you don't want your dog to be the first case. Dogs shouldn't be allowed to lick infected wounds for both the health of the dog and the person. Strict avoidance of people with strep throat doesn't make sense, but licking should perhaps be avoided since the sick person could also be at higher risk for a secondary infection from the multitude of bacteria present in the dog's mouth.
Bottom line... the risk of Group A strep infection in dogs is minimal, but basic hygiene practices can make the risks even lower.
Rabies death in Indiana
An Indiana woman has died of rabies. Little information is currently available. Reports state that bat rabies was involved but that the source of exposure was not known. Presumably, they have determined that she was infected by the bat rabies variant (strain), but she didn't report being bitten or otherwise exposed to a bat. Bat rabies is a serious concern because it is easy to get bitten by a bat and not know it. Most cases of rabies in Canada and the US are associated with bat exposure. This is a tragic reminder about why we pay a lot of attention to bats and rabies (and why my family received post-exposure treatment after having a bat in the house a few years ago).
More information about rabies can be found on the Worms & Germs Resources page.
No spleen + dog bite = beware
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.
More information about Capnocytophaga and bites can be found on the Worms & Germs Resources page and in our archives.
Pets and H1N1 revisited
The recent discovery of H1N1 influenza in a pet ferret has led to another round of concern about the potential impact of H1N1 on pets and pets as a source of human infection. Finding H1N1 in a ferret is not particularly surprising, considering ferrets are susceptible to various (including human) influenza viruses. We shouldn't dismiss the potential that certain pets could become infected by this virus or transmit, it but the overall risks are presumed to be very low. There have obviously been many, many cases of H1N1 influenza in pet owners, yet there is just this one report in a pet (although it's certainly possible that other pets have been infected but not diagnosed). Ferrets may be the biggest concern. Pet birds and pot-bellied pigs may also be at higher risk considering this virus can clearly infect pigs and birds. Cats are probably a bigger concern than dogs because of what we know about cats' susceptibility to (and ability to shed) H5N1 (avian) influenza.
The risks are low to pets and pet owners, but there's rarely a no-risk situation with infectious diseases. A few basic measures should be taken to reduce the risks associated with this pandemic virus:
- If you have (or think you may have) influenza, treat you pet like other people in your family. Avoid contact with them, especially their faces, and pay close attention to hygiene (especially handwashing). This should help reduce the risk of exposing your pet to H1N1.
- If you have influenza, or your pet has been exposed to anyone with influenza, and your pet becomes ill (e.g. respiratory disease, fever, lethargy), contact your veterinarian. Avoid close contact with your sick pet (especially the face) and wash your hands after you handle it.
- Relax and enjoy the company of your pet. The risks of influenza are low.
Horse Strep in a person via a dog
Streptococcus equi subspecies zooepidemicus (usually just called Strep zooepidemicus) is a common cause of infection in horses. It is an "opportunist" that is often found in healthy horses, but which can cause disease in certain situations. While horses are the natural host of this bacterium, sporadic infections and outbreaks are occasionally reported in dogs at cats, particularly in shelters or other crowded situations. Severe (including fatal) pneumonia can occur, as was reported in a recent outbreak in a humane society in Ottawa. Rarely, S. zooepidemicus can also cause infections in people.
A report in the Journal of Medical Microbiology (Abbott et al) describes a serious S. zooepidemicus infection in a person, that was traced back to a dog. The dog lived on a farm that also had horses. It developed pneumonia and S. zooepidemicus was isolated from its respiratory tract. The dog was treated and recovered. However, the dog owner also became ill with fever, headache, a stiff neck and general malaise. Penicillin was prescribed, but the person's condition did not improve and he/she ended up in the hospital. Streptococcus zooepidemicus was also isolated from this person's nose and throat. When the dog and human strains were compared using molecular tests, they were related. An investigation of the farm was performed, and while all the horses present at the time were negative for S. zooepidemicus, the bacterium was isolated from a healthy dog.
This is a rare situation and one that shouldn't result in too much concern. It does highlight a couple points that are good to remember:
- Getting cultures is very important for obtaining a diagnosis.
- Animal contact and pet health should be considered whenever someone is sick with a potential infectious disease. Physicians need to know whether their patients have contact with animals. They need to be told if a sick animal is present so they can consider whether the pet and human illness might be related. Knowing to what someone may have been exposed might speed up diagnosis and appropriate treatment.
- Rare things are rare, but they happen. We shouldn't focus on rare events but we have to keep our minds open and recognize that strange things happen with infectious diseases.
