Worms and Germs Blog : Animal Health & Diseases : University of Guelph : Ontario Veterinary College : Zoonotic Diseases : Guelph, Hamilton, Ontario

"NDM-1 superbugs" have received a lot of press the last day or two. That's lead to questions about whether there may be any risks for pets.

It's good to see that people are thinking about how this might affect other animal species. That's a thought process that would have been rare a few years ago, and which was probably fostered by the emergence of MRSA in animals.

What it NDM-1?

• NDM-1 stands for New Delhi metallo-beta-lactamase 1. It is a type of beta-lactamase, an enzyme that inactivates certain antibiotics (those of the beta-lactam class). The concern with NDM-1 is that it inactivates carbapenem antibiotics, an important class of drugs that is often used to treat serious and life-threatening infections.

Where is it a problem?

• It's currently mainly a problem in India and Pakistan.

Will is spread to other regions?

• Probably. It's easy for people to travel around the world quickly, and it's easy for new microorganisms to travel with them. A bug that originates in one region can very easily spread across the planet. NDM-1 has been found in a few other countries, including Australia, parts of Europe and Canada. There is concern that the increase in health tourism (traveling to countries like India for cheap and quick procedures like elective surgeries) will result in spread of NDM-1, since people could pick up the bug in hospitals and bring them home. Transmission of NDM-1 in hospitals from patients that had healthcare procedures abroad has been documented in the UK. People traveling to regions where the organism is present for other reasons are also possible sources.

Can it affect pets?

• Probably. Two important types of bacteria, E. coli and Klebsiella spp, can carry NDM-1 (and probably other related bacteria can as well). These can cause infections in many different species. As more people carry bacteria with NDM-1, there's a greater chance that pets will be exposed, as we've clearly seen with MRSA. Dogs that visit human hospitals and pets owned by people who visit India for healthcare are probably at greatest risk, with pets of people who have been hospitalized and pets of healthcare workers likely also at increased risk.

What can we do to reduce the risks?

• Nothing specific. The most important factor here is control of NDM-1 in human hospitals. At the animal level, there's nothing in particular we can do about NDM-1 at the moment. The keys are prudent use of antibiotics (to reduce the likelihood that resistant strains will get established in pets), good general infection control in households and veterinary hospitals (to reduce opportunistic infections by bacteria that can carry NDM-1), and making sure that cultures are taken when infections are present (to find out if/when this becomes a problem).

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Recently, Kings of Leon canceled an outdoor concert after a pigeon (with very good aim, apparently) in the rafters above the stage managed to poop on band members, including one shot that hit the face of the band's bassist.

Besides, the "ick-factor," what are the concerns?

Various studies have found potentially nasty microorganisms in pigeon poop, including:

• E. coli
• Various microsporidia
• Various Cryptococcus species
• Multidrug resistant Staphylococcus spp
• Salmonella
• Chlamydophila psittaci
• Mycobacterium avium complex

The risk of disease is pretty low for most people, and we are potentially exposed to many of those bugs on a daily basis. The risks increase with higher ingested doses (so direct-deposit of poop is a much greater concern that inadvertent contamination of your hands) and in people with compromised immune systems. It's unlikely but not impossible that someone would get sick from exposure to pigeon feces, and don't eat poop is a good general philosophy for life.

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Infection control is a constantly evolving and expanding area - for the good. Paying close attention to infection control in human hospitals is a relatively recent phenomenon, and the advances in infection control are now having an impact outside of hospitals. Pandemic H1N1 influenza drove a lot of changes, but there's been a general increase in awareness of the need for routine infection control in the greater community. This applies to veterinary clinics and living with animals, but is also evident in everything from protocols in workplaces to summer camps.

We're getting ready to send my oldest daughter to summer camp for 12 days. Back in my time, I doubt there was much of an infection control plan for summer camps. If anything, it was probably "don't puke on the other campers and try not to eat too much dirt."

Oh, how things have changed! Last night, we received an email from the camp reminding us to keep our daughter at home if she is sick and outlining their infection control program. Among the infection control measures are:

• Having 2 12-foot handwashing stations outside of the Dining Hall, with everyone required to wash their hands before eating
• Having sinks equipped with handwashing supplies present in all buildings
• Having hand sanitizers throughout the Dining Hall and in every cabin
• Training staff in infection control protocols
• Cleaning cabins every day, with daily inspections of cabins by their "Public Health Supervisors"
• Daily spraying down of surfaces like Dining Hall tables, door handles, toilet handles, taps etc. with disinfectant
• Screening of all kids by one of the Registered Nurses on the first day of camp

Pretty impressive effort, in my opinion. Like everything else, compliance is critical and having good facilities and plans doesn't guarantee good practices, but the efforts put into developing this program and communicating it suggest that they'll be paying attention to it. Even with a good program, camps are an excellent breeding ground for infectious diseases and are perpetually an outbreak waiting to happen, but a good infection control program should greatly reduce the risks.

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Streptococcus zooepidemicus is an important cause of infections in horses. This bacterium can also be found in healthy horses. When you consider the large number of horses that are infected and the larger number of healthy horses that are carriers, along with the close contact that people have with horses, it's pretty obvious that people are regularly exposed to "Strep zoo". This bacterium is not well-adapted to survive in people and cause infections, so human infections are quite uncommon, but they can occur. There are periodic reports of S. zooepidemicus infections in people, with varying degrees of association with horse-contact.

An upcoming edition of journal Epidemiology and Infection contains a report of S. zooepidemicus meningitis in a 51-year-old woman (Minces et al, 2010). This person had a mild upper respiratory tract infection, then developed signs of meningitis (including fever, unresponsiveness, respiratory distress). A spinal tap was performed and S. zooepidemicus was isolated. The woman fortunately responded to treatment and recovered.

Upon initial questioning of the patient's mother, no animal contact or ingestion of unpasteurized dairy products (another risk factor) was reported. However, it was later revealed that the woman's daughter had started horseback riding at a friend's farm approximately one month earlier. The type of contact that the woman had with horses (if any) at the farm was not reported, nor was there any investigation of S. zooepidemicus shedding by horses on the farm.

Based on the fact that this is typically an equine-associated bacterium and the history of contact (albeit potentially limited or indirect) with horses, horse contact was blamed for the infection. It's a reasonable conclusion but it's far from certain because of the nature of the contact, the lack of any proof of the same strain of S. zooepidemicus in horses on the farm, and previous reports of infections occurring in people with no contact with horses.

Exposure to S. zooepidemicus is an inherent risk of having contact with horses. It's nothing to lose sleep over and is probably relatively low on the list of potential health problems associated with horse contact. The risk is probably greatest in people with compromised immune systems and other general risk factors for disease such as advancing age and pregnancy. Good general hygiene measures, avoiding contact with sick horses and close attention to hand hygiene probably minimize these already low risks.

(click image for source)

This Worms & Germs blog entry was originally posted on equIDblog on 25-May-10.

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Never a dull moment...

This morning the Toronto Star published an article about the intended euthanasia of 350 animals at a humane society in Newmarket due to an ongoing ringworm outbreak.  This was quickly followed by another article about the same event that gave a few more details, including some comments from the OSPCA chief executive officer Kate MacDonald, who confirmed that the euthanasias had begun.  A "very aggressive strain" of ringworm and "human error" (related to a breakdown in protocols) are currently being blamed for this morning's actions.  A lot of people are (understandably) very upset.  No one ever wants to see an infectious disease outbreak come to something like this.

I’m hesitant to comment too much at this stage, because we still don’t have all the facts - apparently even the duration of the outbreak is unknown.  No one has said if all 350 animals are infected (or what percentage of them are), nor how many other animals are present at the shelter. We also don’t know what’s already been tried in terms of controlling the outbreak.

A few facts about ringworm (dermatophytosis) that people need to remember:

• Ringworm is a skin infection that can be caused by several species of fungi.  It is not a "worm" at all.  It is also very easily transmitted by direct or indirect contact with infected animals - their fur, their cages, their blankets, or anything else that may be contaminated with infected skin cells or hair.  Such infectious material can even be spread over short distances (e.g. room to room) in dust that is stirred up into the air.
• Ringworm is transmissible to people, so with a large outbreak there are also issues with staff safety, and concerns with adopting out infected animals.  For most people ringworm infection may cause itchy, uncomfortable skin lesions, but for higher-risk people (e.g. very young children, the elderly or immunosuppressed individuals) the infection can be much more serious.
• There are also a lot of animals (particularly cats) that carry ringworm without showing any signs of infection. If the Newmarket shelter has 350 animals with clinical signs of ringworm (a detail about which we have no information right now), that’s pretty bad, but even the animals who don't appear to be infected may be carrying the fungus and could spread it to others.
• Crowding, close contact and warm, humid environments are all factors that increase the risk of ringworm transmission. These are also all factors that are very hard to control in a crowded animal shelter.
• Ringworm is treatable, but it is not cheap or easy. Animals typically require systemic therapy (usually oral medication, which can be very expensive particularly in large dogs) as well as whole-body topical therapy (e.g. dips, shampoos, sprays), and they need to be treated for several weeks. Decontamination of the environment at the same time is critical to prevent reinfection.

Cleaning up a ringworm outbreak at a shelter with at least 350 animals is no small undertaking.  The second article in the Star also describes personnel at the shelter this morning wearing "white hazardous material suits, latex gloves and plastic covers over their shoes", which would be considered reasonable precautions for entering a highly contaminated environment.

I'm sure we'll hear more about this in the days to come, and hopefully that will include more details about why the mass euthanasia was deemed necessary by the OSPCA.

For more more information about ringworm, download the information sheet from the Worms & Germs Resources page, or check out our archives.

Photo source: yorkregion.ontariospca.ca via www.thestar.com

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A 62-yr-old Italian woman has died from psittacosis, an infection caused by the bacterium Chlamydophila psittaci. Sometimes called "parrot fever," psittacosis is an uncommon but important disease linked to contact with birds, particularly psittacines (e.g. parrots, parakeets, cockatiels). In people, C. psittaci usually causes flu-like respiratory disease, but severe pneumonia and encephalitis (inflammation of the brain) can occur in some individuals. With prompt diagnosis and treatment, mortality (death) rates are very low (<1%), however mortality rates are higher when diagnosis and proper treatment are delayed. It's not clear in the this case whether psittacosis was considered early in disease nor when treatment was initiated.

Chlamydophila psittaci can cause illness in birds, but it's also carried by a variable percentage of healthy birds, mainly psittacines. This complicates control of the disease, since you can't tell which birds are carrying the bacterium without testing them all. In this case, the woman's parrot died a few days before she became ill. It's not clear from the brief report whether the bird was diagnosed with C. psittaci infection, however this is a good reminder of the need to consider pet and owner health in parallel. It also indicates why diagnostic testing is important when pets are sick, or even after they've died.

If a pet becomes sick, knowing what caused the disease might be of relevance to human health. Also, if physician's ask about illness of any other individuals in the house, this should include pets, as they might get some relevant information.

In a case like this, if the bird was diagnosed with C. psittaci infection and the owner developed flu-like illness shortly thereafter, it should have been a strong indication that the person might have psittacosis, allowing for early treatment. Alternatively, even without a diagnosis, knowing that the person had a pet parrot (a risk factor for psittacosis), and that the bird had died shortly before the woman got sick, could lead to recognition that both diseases could be linked, and could lead to earlier consideration of psittacosis.

This unfortunate event should be taken as yet another reminder of the need for veterinary personnel and human physicians to communicate more effectively, and that physicians need to know about pet contact and pet health when evaluating their patients.

Image: African Grey Parrot (Psittacus erithacus erithacus). (Photo credit: Eli Duke)

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A somewhat controversial study has just been published in the Journal of Veterinary Emergency and Critical Care (Savigny et al 2010). The study looked at the use of Tamiflu (oseltamivir) for the treatment of parvovirus infection in dogs. Tamiflu is best known as a potentially important influenza drug in humans. It's a neuraminidase inhibitor that can prevent replication of some viruses, such as influenza. It actually has no effect on parvovirus, but has been used by some veterinarians based on the hypothesis that it can have an effect on bacteria and perhaps prevent secondary bacterial infections, which contribute to the severity of parvoviral disease.

The study examined a relatively small number of dogs (35) with parvovirus infection. Some dogs received Tamiflu along with standard treatments, while the others received a placebo and standard treatments. There was no difference in major outcomes between the two groups, but control dogs lost more weight during treatment.

The study has some weaknesses and doesn't tell us too much, but it's the first objective investigation of this drug in dogs. There was no significant difference in relevant outcomes, but was that because the drug doesn't work, because the dose was too low (as has been suggested by some) or because the study was too small to detect a real difference? That's the big question.

Some veterinarians are completely convinced Tamiflu works for parvovirus infections and disregard any suggestion that it doesn't. Currently, there is no scientific evidence whatsoever supporting its use, and this study doesn't help much one way or the other. There are abundant anecdotes, and it's plausible that this drug could be useful for treating this disease, but there are a few concerns:

• We really don't know whether it works. Continuing to use a treatment in the absence of objective information is not necessarily a good idea.
• We don't know the appropriate dosage and duration of treatment for dogs. We also don't know which animals Tamiflu might or might not help. It is probably most effective (or perhaps only effective) early in disease.
• Tamiflu is an important human influenza drug, and resistance is emerging in influenza. Can we justify using a drug that is a part of pandemic influenza control for the treatment of canine parvovirus, without any evidence that it is effective or needed?

The article's abstract concludes by saying "Based on these results, the true role of oseltamivir in the treatment of parvoviral enteritis remains speculative, although it is believed that further investigation is warranted."  Very true.

We need two things:

• Rational discussion about whether use of drugs like this is justifiable in animals.
• Better studies to tell us whether it works, and if so, how to best use it.

If we end up using it, we also need surveillance to make sure routine use of this drug in animals doesn't contribute to resistance in humans. Unfortunately, the Tamiflu debate is too often full of anecdotes and arguments as opposed to logical discussion and sound evidence. Hopefully that won't get in the way of someone doing a more definitive study.

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When the novel H1N1 influenza pandemic infected large numbers of people, it was not particularly surprising that the occasional infection was noted in pets, considering over 50% of North American households have pets, and the close nature of contact that many people have with their pets. While the few cases that occurred were highly publicized, in the end pet infections were rarely diagnosed (although that doesn't mean they were truly rare), and limited information about these cases has been available. Details regarding one H1N1-infected cat from Iowa (Sponseller et al. 2010) were recently published in Emerging Infectious Diseases.

Here are some of the highlights:

• The 13-year-old cat was an indoor cat that was admitted to Iowa State University's veterinary hospital because of depression, decreased appetite and signs of respiratory disease.
• Two of 3 people in the house had undiagnosed influenza-like illness a few days before the cat got sick. The cat was an affectionate pet and interacted closely with household members.
• Influenza was diagnosed in the cat by detection of H1N1 influenza virus using molecular diagnostic methods (reverse transcriptase PCR) on a sample of fluid collected from the lungs.
• The cat improved with supportive care alone (mainly intravenous fluids to correct dehydration).

Considering the cat lived indoors and people in the house had signs consistent with influenza, it's almost certain that the cat was infected by its owners. This isn't surprising, but it's a good example of how infectious diseases can move between people and pets, in either direction. There's no evidence that pets were a source of human infection, but if something can move from people to pets, there's certainly good reason to think that it could go back from pets to other people. This should be another wake-up call for the need to consider and investigate the potential role of pets in any emerging infectious disease, and to consider emerging "human" diseases in sick animals that might have been exposed.

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Heartworm is an important problem in dogs. It's a parasitic disease caused by Dirofilaria immitis and is spread by mosquitoes. It can cause serious, even fatal disease, and routine testing and preventive medication is an important thing for dogs in areas where D. immitis is present. Dogs (wild and domestic) are the natural host for this parasite, but other species can be accidentally infected, including people and cats. People become infected by being bitten by a mosquito that is carrying the parasite, having acquired it from an infected dog. Human infections seem to be quite uncommon and, interestingly, while this is a serious problem in dogs, it tends to be rather innocuous in people. In fact, the biggest problem with heartworm infection in people is the fact that it can be confused with other, more serious problems, leading to invasive testing.

After infecting someone, D. immitis works its way to the blood vessels in the lungs. This can result in  a small area of inflamed tissue in the area. If a chest x-ray is taken, a "coin lesion" (a small, usually 1-3 cm spot) is often present. The parasite infection usually doesn't cause any problems in people, but lung cancer and tuberculosis can look the same on x-rays. Usually, open-chest surgery ends up being performed to get a biopsy of the area because of the concerns about cancer. In heartworm cases,the biopsy identifies the problem as D. immitis, which is much better than cancer, but the risks associated with having undergone such an invasive procedure are much greater than that of the parasitic infection itself.  

Typically, treatment is not recommended in people because the infection rarely causes problems and people are "dead end" hosts, meaning they cannot pass on the infection. (Unlike in dogs, infected people don't have the parasite microfilaria in their blood, which is how the infection is passed on to  mosquitoes and other animals).

Heartworm is a rare and rather innocuous problem in humans - it's nothing to lose sleep about.

Image: A diagram of a very severe case of heartworm in a dog, in which there are so many worms in the pulmonary arteries that there is "back-up" of the parasites into the right side of the heart, which is how the parasite got its common name.

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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

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The latest edition of the journal Emerging Infectious Diseases contains a paper describing the 2008  Australian Hendra virus outbreak in horses and people.

In this outbreak, there were five horses infected and two humans infected. The horses predominantly had signs of neurological disease, not respiratory disease like some other reports describing this disease. Four horses died. One recovered but was euthanized for public health reasons.

Two people became infected after working with the sick horses, which represents 10% of the total veterinary staff that were exposed to the infected horses.  Both people started off with influenza-like illness, which seemed to improve initially, but then signs of severe neurological disease developed. They were treated with ribavirin, an antiviral drug, as part of an experimental treatment. One of them died after 40 days of illness, the other person survived.

The authors stressed that the effectiveness of ribavirin could not be determined, but they recommend it nonetheless because of the severity of Hendra virus infection and lack of other options. Ribavirin was also used in the 2009 outbreak, but it is clearly not 100% effective since one person died there also.

A number of concerning activities occurred that put people at risk of infection, including a "percutaneous blood exposure while euthanizing an infected horses" (they didn't explain exactly what this was, but it could have been a needlestick), low use of personal protective equipment, and contact with potentially infectious body fluids. This is unfortunately not surprising since the approach to infection control (particularly in terms of zoonotic infections) is often lax in equine medicine. That certainly has to change, particularly in areas where Hendra virus may be present.

Much more information about how to control this potentially devastating virus is needed. Fortunately, infections are uncommon and it is restricted to a fairly small geographic range in Queensland, Australia.

Image source: http://animalphotos.info/

This Worms & Germs blog entry was originally posted on equIDblog on 27-Jan-10.

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Just as I'm getting ready to go on vacation (that will hopefully involve some time on the beach), I read an article in the latest edition of Emerging Infectious Diseases about seagulls and beaches as reservoirs of multidrug-resistant E. coli (Simoes et al 2010). In this study, the researchers collected seagull poop from beaches in Porto, Portugal and tested them for the presence of extended spectrum beta-lactamase (ESBL) E. coli, a highly drug resistant form of this common bacterium. Thirty-two percent (32%) of the E. coli they isolated were ESBL, a pretty impressive rate in wild birds that would not be directly exposed to antibiotics. Various E. coli strains were present, including some that can cause severe disease.

In some respects this is pretty concerning, and in other respects not too surprising. We know that birds in various (including remote) regions can carry multidrug-resistant bacteria. The ability of wild birds to carry these bacteria, combined with the wide geographic range that some bird species have, raises concern about the role of birds in the spread of antibiotic-resistant bacteria, as well as the potential for contracting a nasty drug-resistant infection while on the beach. Birds certainly have the ability to help spread certain types of bacteria over wide ranges. However, their overall role is probably very limited compared to the role played by people and (domestic) animals. For birds to become carriers of these bacteria, they have to pick them up from somewhere, which presumably doesn't occur until the bacteria have built up to a good level in people and/or animals. I doubt that birds account for many human infections. Antibiotic exposure through antibiotic residues in water or food sources could also play a role in the presence of these bacteria in birds, but that's an area that's not well understood. 

So, how does this influence my time on the beach? Not much. I wasn't really planning on having contact with seagull poop, and this paper just reinforces that basic precaution. Other basic measures such as keeping open sores covered, avoiding cuts by wearing shoes in rough areas or sand that might be contaminated with sharp objects, avoiding contamination of food with sand, avoiding areas with obvious bird poop contamination, and hand washing before eating and after leaving the beach are easy to do.

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A very poorly-written and confusing report suggests that another Streptococcus zooepidemicus outbreak is underway in dogs in a shelter in Ohio. Five of 175 dogs on the premises died suddenly of hemorrhagic pneumonia. The report variably mentioned a "virus that mutated from horses," that it's thought to be "not contagious" despite multiple dogs being affected, and that it's a "rare form of streptococcus" (a bacterium). Presumably, they are dealing with a group of dogs with Streptococcus zooepidemicus pneumonia (technically, Streptococcus equi var. zooepidemicus). This bacterium predominantly lives in horses but periodically causes infections in other species. Outbreaks in dogs are uncommon but have been reported in other shelters. I assume that cultures from the dead dogs identified the bacterium, otherwise other possible causes such as canine influenza would also have to be considered.

The statement about it not being contagious is bizzare. Obviously, it is contagious between dogs. It may have been referring to dog-to-human transmission, but while that's rare it has been reported.

The shelter is apparently treating all dogs with penicillin prophylactically (i.e. to prevent any more dogs from getting sick). There's no clear guidelines regarding management of S. zooepidemicus outbreaks in kennels. It's now known whether mass antibiotic treatment does anything helpful, but it has been used in other outbreaks. I think it's likely that these outbreaks stop on their own, rather than penicillin having a major impact, and that there's probably another underlying cause such as a viral infection to account for outbreaks of this rare disease. However, that's just speculation for now. Hopefully this outbreak will cease with whatever treatment and infection control measures they put in place (or on it's own). Hopefully a good review of routine infection control practices will be performed at the same time, as routine practices (or lack thereof) are often a major problem in shelters.

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H1N1 influenza was diagnosed in two dogs in China, bringing increased calls to pay attention to other animal species when it comes to this disease.

I'm more surprised by this than finding H1N1 in a cat or ferret. Dogs are susceptible to influenza and have their own circulating influenza strain (H3N8, originally from horses) but they rarely get other types of influenza. It's just an example of "rare things happen rarely, but they do happen." As with cats, it is now apparent that dogs are susceptible to this virus, although presumably minimally susceptible given the very low incidence of reported canine infections. This doesn't change our basic recommendations for dealing with H1N1: infected people should reduce contact with all individuals in the household, human or otherwise. People should be aware but not worried about the potential for pets to acquire H1N1. The risk of animals transmitting H1N1 back to people is unclear. It's theoretically possible but in practicality, a pet that gets H1N1 most likely got it from its owner, who's already exposed the rest of the household members as well.

Vaccination against canine influenza will not provide any protection against H1N1.

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Campylobacter bacteria are important causes of disease in people. Many Campylobacter species exist, and these different species vary quite a bit in their ability to cause disease in people and animals. Campylobacter jejuni is one of the most common causes of diarrhea in people worldwide, and is most commonly associated with contaminated food.  However, a few studies have reported that having pets (especially pets with diarrhea) is also a risk factor for Campylobacter jejuni infection.

Another Campylobacter species that may be of concern is Campylobacter upsaliensis. This species is primarily associated with dogs and cats, and a large percentage of healthy dogs and cats may be shedding this bacterium in their stool at any time. It doesn't seem to be a cause of disease in dogs and cats, but it may be an important and overlooked cause of disease in people. One study from the US reported that C. upsaliensis was the 2nd most common Campylobacter strain found in people with diarrhea (after C. jejuni). However, the true role of this species is unclear, partly because of common laboratory testing methods. Culture is the main method used to diagnose infection with Campylobacter, but this bacterium can be difficult to grow in the lab. Usually, culture media for Campylobacter contain antibiotics to inhibit other better/faster growing bacteria. Unfortunately, C. upsaliensis is often inhibited by these antibiotics, so it's likely to be missed in these cases even if it is there. Therefore, we might be underestimating the role of this Campylobacter species in diarrhea. This is an critical issue to investigate because C. upsaliensis is so common in dogs and cats, and it's important to determine what role pets play in human disease.

Avoiding Campylobacter infection involves some basic steps: avoid contact with feces, take care when handling diarrhea from pets, wash your hands regularly after handling pets and always wash your hands thoroughly after any contact with feces. Make sure your physician knows you have pets. In particular, if you have a pet with diarrhea or have recently acquired a new pet (especially a puppy or kitten), make sure Campylobacter infection is considered if you get diarrhea. Most infections are mild and go away on their own but some require specific treatment.

More information about Campylobacter can be found on the Worms & Germs Resources page.

Image credit: CDC/ Dr. Patricia Fields, Dr. Collette Fitzgerald

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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. This is the main option for diagnosis at this time.
• 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 of influenza in many species but takes time. It is not currently a viable option for pets because tests for pets are not available.
• 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. This is a method used by specialized labs with laboratory containment conditions appropriate for this virus and may not be readily available.

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Just when all those turkeys that managed to survive Thanksgiving weekend thought their troubles were over, there's new issue: H1N1 influenza (formerly known as swine flu) has been found in an Ontario turkey flock.  The H1N1 virus was first reported in birds in Chile in late August.

This is not a reason to panic.  No one can get the flu from eating a properly-cooked Thanksgiving turkey (nor from any other type of properly-cooked turkey).  The producer has voluntarily (and very responsibly) quarantined the affected flock, and no birds or eggs have left the facility.  There is no risk to the food chain.

Pigs can be infected by human, pig and bird flu viruses, and multiple infections can result in viruses trading genes and producing new viruses that can infect more species.  So it's not too surprising that H1N1can infect people, pigs and now birds as well.  This incident serves as an important reminder that we need to remain diligent about infection control and hygiene, even around animals.  It's highly unlikely that these turkeys had contact with infected pigs - most likely the virus was spread to this flock by a person.  Poultry producers may therefore need to consider getting vaccinated for H1N1 flu not only to protect themselves, but also their flocks, and anyone who may have the flu should definitely stay off these farms.  Hopefully the virus does not become established in wild bird populations (like H5N1 has in some areas), as this would make it much harder to control.

Recommendations for avoiding the flu (H1N1 or other) remain the same:

• Wash your hands and/or use alcohol-based hand sanitizer
• Sneeze into your elbow
• Disinfect commonly touched surfaces
• Stay home if you are sick
• Get vaccinated!

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When I talk about methicillin-resistant Staphylococcus pseudintermedius (MRSP), I usually say that the human health risks are low because human infections are very rare. However, rare doesn't mean it can't happen, as demonstrated by a case report entitled "Beware of the Pet Dog: A Case of Staphylococcus intermedius Infection" published in the American Journal of Medical Sciences (Kempker et al 2009).

This paper reports about a post-operative sinus infection in a 28-year-old woman. Cultures were taken and the bacterium was initially misidentified as a coagulase-negative Staphylococcus. It was then misidentified as S. aureus, and finally determined to be S. intermedius. In reality, that's probably another misidentification because the bug almost certainly was truly S. pseudintermedius. (It's become clear over the past couple years that S. intermedius is basically non-existent in dogs and that what has been called S. intermedius in the past is truly S. pseudintermedius).

It's important to remember that human infection with S. pseudintermedius is a rare event. Whenever you see a single case reported, you know it's a pretty uncommon or novel event. Further, this was a post-operative infection, not a spontaneous infection occurring in a low-risk person. At the same time, we need to make sure we don't completely ignore the potential risks. While the risk of transmission of S. pseudintermedius (including MRSP) seems to be very low, we shouldn't ignore it completely. Isolation and other strict measures aren't indicated when dealing with a pet with S. pseudintermedius infection, but general attention to basic hygiene practices and avoiding contact with the infected site is still a good idea.

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While in London (UK) last week, I went with a group of people to the John Snow pub. It's a bit of an epidemiologist pilgrimage, where you can sit in a pub named after one of the "fathers of epidemiology" and sign the guest book.

John Snow was a physician in London in the mid-1800's. Cholera outbreaks were a problem in Victorian London because of contaminated communal wells (for drinking water). Unlike many others, Snow did not believe in the miasma theory, which stated that noxious vapours in the air were the cause of many illnesses. While the "germ theory" of disease was not yet on the scene, Snow thought there must be some other way that diseases like cholera were transmitted, and he suspected (correctly) that the water supply was the problem.

During a cholera outbreak in 1854, he determined that a well in central London (Broad St, now Broadwick St) was a major source of the disease. Removing the handle from the pump (so that people could no longer use the well) stopped the outbreak.  Although Snow himself suggested that the outbreak was already in decline, removing that source undoubtedly played a large role in saving many lives. Back then (and even still commonly today), getting people to accept and adhere to infection control measures was not easy. After the outbreak ended, public officials fixed the pump, despite the fact that it was clearly associated with the outbreak. In hindsight, it's not surprising that this well was associated with disease, since it was shallow and very close to a cesspool.

The John Snow pub is located at the original site of the Broad Street pump.  You can see the location of the original pump from the window of the pub (there's a replica pump there and a marking on the ground at the exact site of the original pump). So, you can visit the source of a great cholera outbreak, peer out at the simple solution that helped stop it,  and have a drink in the pub named after John Snow - something that's more than a little ironic, since Snow was also famous as a teetotaler.

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Considering all of the disease outbreaks that have been attributed to petting zoos, including an outbreak in the UK this month that has sickened dozens and another in Vancouver that has affected at least 13 people, you would think that people who operate petting zoos would start to take the hint. Unfortunately, that's clearly not the case.

My family and I went to the Fergus [Ontario] Fall Fair today. Apart from the petting zoos, it was a great day, but the potential for ending up in hospital with a life-threatening infection shouldn't have to be a concern for fair attendees.

This fair had two petting zoos. One was also associated with a pony ride. We went there first and while my kids were looking at the animals, I noticed there was a table and a sign saying to use a hand sanitizer after touching the animals, but there were not actually any hand sanitizers available. I asked the attendant and he immediately started looking. They eventually found some, but we gave up after waiting a few minutes and went to the other petting zoo location because a handwashing station was set up there. Despite a large crowd around the first petting zoo, I didn't see anyone following our actions so presumably almost no one washed their hands after petting the animals. The good thing about this first petting zoo was they at least had a clean facility, appropriate animals and no major problems apart from the forgotten sanitizers.

Petting zoo number two was not as good. There were numerous problems, some of them very major.

• Inappropriate animals #1: As we walked in, someone held out a baby chick and tried to give it two my 2-year-old daughter to handle. Standard guidelines are that children under 5 should not handle young poultry, so these animals are inappropriate for any petting zoo.
• Inappropriate animals #2: The next thing we passed was a young calf. Calves are also considered a high-risk animal and should not be present in petting zoos.
• Inappropriate animals #3: The calf had diarrhea (see the diarrhea staining and hair loss probably associated with prolonged diarrhea in picture). It's very likely that this calf was shedding one or more infectious agents in its diarrhea, such as Cryptosporidium.
• Food for sale: Food was being sold and consumed inside the tent where the petting zoo was. This is inappropriate.

Petting zoos can be great events for kids. They can also be sources of large and serious outbreaks of infectious diseases. Hopefully nothing bad will come from this and we won't hear reports of illness in petting zoo participants. But, as I've said before, hope is not a proper infection control program.

Anyone running a petting zoo MUST know the issues, risks and proper preventative measures to take. Reading the Compendium of measures to prevent disease associated with animals in public settings would be a good start.

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Skin and soft tissue infections increasingly caused by highly drug-resistant bacteria, along with various concerns about antibiotic use, have led to a desire to find non-antibiotic approaches to treatment of these infections. Tea tree oil has some potent antibacterial properties when tested in the lab, and there are some studies indicating it might be effective for the treatment of certain infections. Some work that we've done in my lab shows promising activity of a few different essential oils against MRSP.  Some of these oil may be similarly useful treatments for certain infections. 

However, as I've stated before, we need to make sure that we adequately investigate safety of any new drug or therapy. All natural does not mean safer. If something kills bacteria, we need to make sure that it doesn't also harm an animal's cells and tissues.

Tea tree oil can cause damage to skin and soft tissue cells, but it's unclear whether this is really a problem during short courses of treatment. Nonetheless, in humans it has been recommended that tea tree oil not be used for treatment of burns because of concerns about tissue damage.(Faoagali et al, Burns 1997)

Another concern is toxicity from ingestion. This isn't usually a concern in adults, but there are a couple reports of children that became seriously ill (neurological abnormalities, progressive unresponsiveness... fortunately temporary) after ingestion of small volumes of tea tree oil. This leads me to have concerns about ingestion of the oil by dogs and cats if they lick areas where it has been applied, or eat bandages soaked in oil. They probably wouldn't ingest that much, but it's possible.

At this point, the jury is still out on the usefulness of tea tree oil. There are some potentially beneficial aspects and some safety issues that need to be clarified. In the interim, if you want to use tea tree oil:

• Recognize it's not a proven therapy. Don't use it in place of conventional treatment recommended by your vet.
• Keep it out of the reach of children and pets.
• Be judicious about the amount you use, and make sure pets don't lick it off.
• If the infected site seems to get worse after tea tree oil is used, stop applying it and see your veterinarian.

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A paper in the July 1 edition of the Journal of the American Veterinary Medical Association (Muller et al) describes a case of encephalitis (brain inflammation) in a rabbit caused by human herpesvirus type 1.  The owner had a severe herpes infection with genital and oral lesions five days before the rabbit got sick, and reported "intensive" nose-to-nose and mouth-to-nose contact with the rabbit. The rabbit started off with a decreased appetite and excessive tear production (epiphora) in one eye. Then other signs of eye and neurological disease developed. Despite aggressive treatment, the rabbit deteriorated and was euthanized after a week of hospitalization. Subsequent testing identified human herpesvirus type 1 in the rabbit's brain.

Human herpesvirus type 1, also called herpes simplex viruses type 1 (HSV-1), is a common sexually transmitted disease (STD) in people. It can cause oral, genital and ocular (eye) lesions. Humans are the primary host of this virus, but it has been found in species such as rabbits, rats, mice and chinchillas. In rabbits, it usually causes encephalitis, and is almost always fatal for these animals.

This case shows how viruses typically associated with one species can sometimes affect others. While we usually focus on microorganisms moving from animals to humans, they can also move in the opposite direction, as was presumably the case here. Close face-to-face contact with the infected owner was probably the source of the virus. This is an example of an uncommon event, but one that should not be ignored.

If you have an active herpesvirus infection:

• Limit close contact with rabbits (and, to be on the safe side, probably restrict contact with other pets as well). In particular, avoid contact with the mouth, nose or eyes.
• Wash your hands or use an alcohol hand sanitizer regularly, particularly after using the washroom or having any contact with infected sites/sores.
• Make sure herpesvirus infection is considered if your rabbit develops eye or neurological disease.

The risk of rabbits transmitting human herpesvirus is completely unclear. Common sense dictates that anyone hanlding a potentially infected rabbit should restrict contact with the eyes/mouth/nose, wear gloves, wash hands after contact (even if gloves were worn) and avoid contamination of clothing.

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I was reading an interesting old paper the other day about Q-fever in cats. Q-fever is a zoonotic disease caused by Coxiella burnetii. It is most commonly associated with contact with sheep, cattle and to a lesser extent goats, around the time they give birth. This bacterium is highly infectious - it only takes a small number of bacteria to cause disease. (That's one of the reasons it's classified as an important bioterrorism agent).

While most of the focus in on ruminants, there have also been many reports of Q-fever associated with cats, also mainly through contact with these animals around the time they give birth.  Cats may be the most important Q-fever reservoir in urban areas.

The study I was reading, a 1988 article from the journal Chest, describes a Q-fever outbreak in a town in Nova Scotia. Thirty-three people were infected in the town of Baddeck (population 900, meaning 2.8% of the population was affected). Forty-two percent of infected individuals lived in four side-by-side buildings. Investigation revealed that most infected people had contact with a cat that have given birth to stillborn kittens (stillbirths are common in cats infected with Coxiella). The cat lived in one of the four buildings and regularly visited neighbouring buildings.

This is just one of many reports of Q-fever associated with cats. Almost all involve direct contact or being in the vicinity of cats around the time of birth. Since this bacterium is so infectious, and can even be spread through the air through aerosols (e.g.dust, tiny droplets of fluid), direct contact (e.g actually touching the cat) is not required for infection to occur.

That being said, cat-associated Q-fever is probably still pretty uncommon, but Q-fever can be a very serious disease. Since transmission mostly involves cats at the time of birthing, a few basic measures should be able to greatly reduce the risks:

• Avoid contact with cats that are giving birth or who have done so recently.
• Avoid contact with newborn kittens and areas contaminated during the birthing process.
• If your cat is going to give birth, try to have it do so in a well-ventilated area away from areas where people spend time and away from areas where food is prepared.
• If contact with the mother cat, kittens or areas/items contamination with birth fluids is likely to occur, gloves should be worn. Hands should be washed after gloves are removed.
• If a cat gives birth inside, the area should be thoroughly cleaned and disinfected afterwards. Gloves should be worn for this.
• The risks are probably higher with stray cats (who are more likely to be infected), so extra care should be taken to avoid contact with stray cats around the time of birth.

More information about Q-fever can be found in the Worms & Germs archives.

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I recently wrote about Mycobacterium bovis, the cause of bovine TB and a pathogen that can be transmitted to people and rarely to pets. A reader made the following comment:

"Having come across your very interesting blog, I was questioning/wondering whether your statement regarding Mycobacterium bovis, "whose main natural reservoir is cattle", is in fact actually so any longer; if ever. . In the UK all cattle herds were once declared clear of this disease by testing and culling and the gassing of badgers, until the government protected the badger over here to appease animal rights activists and gain a few extra votes.  Now it is rife again. These people somehow believe badgers have 'rights' to life above farmers' cattle.

I often wonder if the 'bovine' association is simply because the bacterium was first isolated in cattle as they were obviously captive and there to be investigated. Could it just as easily have been called Mycobacterium meles?  As I understand it, Mycobacterium tuberculosis came first and originated in humans and then developed as Mycobacterium bovis in animals"

Good question. Just because a disease is named after a particular species does not mean that it's the main source or original source of the pathogen responsible. Cowpox virus is a good example - cows aren't actually the reservoir of this virus, rodents are. However, because cows are more closely observed or monitored than rats, it was originally associated with cows and thus named cowpox.

We are more likely to detect diseases in humans first, followed by domestic animals, followed by wildlife. Severe acute respiratory syndrome (SARS) is a good example of this. This disease was first found in people. It was then linked to civets and raccoon dogs. However, civets and raccoon dogs aren't the true reservoirs, nor where the disease originated. It appears that the reservoir is in fact bats. Bats are a lot harder to investigate than captive animals, so even though they are now the presumed reservoir, it took a while to figure that out.

Back to Mycobacterium bovis... It's impossible to say for certain where it originated. Since it is thought to have evolved from Mycobacterium tuberculosis, the reservoir of which is people, it makes sense that the evolution of M. bovis would involve a domestic animal species instead of a wildlife species.  Cattle have much closer contact with people than do wildlife such as badgers, opossums and deer. So, since M. bovis has historically been most strongly associated with cattle, and cattle live in close contact with humans, I woudn't be surprised if they are the true orgin in this case. However, since M. bovis can infect a very wide range of species, we can never really know.

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A paper in the Journal of Clinical Microbiology back in 2000 described a case of Pasteurella multocida meningitis in a one-month-old baby that was linked to a pet cat. Pasteurella multocida is a bacterium that can be commonly found in the mouth of healthy dogs and cats - 90% or more of healthy cats may have it in their mouth. The organism can cause infection in humans.  These cases are usually associated with close contact with animals, such as bites, scratches and licking wounds. In this case, there was reportedly little contact between the baby and the cat, yet the same P. multocida strain was found in both. The cat was healthy and the bacterium was found in its mouth. There was no clear route of transmission (like a bite or a scratch), however unidentified contact with the cat or (more likely) indirect transmission of the bacterium from the cat to the baby by another person are possible.

This is a good example of the unpredictable nature of zoonotic infections. There was no reported underlying disease that made this baby more susceptible to infection. It's just that being very young (or very old, or immunocompromised) means you're more likely to develop infections from the myriad bacteria that are present all around us. While this infection might not have been preventable, we need to think about good routine precautions involving contact of pets with babies.

• Keep them apart (but not completely). Pets should not be allowed to lick or have other close contact with a young baby. That being said, household pets need to be around the baby to learn to interact with the child safely, and recognize the baby as a member of the family, but supervision is needed and direct contact should be avoided.
• Good hygiene should be used around pets and babies (individually and together). Hands are the main source of disease transmission and regular hand washing is a great infection control tool.

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Another surge in the number of cases of Q fever in people in the Netherlands has been reported.  Prior to 2007, the average number of cases of Q fever per year in the country was only 15.  In 2007 there were 192 cases, and last year there were 958 cases, making this the largest community outbreak of Q fever ever reported.  At the beginning of May 2009, another jump in the number of cases - over 200 - was reported by the dutch newspaper de Volkskrant.

Q fever is caused by a highly infectious organism called Coxiella burnetii.  The organism can be carried by many different animals, but particular sheep and goats, and sometimes cattle.  Most of the time it does not cause a problem in these species, but it has been linked to abortions and abortion storms (i.e. when many animals in the herd abort in a short period of time).  It can be shed in manure, urine and milk, but the largest numbers of organisms are found in birth fluids and tissues (e.g. aborted fetuses, placentae).  When the tissues and fluid dry out, the organism can be stirred up into the air over short distances in dust.  Humans are highly susceptible to C. burnetii, and inhaling even a single organism can cause infection.  Most of the time people who get sick have signs very similar to the flu, but severe pneumonia and liver disease can develop in a small number of cases.

A definitive link between sheep and goats and the Q fever outbreak in people in the Netherlands has not yet been established, but it is highly suspected that many of the cases are associated with infected goats (and some sheep).  In the last two years numerous outbreaks of Q fever have been reported on dairy goat farms and one dairy sheep farm in the Netherlands.  This has lead to a cooperative arrangement between the Dutch agricultural ministry and the Dutch public health ministry - these two goverment branches have come together to help cover the costs of vaccinating sheep and goat herds in the country, in order to help stem the tide of disease and ultimately prevent more human cases.  This is a great example of the "one medicine" concept, whereby groups on both the human health and agricultural/animal health sides are working together on this problem.

Manditory vacciation is now required for sheep and goats on larger farms in the hardest-hit areas, as well as any farms reporting any cases of Q fever since 2005, and any sheep or goats that have a "public function" (e.g. petting zoo animals or occupational therapy farms).  It is very important that this last group is included under the manditory vaccination, as these animals have a large amount of contact with people.  Steps have also been taken to improve hygiene, restrict spreading manure from sheep and goats, restrict visitors to infected farms, and to make abortion storms on sheep and goat farms reportable, so they can be investigated for Q fever.  It will be interesting to see how effective these measures are at controling the outbreak in 2009.

More information on Q fever can be found in our archives.

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ProMed recently reported about an outbreak of canine brucellosis at a "puppy farm" in Ireland. Farm is definitely the appropriate word in this case, since this operation had about 700 breeding females. The picture on the right is not from this farm, but I imagine it's a similar operation. Beyond the concerns about humane management of dogs under these conditions, such a large operation creates perfect conditions for various infectious diseases.

"The farm's owner has refused to sign an undertaking not to move the dogs off-site before an official inspection can take place to investigate the extent of the [brucellosis outbreak]."

Lack of cooperation makes any disease investigation much more difficult. It's not surprising this person doesn't want to cooperate, given the type of operation he's running.

"Someone from the farm told the Irish Times that the 2 animal welfare agencies were involved in acts of "intimidation" against the establishment."

I suspect that "intimidation" in this case means the agencies were doing their job, because I can't see how there wouldn't be significant welfare problems at a farm of this type and size.

"'We got accurate information on Friday [2 May 2009] that this man was intending moving and selling these dogs and we acted on it,' according to Jimmy Cahill, chief executive of the DSPCA [Dublin SPCA]. 'The guards  were very helpful but the owners refused to let us see the dogs or any of the carcasses.' "

The reference to "carcasses" implies that deaths have occurred. Death from B. canis in dogs is very rare but it is possible. However, a poorly managed operation with hundreds of dogs is bound to have multiple issues that could cause deaths.

Canine brucellosis is caused by the bacterium Brucella canis. This main problem with this bacterium in dogs is reproductive disease, including abortion and infertility (in both males and females). Discospondylitis (inflammation of the discs between vertebrae in the back) can also develop.

Brucella canis is a zoonotic organism. Human infections are rarely reported but it is possible that some go undiagnosed. Brucella canis can be transmitted from dogs to people through contact with body fluids from infected dogs, including urine and vaginal fluids.  The risk of transmission is likely highest when handling animals during breeding or birthing. While the bacterium can be shed in nasal secretions and saliva, levels are low in these fluids and the risks are probably correspondingly low.

One problem with preventing B.canis transmission is that infected dogs do not necessarily show any signs of disease. In people, B. canis infection can cause flu-like disease, loss of appetite, weakness, joint and back pain, vomiting and diarrhea and various other symptoms.

To control the outbreak on this "farm," quarantine and repeated testing of all dogs is needed, and positive animals must be removed from breeding. Given the information provided above, it's pretty unlikely this will happen voluntarily. I suspect this person would likely either just get rid of these dogs and get more poor-quality breeding animals, or try to continue breeding these dogs and hope people get sick of looking into his operation.

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The World Health Organization (WHO) has provided the latest update about H1N1 influenza numbers internationally. (People are still often calling this "swine flu", but it has yet to be found in pigs and is clearly being transmitted human-human now, therefore some have recommended it be called "Mexican flu" or "North American flu" instead.  This also decreases the negative associations with pork products, which are totally unfounded because the virus is NOT a food safety concern). Regardless of the name, this pathogen continues to move across the planet. The WHO is reporting 148 laboratory confirmed cases. Ninety-one have been confirmed in the US with 26 confirmed in Mexico.

It's important to remember that confirmed cases are very much the "tip of the iceberg". It's likely that there are thousands of cases in Mexico, despite only 26 having been confirmed by laboratory testing. For a case to make this list, the sick person has to go to a doctor AND samples have to be collected for testing AND the testing has to be appropriate for identification of swine flu versus other types of influenza. Areas with more diagnostic testing capacity and public health infrastructure (like some places in the US) will end up reporting more cases, even if they actually have fewer sick people. So, we shouldn't become complacent when reading about relatively small numbers of confirmed cases, and we must take care when comparing regional rates.

Confirmed cases have also been reported in Austria (1), Canada (13), Germany (3), Israel (2), New Zealand (3), Spain (4) and the United Kingdom (5). Deaths have only been reported in Mexico and the US, with the single (to date) US death being a child that was visiting from Mexico.

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GoogleMaps has an interactive swine flu map that is quite interesting. The map indicates where cases of the disease have been diagnosed or are suspected, and it's updated frequently.  Clicking on a marker gives you more information about what is happening in that particular location. Many of the pink "suspected" markers will probably turn out to be negative, but I fear the map's going to get a lot more crowded over the next couple of days. The picture below is a captured image of the map, but click here for the live interactive version.

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The European Union's Health Commissioner has recommended that Europeans avoid all non-essential travel to the US and Mexico (Canada's apparently under the radar so far) as a measure to contain the spread of the emerging swine influenza virus. This has been met with some disdain by US officials, who emphasize the small number of cases (so far) in the US, and the much, much larger numbers of people that die in various countries every year from classical human influenza.

It's hard to say what type of restrictions are appropriate at this point in the outbreak. In general, it's better to be prudent and excessive (within limits) when dealing with a developing problem. The lack of information about the true scope of the problem, and the delays from transmission to definitive diagnosis of new cases, complicate assessments about whether the problem is truly contained, or containable.

Swine flu was most recently confirmed in Spain, and it has probably reached many different countries. It is also suspected in a group of students in New Zealand that recently visited Mexico.  Considering the massive volume of travel between North America and much of the world, and the wide geographic range of cases in North America, it's hard to envision keeping this localized.

The fact that this outbreak is going to be difficult to contain, however, should not be taken as an excuse to not try to contain it. Even if this virus spreads to many different countries, good infection control and surveillance measures can help limit the impact of the disease.

Photo: Chichen Itza, one of the major tourist attractions on the Yucutan Peninsula in Mexico (credit M. Anderson)

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In response to increasing numbers of confirmed or suspected cases of swine flu in the US, plus a still relatively unknown number of cases and at least 81 deaths in Mexico, the US government has declared a public health emergency.

This H1N1 swine influenza virus has many of the hallmarks of a virus with pandemic potential. It is of animal origin but has a unique combination of gene sequences that has not been found previously in swine or human influenza strains. People don't have pre-existing antibodies because they have not been exposed to it before, which leads to the chance for widespread disease. A big concern is that it seems to spread at least somewhat efficiently between people (unlike the H5N1 avian flu virus which is not efficiently transmitted between people). Fortunately, while it can cause death, this swine flu virus does not seem to be as deadly as avian flu, which kills approximately 50% of the people it infects. Therefore, while swine flu appears to be much more transmissible, it's probably not as fatal. (However, the large number of reported deaths in Mexico and early stage of the outbreak at this point means we need to be cautious making such statements).

It is clear that this swine flu strain is spreading in the US. It's been found in multiple US states and it is probably going to be found throughout the country.  Mild cases have already been confirmed in Canada, and there are suspected cases in other countries. The number of cases in different regions and the amount of international travel makes containment of a reasonably-transmissible virus very difficult.

Some tips to reduce the risk of catching (or spreading) swine flu:

• Wash your hands regularly, particularly after contact with other people or common-contact sites (e.g. public door handles, public transit).
• If you are sick, STAY AT HOME. The era of "sucking it up" and going to work when you are sick should be over. All you're doing is putting others at risk.

More information about swine influenza can be found on the CDC's swine influenza website.

Image from http://www.nydailynews.com

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Plague has been diagnosed in a dead rabbit found on a private residence in New Mexico. Plague, also known as the black death, is a highly fatal disease of humans and many animals caused by the bacterium Yersina pestis. While often considered a disease of mainly historical interest - having killed a large percentage of people on the planet during a few pandemics over the centuries - plague is actually still alive and well in some regions. In North America, most cases occur in New Mexico, Arizona, Colorado and California.

Yersinia pestis primarily lives in wild rodents and is transmitted by fleas. Many different animal species, including cats, dogs, rabbits and people, can be infected if bitten by a flea from an infected rodent (hence the historical association of the disease with rats). Predatory species (like dogs and cats) can also become infected by eating infected animals. Dogs are relatively resistant to plague and usually only develop mild disease, while cats and rabbits are as susceptible as people, and can develop bubonic, septicemic or pneumonic plague. Transmission of plague from pets to people can occur, and most often involves cats. People can become infected by close contact with sick pets, or being bitten by a flea from such a pet.

Preventing plague in animals involves flea control and reducing exposure to infected wildlife. In areas where plague is active, all pets should be on a flea control program. Cats should be kept indoors to reduce the risk of exposure (e.g. keeps them from hunting infected rodents). Dogs and cats should not be allowed to have contact with dead animals of any kind. Measures to reduce rodent infestations in and around the house are also important.

More information on plague is available in the Worms & Germs archives.

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People that work with animals are at increased risk for certain infectious diseases. That's pretty clear. Pet shop employees fit into this group as well, and they may be at particular risk for specific diseases because of their close contact with young animals, birds, rodents and reptiles. A suspected case of psittacosis in a Toronto pet shop worker is an example of this.

A bird in the pet store where this person worked supposedly died of avian chlamydiosis in mid-March (although the initial test results have been called into question). Avian chlamydiosis is caused by the bacterium Chlamydophila psittaci. This organism is relatively common in psttacine birds (parrot family), especially in breeding colonies, but can also be found in other types of birds. It can cause serious disease in birds, but it is also commonly carried by healthy birds. People can become infected from breathing in the bacterium, often from aersolized dust containing dried bird droppings. The disease in people is called psittacosis. The pet store worker developed signs that could be consistent with psittacosis: cough, lethargy and difficulty breathing.  However, these signs are still fairly non-specific and could also be caused by numerous other respiratory pathogens.  Test results are still pending.

People that have close contact with pet birds, especially psittacines, need to know that they may be at increased risk of psittacosis. They also need to ensure that their physicians know about their increased risk. This is important because early signs of psittacosis are very vague, such as fever and cough. Psittacosis would presumably not be high on the doctor's list of possible diagnoses for the average person coming in with fever and a cough. If the doctor knows a person has contact with birds, hopefully psittacosis would be considered earlier so prompt diagnosis and appropriate treatment can be given. This disease is readily treatable if diagnosed early, so awareness of the possibility on the part of the patient and physician are important.

This report also demonstrates why determining a final diagnosis for sick or dead pets is critical. While the diagnosis may not help the animal (especially if it's already dead), it may play an important role in protecting the health of people or other animals. If the bird in this case was not tested, it's hard to say how long it would have taken for psittacoiss to be considered in the case of the pet store worker.

More information about psittacosis can be found in a document from the National Association of State Public Health Veterinarians. More information about good management practices to reduce the risk of disease transmission from birds can be found in the information sheets on pet birds on the Worms & Germs Resources page.

Image from: http://www.cbc.ca/health/story/2009/04/01/parrot-fever.html

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A study published recently in the Journal of Hospital Infection (Lefebvre & Weese, 2009) looked at contamination of the haircoat of animals used in hospital visitation programs. In the study, Dr. Lefebvre petted animals that were going into a hospital and we cultured her hands.  Then when the dogs finished their visits she petting them again and we re-cultured her hands.  We tested for MRSA and Clostridium difficile, two important causes of hospital-associated infections. The goal was to see if the dogs' coats could become contaminated, presumably by patients' hands, during regular visits. The dogs' paws were also tested before and after to see what they picked up walking around the hospital.

After being in the hospital, one dog (4%) was found to have C. difficile on its feet. The strain that was recovered (ribottype 027/NAP1) is a strain of great concern, being it has caused outbreaks of illness internationally. The fact that there was C. difficile on the dog's paws, which was presumably picked up from the floor in the hospital, isn't exactly surprising. It shows that contact with dogs' feet (e.g. shaking a paw) could be a source of exposure to people in hospitals, and at home, and that dogs could be exposed to C. difficile after hospital visits by licking their paws. We previously demonstrated in another study that visitation dogs are at high risk for picking up C. difficile during visits.

The more important aspect of the study was what ended up on Dr. Lefebvre's hands after petting the dogs - a very common type of contact with dogs in hospitals and at home. She picked up MRSA from the coat of one dog (4% of dogs overall) after it had been in the hospital. The dog was not an MRSA carrier, and it did not have contact with anyone known to be carrying MRSA during its visit. Presumably, there was someone in the hospital that was an unknown carrier. If MRSA was on the person's hands, they could have transfered the MRSA to the dog's coat. The important part is that this MRSA was then able to spread to someone else's hands (Dr. Lefebvre's, in this case). This is a potential route of transmission of MRSA to patients during hospital visitations, and to other people these dogs might encounter outside of hospitals. The same thing could presumably happen with other infectious agents, including bugs like norovirus and influenza. These can't infect dogs, but dogs could potentially be short-term vectors of these viruses and spread them around a hospital.

The good thing about all this is that some basic guidelines can greatly reduce the risk of transmission:

• Patients should wash their hands  or use an alcohol-based hand sanitizer before  (to reduce the risk of depositing something on the pet's coat) and after (to reduce the risk of picking something up from the pet's coat) touching a pet.
• Pets should be kept off beds unless a disposal/washable barrier (e.g. drape, towel) is kept between the pet and the bed sheets, to prevent dirty feet from infecting the patient's living space/clothes/sheets.
• People should not "shake-a-paw" with pets in hospitals.

All these precautions can be taken without compromising the benefits of hospital pet visitations. More details about guidelines for hospital visitation aniamls can be found in an earlier post. More information about Clostridium difficile and MRSA can be found on the Worms & Germs Resources page.

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The following is a post by guest-blogger, Dr. David Waltner-Toews.

For North American veterinarians, the term “companion animals” covers a wide territory, from dogs, cats, and caged birds, to a variety of rodent and porcine escapees from barnyards and burrows. But when does a companion become something else? In my work with Veterinarians without Borders/ Vétérinaires sans Frontières – Canada, I find that I sometimes have to change my ideas of what companion animals are.

We have all heard about bird flu, and the fear that it might become a global pandemic. We know that wild water birds are the main reservoir for all the different kinds of influenza viruses that emerge every year from Southeast Asia and circle the world. The viruses are unstable, and historically haven’t caused many problems in birds. The disease in people can be serious, especially in older people, but large scale vaccination programs have helped. The big concern is that a new variation of the virus has evolved and has spilled from water birds into domestic poultry. A virus that not only kills birds, but also kills a high percentage of people – and other animals such as cats. Fortunately, it is difficult to contract – you pretty much have to be the one killing and cleaning the bird.

To some people, the way to stop a global pandemic is easy. If you suspect bird flu on a premise, kill all the birds and disinfect the area. Easy, isn’t it? They are, after all, “just chickens”. Or are they?

When my wife and I recently visited a part of the island of Java, Indonesia, where this new virus is thought to be endemic, that is, a lot of birds are carrying it, I already knew it was more complicated than just killing chickens. Often, poor people will “salvage” sick, dying or even already-dead birds by cooking them up and eating them before the authorities discover them. If you are hungry, it seems such a waste not to.  As a result of such situations, about 120 people in Indonesia have died of bird flu since 2003.

But, we discovered, poverty is not the only “complication”. We held a town hall meeting in one village, in the middle of this endemic area, to explore how they were coping with the disease. They told us that they didn’t have any bird flu. Certainly, sometimes, they had some sick birds, which they threw into the river, but no bird flu. They attributed their disease-free status to the fact that they fed their birds a warm porridge made from snails and papaya leaves.

After our town hall meeting, we trundled through the rain to one of the nearby chicken-owners.  When we entered the well-kept concrete-walled yard, a young boy proudly showed us his pet pigeon. His father, however, did him one better. It turns out that this family raised singing roosters, so-called Ayam Pelung, beautiful birds, about a metre high. I knew that wild jungle fowl had first been domesticated in Southeast Asia tens of thousands of years ago as fighting birds, now referred to in Indonesia as Ayam Bangkok.

I had heard about the singing birds, and had seen them in their cages at a competition at the veterinary college in Yogyakarta when I worked there in the mid 1980s, but this was my first close-up view. The men who owned them proudly crouched next to them for pictures. Periodically, one of the roosters would stand still and give a long, drawn out, low, throaty call, an avian version of some sultry lounge singer. These birds, if they win competitions throughout the country and region, apparently bring in up to 500 to 1000 U.S. dollars each. In a country where the average annual income is between $3000 and $4000, a few birds can represent a huge investment. Are these birds companion animals? Are they friends, workers, threats… or just chickens?

When is a dog or a cat or a bird more than a companion? When they sing? Race? Fight? When they are worth lots of money? In Thailand, where fighting cocks are common, and are valuable, the authorities have issued “vaccination passports”, with pictures of the roosters, indicating vaccination with a reputable influenza vaccine. When, in trying to control a disease, do we cross the line from “culling” economically important “units” to killing companions? When do we hand out passports?

If you had an amazing purebred dog worth tens of thousands of dollars, and the public health authorities threatened to kill it if it was found to be harbouring some virus which might or might not make you sick, what would you do? What if that dog was not only your companion, but your retirement investment?

Suddenly controlling a bird flu pandemic is a lot more complicated than killing “just chickens”. Welcome to the real world.

David Waltner-Toews is the founding President of Veterinarians without Borders/ Vétérinaires sans Frontières – Canada (www.vwb-vsf.ca) and a Professor in the Department of Population Medicine at the Ontario Veterinary College.

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The spleen is an important part of the immune system. It is especially important for fighting off certain types of infections. People who have had their spleen removed or whose spleen is not working properly are therefore at greater risk of some infectious diseases. The risk of infection is highest in the first few years after the spleen is removed or stops functioning, but the risk remains increased for life. In general, people who are immunocompromised (i.e. have a weakened immune system (including lack of a working spleen)) can get sick from microorganisms that would not usually cause illness in other people, and bugs that would only make most people mildly ill can cause severe infections in immunocompromised individuals.  This is a particular problem in children.  Kids that have their spleen removed are often treated with antibiotics for a few years to help prevent infections.

Infection with Streptococcus pneumoniae and Haemophilus influenzae, which are both common  pathogens of humans, are two of the major concerns in people without a functioning spleen.  The most commonly discussed zoonotic disease threats in these individuals are the bacterium Capnocytophaga canimorsus and Salmonella.  Capnocytophaga lives in the mouth of a large percentage of healthy dogs.  Infection in immunocompromised people typically occurs as the result of a bite, but is very rare in other people.  There is no indication to test dogs for Capnycytophaga, because it is difficult to identify and we do not know how confident we can be about a negative result (e.g. it may be in the dog's mouth even though it doesn't grow from a sample in the lab).

Here's some general advice for individuals who don't have a working spleen:

• Talk to your physician or an infectious disease specialist about the risks associated with animal contact (including pets).
• In general, you do not need to give up your pets. The risk of infection may be increased, but the risks can be minimized in most situations, and the risks are often outweighed by the beneficial aspects of pet ownership.
• Be wary of any possible exposure to an infectious disease, and be diligent about infection control precautions. If you are bitten by an animal (of any kind), see a doctor as soon as possible.
• Make sure your pets do not touch any open wounds you may have.  In particular, do not let a dog lick skin that is damaged in any way.  Since Capnycytophaga is commonly carried in the mouths of healthy dogs, licking in general should be discouraged.
• Don't feed your pet raw meat or raw treats, because this increases the risk exposure to Salmonella from your pet's stool.
• Be very careful when handling stool to avoid contaminating yourself or other objects/surfaces. If you have a cat, ideally its litterbox(es) should be changed by someone else.
• Always wash your hands well (and frequently) after contact with pets and pet foods, including dry commercial pet food (kibble).

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Methicillin-resistant Staphylococcus pseudintermedius (MRSP, sometimes misidentified as methicillin-resistant S. intermedius (MRSI)) is an increasing problem in dogs and cats. This highly drug-resistant bacterium is a particularly problem in skin and ear infections, and the number of infected animals appears to be increasing significantly. A related bug, methicillin-resistant S. aureus (MRSA) has been a major problem in people for decades, and MRSA is now being found with increasing frequency in animals as well. Sometimes people get confused when they are dealing with methicillin-resistant staph, and it's important to realize some of the differences between these two related bugs:

• MRSA is a huge problem in people and can be transmitted between animals and people. The role of animals in human disease is unclear, but there is concern that people can develop infections due to contact with infected or colonized animals.
• MRSP is rarely identified as a cause of infection in people. Transmission of MRSP between animals and people has been reported. However, this is much less concerning than with MRSA because people are much less likely to carry, transmit or develop infection from MRSP than MRSA.
• The recommendations that have been made for management of animals with MRSA largely involve improving general household infection control practices. These guidelines are only based on expert opinion (i.e. there are no studies (yet) to back them up), but they are reasonable and practical.
• Even less information is available regarding MRSP, mostly because it's not considered a major human health issue. That being said, you don't want to get a multidrug-resistant bacterial infection, even if it's uncommon. Therefore measures to reduce the risk of transmission of MRSP from pets to people is should still be considered.
• Strict isolation of infected pets is probably excessive. General infection control practices (e.g. handwashing after contact with the animal, avoiding contact with the infected site, limiting contact overall) are probably adequate, especially in households with no high-risk people (e.g. people with weakened immune systems, infants, elderly individuals).

More information on both MRSP and MRSA can be found on the Worms&Germs Resources page.

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In contrast to dogs, urinary tract infections (UTIs) are uncommon in cats, although urinary tract disease is very common.  The vast, vast majority of cats with signs of feline lower urinary tract disease (FLUTD) (e.g. straining to urinate, frequent urination, bloody urine) do not have an infection.  However, many cats with urinary tract disease are treated -  unnecessarily -  with antibiotics. That's a problem, for several reasons:

• Antibiotics are not effective if there is no infection, and treating with antibiotics delays addressing the animal's real problem.
• Use of antibiotics in these cases unnecessarily increases the risk of antibiotic resistance emerging. Even if there is no infection in the bladder, resistant bacteria may emerge elsewhere in the body. Antibiotics don't just go where we think the infection might be - they also go to areas where there are always bacteria, like the intestinal tract, and resistance can emerge there.
• Adverse reactions to antibiotics can occur. Vomiting and diarrhea are most common.
• Proper diagnostic testing should be performed in every cat with urinary tract disease. This includes evaluation of a urine sample under a microscope to look for signs of infection (such as white blood cells) and a urine culture.

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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.

More information about the care of bites can be found in our bites archives and on the Cat Bites information sheet on the  Worms&Germs Resources page.

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Plague (aka the "black death") is a fascinating disease. It is one of the most important diseases in human history because it had a devastating impact of the human population during various outbreaks. Many people may not realize it, but plague is not just a historical problem - it is still alive and well in some areas of the world. Plague is caused by the bacterium Yersinia pestis, which tends to circulate in rodent populations and can be spread by fleas. In North America, plague is most common in some regions of the southwestern US, particularly New Mexico, Arizona and Colorado. We're heading into the high-risk season for plague in those areas: March to October.

Plague can infect domestic pets, and pets can be a source of human infection.  Cats are quite susceptible to plague, whereas dogs are quite resistant.  Cats can transmit plague to people.  Pneumonic plague (infection of the lungs with Y. pestis, not to be confused with bubonic plague which is primarily infection of the lymph nodes with Y. pestis (see picture left)) in cats is of particular concern, because in this form the bacterium can be spread through the air over short distances.

Prairie dogs (which some people keep as pets) are also very susceptible to plague.

A paper in Clinical Infectious Diseases a few years ago (Gage et al, 2000) described 23 cat-associated cases of plague in people, five of which were fatal. People were infected by face-to-face contact, bites, scratches or simply caring for an infected cat. Most affected people were cat owners, but some were veterinary clinic personnel.  Plague is treatable with antibiotics, but the disease can progress rapidly, so it's important to determine the diagnosis and start treatment as soon as possible.

Here are some things to consider if you live in an area where plague exists:

• Keep pets indoors as much as possible to help prevent exposure to infected wildlife.
• Use routine flea control measures as directed by your veterinarian.
• Consider any cat that develops a fever of unknown origin or enlarged lymph nodes a plague suspect.
• Don't let cats and dogs hunt wild rodents, and don't let them have access to rodent burrows.
• If your pet has been diagnosed with plague, you need to seek medical attention promptly in case you have been exposed. If a person in the household is diagnosed with plague, pets should be investigated as possible sources and should be treated prophylactically in case they have been exposed.

Lower photo: Bubo in the leg of a person infected with bubonic plague (source: Centers for Disease Control and Prevention)

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I came across an interesting (and somewhat bizarre) paper in the journal The Lancet from 1988. It described a case of listeriosis in a baby. Listeriosis is caused by the bacterium Listeria monocytogenes. Human infections are usually acquired from eating contaminated food. I made some comments about the risk of listeriosis to household pets in an earlier post during the recent  foodborne outbreak of listeriosis in Canada that was associated with contaminated meat

The paper from 1988 puts a "new spin" on potential sources of infection for pets.

The baby described in the report was not breastfed for the first three days of life because her mother had some post-delivery complications. The surplus milk that was collected over those three days was reportedly fed to a litter of Doberman puppies. All three puppies in the litter became sick the day after the child began showing signs of illness. Listeriosis was diagnosed in both the baby and the puppies. Listeria monocytogenes was cultured from the mother's milk. Apparently the baby and the puppies were all infected by drinking the mother's milk. The baby, and two of the three puppies, survived.

Certainly, human-associated listeriosis in pets is extremely rare, and (presumably) so is feeding puppies human milk. This case just shows how infectious diseases can do strange things, and that diseases can move between people and animals in both directions. It also highlights that knowing the health status of both animals and people is important for physicians and veterinarians to make informed decisions about diagnosis and treatment of some diseases.

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One of my favourite stories about surgeons comes from a book by Irwin W. Sherman called "The Power of Plagues." In the pre-anesthesia and pre-antibiotic era, speed was considered the sign of a good surgeon. One surgeon, Robert Liston, was particularly renowned for his speed. However, speed sometimes lead to problems. In one surgery, he amputated a leg in 2.5 minutes, but the patient died of infection after surgery (a common event those days). During surgery, he accidentally amputated the finger of his assistant as well, who also subsequently died of infection. To top it off, he slashed the coattails of a surgeon who was watching, who "died of fright" thinking his organs had been slashed too. He's the only surgeon on record with a 300% mortality rate for a surgery.

These days, surgery is a lot more humane and safe. However, problems like surgical site infections still occur. They occur following a much smaller percentage of surgeries than they used to, but they can still be very serious.  Nowadays, more of these infections are being caused by multidrug resistant bacteria, which can affect and be transmitted between both animals and people. It's been stated that the time of maximal influence on surgical site infections beings and ends in the operating room (e.g. the most critical time for preventing infection is during the surgery itself).  However, there are things that can be done at home to help reduce the risk of infection.

• Antibiotics are usually NOT required after surgery, depending on what procedure was performed. But, if antibiotics are prescribed by your veterinarian, make sure you give the full course and follow all instructions carefully.
• Keep your pet from licking the surgery site. Trauma from licking and chewing, and bacteria from the mouth can help start an infection. If your pet is licking or chewing its surgery site, consult with your vet about ways to stop this.
• Keep an eye on the surgery site. If you see signs of infection such as excess heat, pain, redness, swelling or discharge from the site, talk to your vet as soon as possible.
• Don't touch the surgery site. You could contaminate the site with bacteria from your skin that could start an infection. Also, if an infection is present, bacteria could spread to you.  If you must touch the surgical site (e.g. if you need to change the bandage over it, or your veterinarian has instructed you to clean the site), you should wear disposable gloves.

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If your veterinarian suspects your pet may have ringworm, there are several different ways he or she may test for the causative fungus (a dermatophyte) on your animal's fur and skin.  Some of these techniques are more useful than others in different situations.

• Wood's lamp:  A Wood's lamp is simply a special ultraviolet light.  Approximately half of all Microsporum canis strains (the most common species of dermatophyte that causes ringworm in cats and dogs) will fluoresce blue-green under such a light. This type of testing is obviously very easy to perform.  However, other debris in an animal’s hair coat may fluoresce as well, and other species of fungus that cause ringworm do not fluoresce, so this test is not useful by itself in most cases.
• Microscopy: Sometimes ringworm fungus can be seen on hair shafts from an infected pet when examined under a microscope.  However, it is easy to confuse other debris and structures for dermatophytes.  Also, not every hair on an infected animal will carry the fungus, so it's possible to miss the infected hairs altogether with this test.
• Fungal culture: The best way to diagnose ringworm is to culture the fungus from the infected individual (person or animal). In animals, one of the best ways to collect a sample for culture is to comb over all the fur and skin with a new toothbrush, and then try to grow dermatophytes from the toothbrush. This allows the fur from all over the animal to tested, rather than just one little clump of fur plucked from one area.  It can also make it easier to get a sample from the face and paws of cats, which is where these animals often carry the fungus.  Although fungal culture is the best way to diagnose ringworm, remember that fungal culture takes much longer than bacterial culture – instead of days, it may take up to three weeks to grow some dermatophytes.

It's also important to remember that dogs, and more often cats, may carry dermatophytes on their fur even when they look healthy.  A positive fungal culture from an animal with skin disease, particularly a cat, does not necessarily rule out other diagnoses, so your veterinarian may still recommend other tests as well.  However, any animal with ringworm should be treated to prevent spreading the infection to other animals and people.

More information about ringworm is now available on the Worms&Germs Resources page, and in our archives.
 

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I've had this question a lot lately. Methicillin-resistant Staphylococcus pseudintermedius (MRSP), which is sometimes misidentified as methicillin-resistant S. intermedius (MRSI), is an important and increasing cause of infections in dogs and cats. After an animal has had an MRSP/MRSI infection, a question people often ask is how long they will carry the bacterium?

MRSP can be carried in the nose, intestinal tract or on the skin of a small percentage of normal animals. The implications of this are not clear, but it is reasonable to assume that carriers are more likely to develop infections in certain situations (e.g. if they sustain a wound or need to have surgery), and can transmit it to other animals (and possibly people, but that's much less of a concern with MRSP than with MRSA).

Back to the question... To be perfectly honest, we really don't know. However, I think it's reasonable to assume that some animals could carry MRSP for a long period of time - certainly weeks or months, maybe even years. Staphylococcu pseudintermedius is a common bacterium in healthy dogs and cats, and has basically evolved to survive on these animals. The methicillin-resistant versions are likely no different in this respect, so it's reasonable to assume that some animals could be long-term carriers. This makes controlling MRSP more difficult.  In contrast, MRSA appears to be only transiently carried by dogs and cats, probably because it is better adapted to living on humans than pets.

What you should do in the meantime if your pet has MRSP:

• Treat any infection as per your vet's instructions.
• Always complete the full treatment course.
• Wash your hands after contact with your pet, healthy or not.

More information about different types of staph bacteria can be found in the previous Worms&Germs post entitled Methicillin-Resistant Staph - What's In A Name?

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Mumps is a common (and highly infectious) viral disease in people, particularly children.  Typically it causes flu-like symptoms (fever, headache, aches and sore muscles) as well as painful swelling of the parotid salivary glands.  These glands are located within the cheeks near the angle of the jaw, just below the ear.   Illness usually lasts for about ten days, but in young adults the infection can cause serious complications, including meningitis and deafness.  Because the disease is so infectious, it is recommended that anyone with the mumps be isolated for nine days - that means no going to work, school, the store or anywhere else!

Dogs may actually be able to get mumps too, but it's very uncommon.  Dogs living with recently affected children have been reported to develop similar signs of illness to humans, including fever, not wanting to eat and swollen parotid salivary glands, and antibodies to mumps virus have been found in some dogs.  It's also been shown that the virus grows well in canine cell cultures in the laboratory.  However, there are no experimental trials that have definitively demonstrated transmission of mumps to dogs.

Because mumps is caused by a virus, antibiotics are not useful for treating the infection.  In dogs suspected of being infected, specific treatment is usually not needed - just some TLC and most dogs recover within 5-10 days.  There are no reports of people getting mumps from a dog - this is primarily a disease of humans.

People, but not dogs, can be vaccinated for mumps.  The vaccine is part of the MMR (measeles, mumps and rubella) vaccine, which many people receive when they are children.  For more information about this disease and vaccination, see the website of the Ontario Ministry of Health and Long-Term Care.

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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.
 

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I've never been one to make New Year's resolutions. I figure if it's important and something I should do, why wait until January 1 to start? However, New Year's resolutions can be a good way to get people thinking about ways to improve their health. NovaNewsNow.com has a good idea for a practical and useful resolution: better hand hygiene. The article contains some good tips on when hand hygiene is needed. Hand hygiene is the term used for hand washing or use of alcohol-based hand sanitizers, and hand hygiene is one of the most (if not the most) effective and important infection control tools in hospitals, and in the community. Despite this, most people don't perform hand hygiene often enough (or properly), resulting in unnecessary risks of disease transmission.

Have a Happy New Year, and clean your hands.

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I had an advice call the other day about control of Tritrichomonas fetus in cats. This protozoal parasite is being recognized as an important cause of diarrhea in cats, particularly in crowded situations such as catteries. In addition to the standard discussion about control of this parasite in cats, the question about human risks was raised. Tritrichomonas fetus is passed in the stool of infected cats, and other cats become infected by ingesting the organism. It is certainly possible that someone with an infected cat could be exposed to this parasite through inadvertent ingestion of the parasite following contact with infected surfaces (e.g. the cat's fur or litter box). Although this sounds gross, it probably occurs more often that we think. We encounter bacteria of fecal-origin regularly throughout the day.  Keep that in mind the next time you don't want to be bothered washing your hands. 

The risk of human infection with T. fetus is unclear, but is probably quite low. There is only one report of human infection by this parasite, and the person was immunosuppressed. Risks to healthy people are probably very low but we can't say there is no risk. Basic hygiene measures (especially hand hygiene and good litter box management) should reduce the risks even further. People with weakened immune systems should take greater care (because of the risks from this organism and many others), but still, common sense practices are the key.  More information about household infection control and litter box management for cat owners is available on the Worms & Germs Resources page.

Some excellent information on Tritrichomonas fetus can be found on the website of Dr. Jody Gookin, a leading researcher in this field.

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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.

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Back in the 1980s, Vietnamese Pot-Bellied Pigs were a popular fad pet.  These stout little oinkers are still out there, though they're not quite as popular as they once were.  Potbellied pigs are cute (at least to some people... to each their own!), supposedly quite smart, and can even be house trained/litter trained.  As with any new pet though, it's very important to do your research before going hog-wild and getting yourself a pot-bellied pig.  Talk to your veterinarian about what your pig will need in terms of medical care - vaccines, deworming, spay/neuter, hoof trimming, tusk trimming... Because they are uncommon pets, some veterinarians may not be comfortable treating a pig.  Make sure you ask ahead of time so you know to which veterinarian(s) in your area you can (and will!) take your pig.

We recently received a question about vaccination of pot-bellied pigs.  Just like dogs, in some areas pigs need to be licensed by the city, and certain vaccines are required in order to obtain a license.  In this particular case, pigs are required to be vaccinated against rabies, swine erysipelas and leptospirosis.  Regular visitors to this site are no doubt familiar with the issues around rabies and why it's important to vaccinate for this deadly disease.  (More information about rabies is available on the Worms & Germs Resources page and in our archives.)  Swine erysipelas is a systemic bacterial infection caused by Erysipelothrix rhusiopathia, which can rarely cause a skin infection known as erysipeloid in humans.  This is not to be confused with human erysipelas, which is a skin infection caused by various species of Streptococcus (particularly Streptococcus pyogenes). 

But the question was about leptospirosis vaccination in pot-bellied pigs.  Pigs are susceptible to infection by Leptospira interrogans, just like dogs and people, and if infected a pet pig would be equally capable of shedding the bacterium in its urine and potentially transmitting the disease.  The issues around requiring vaccination of pigs for leptospirosis are very similar to those around making leptospirosis a "core" vaccine in dogs.  More information about this is available in the Worms & Germs post entitled "Should all dogs in Ontario be vaccinated for leptospirosis?"  A pet pig would likely be exposed to the same serovars of Leptospira as a dog kept in the same area, typically by coming in contact with urine from infected wild animals such as raccoons and skunks when they go outside.  However, the risk of exposure for a pig that rarely or never leaves the house would be extremely low compared to a pig that has outdoor access.  Another important consideration is whether or not the pig vaccine is against the same serovars that a pet pig, instead of a commercial pig, might encounter.  This will also vary depending on in what area the pig lives.  The Leptospira servoars pomona and bratislava are actually host-adapted to pigs.

It is also important to vaccinate an animal with vaccines that are labeled for use in its own species.  Vaccinating a pig with a vaccine meant for dogs could have unpredictable results - it may increase the risk of an adverse reaction, or it may not adequately stimulate an immune response, thereby leaving the pig essentially unvaccinated.  Your veterinarian can discuss the pros and cons of vaccination in your pet with the available vaccine products.

More information about leptospirosis is also available on the Worms & Germs Resources page.

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The weather outside is frightful (at least up hear in Canada!) - it’s getting colder, the weatherman now warns us about “flurries” instead of “showers”, there’s frost on the cars in the morning, and we’ve all had to start putting on those extra bulky layers before leaving the house in the morning. There's lots of grumbling about the oncoming winter weather. Let’s take a look at the silver lining though – people who live at more northern latitudes often don’t appreciate what a few months of cold weather does for us!

Insects in particular, including mosquitoes, ticks and others that transmit various diseases, are almost entirely inactive outdoors when it’s cold outside. Many insect species can’t even survive Canadian winter weather, which is why they are only concerns in more southern climates. For example, the brown dog tick (Rhipicephalus sanguineus), which can transmit many diseases including canine babesiosis, anaplasmosis, and Rocky Mountain Spotted Fever (RMSF, which can also be transmitted to people), doesn't exist in Canada except on dogs that have travelled to the south.  The cold weather also helps keep heartworm in check through mosquito control - the prevalence if heartworm in North America decreases dramatically the farther north you go.  Bacterial pathogens are often good at surviving in the cold, but many are killed by freezing, and even if they can survive, it is almost impossible for bacteria to grow and multiply in the cold. Winter provides a reasonable knock-down effect for a lot of pathogens and parasites that often thrive in the outdoor environment during the summer months.

Of course, microbes and insects can still survive in the same environments where we do over most of the winter – indoors, where it’s nice and warm. So it’s still important to do things like wash your hands after handling your pet and before you handle food. And, as always, come spring we’ll have to be prepared for the return of all those worms and germs as we venture back to our favourite warm-weather outdoor activities.

In the meantime, grumble though we may, try not to give old man winter too hard a time – a few months of freezing temperatures isn’t all bad afterall.

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You may notice a recurring theme in many of our posts and on virtually all of the information sheets on the Worms & Germs Resources page: an emphasis on handwashing. There is increasing emphasis on hand hygiene (i.e. hand washing and use of alcohol hand sanitizers) education in hospitals because the hands of healthcare workers are a major (if not the most important) means of disease transmission between patients. Despite hand hygiene being easy, cheap and effective, people rarely wash their hands as often as they should, and they often don't do it properly.

Most of the research about hand hygiene that has been published has focused on its use and impact in human hospitals, but this area is now also being studied more with regard to animals and veterinary medicine. A study published earlier this year in Veterinary Microbiology provided more evidence that hand hygiene is a critical infection control measure when dealing with animals. The study, coordinated by Dr. Maureen Anderson (of Worms&Germs fame) looked at MRSA carriage rate in veterinarians who work with horses. In addition to finding a high rate of MRSA carriage among these veterinarians (which was consistent with other reports indicating that equine vets are at higher than average risk for exposure to MRSA), the study looked at factors associated with MRSA carriage. Vets that reported routinely washing their hands between farms and those that reported washing their hands after contact with potentially infectious cases had a significantly lower rate of MRSA carriage. That should come as absolutely no surprise, but it's one more piece of evidence that we need to pay more attention to this routine infection control measure, in human hospitals, in veterinary environments and in households.

Remember, the 10 most important sources of infection are the fingers on your hands!

Click here for instructions on how to wash your hands properly.

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Brucellosis is an infection caused by bacteria of the genus Brucella. The most common species of Brucella in companion animals is Brucella canis, which typically causes infection in dogs. This bacterium is very rare in Ontario - in a survey of 2000 dogs, only 0.3% had evidence of exposure to B. canis. So it was unusual that a case of canine brucellosis was recently diagnosed in the province, until it was discovered that the dog originally came from a rescue shelter in the southern USA - an area where exposure to the bacterium is much more common (approximately 8% of dogs).

Brucellosis in dogs typically causes reproductive problems such as infertility and an enlarged scrotum in males, and late-term miscarriage in bitches (breeding females), with few or no other signs of clinical illness. But in some cases the bacteria have been found to infect tissues other than the reproductive tract, including intervertebral discs (leading to back problems), the eyes, the kidneys, or the tissues around the brain and spinal cord (i.e. the meninges). The bacteria, and antibodies to the bacteria, can be very difficult to detect in the early stages of infection. The infection is usually diagnosed by a blood test, but it may take 8-12 weeks before test will yield a positive result.  There are also problems with high numbers of false-positive test results due to cross-reaction with other species of Brucella.  Any positive test result should therefore be confirmed by a second, different laboratory test.

Human infection with any species of Brucella is now uncommon. When illness does occur, the signs are often non-specific (e.g. fever, headache, myalgia), but more severe infections have been reported.  Transmission of B. canis from an infected dog to a person is possible. The bacterium is transmitted by contact of a mucous membrane (e.g. eyes, nose, mouth) with blood, urine, milk, semen, or vaginal discharge from an infected animal. The highest-risk materials (i.e. most likely to contain a high number of the bacteria) are placental tissues and fluids that are passed during whelping (delivering puppies).  Treatment for infection is available, but the course is often long and recurrence of infection can occur.

Although brucellosis is very rare in dogs in Ontario (and Canada in general), here are a few things you can do to help avoid B. canis:

• Always wash your hands right away if you accidentally come in contact with blood, urine, milk, semen or vaginal discharge from any dog.
• Prevent contact between your dog and urine, milk, semen or vaginal discharge from other dogs, especially if you travel with your dog to an area where the prevalence of B. canis is relatively high (such as the southern USA).
• Dogs used for breeding should be tested for B. canis.  Many breeders will require dogs to be tested before allowing their animal(s) to be used, because the infection can be transmitted through breeding and can have such detrimental effects on fertility.
• Newborn pups should be handled as little as possible, but if you must handling them wear disposable gloves and wash your hands as soon as you take your gloves off. Exercise the same precautions when cleaning up the area where a bitch has whelped.

More information about brucellosis can be found on the CDC's Brucellosis website.

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Some people consider tuberculosis to be a disease of historical interest, but TB is alive and well, and spreading. TB is caused by Mycobacterium tuberculosis, a microorganism that can cause severe lung disease. TB rates are climbing rapidly in some countries and the emergence of highly drug resistant strains is a major concern. Anytime infectious diseases become more common in people in the general population, there is the potential for exposure of household pets.  Recently, transmission of TB from humans to different animal species, including a dog, was reported. This follows earlier sporadic reports of TB in dogs. Finding TB in pets, albeit a small number, raises concerns about the potential role of pets in transmission of TB back to people.

Diagnosis of TB in pets is not particularly surprising, since it has been clearly shown by a few other infectious diseases that disease trends in people can sometime be reflected in their pets. It's hard to say if this is an under-recognized problem, an emerging problem or a very rare event that gets a lot of publicity. Really, the only way to tell will be to see what happens over time. Currently, TB is very rare in pets so it is important to keep possible risks and concerns in perspective. There is no reason for pet owners with TB to give up their pets. People with active TB should consider their pets as part of the family, and interact with them as they have been instructed to with people (i.e. if they are supposed to avoid close contact with people they should do the same with their pets).

There is currently no indication that infected pets can transmit TB back to people, and the risks are probably very low. TB is most easily spread through coughing, and pets with TB rarely develop respiratory disease with coughing. That, combined with the rarity of TB in pets, means that the risk of acquiring TB is much, much higher from other people than from pets.  

This is just one more example of the "one medicine" concept, whereby we need to break down the barriers between 'animal diseases' and 'human diseases' (because the bugs are clearly doing so).

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A horse in Ontario was recently diagnosed with Eastern Equine Encephalitis (EEE), a serious neurological disease caused by a virus of the same name, which is transmitted by mosquitoes.  The horse was from the North Durham region.  The last reported cases of EEE in Ontario were in 2004.  A few weeks ago, the Worms & Germs Blog talked about a large number of cases of EEE that have been reported in Florida this year.

Here are some of the key points to remember about EEE:

• Like West Nile, EEE is a seasonal disease.  It is more common in warmer areas, especially some regions of the southeastern US.  It is rare in cooler climates, but occasionally EEE is found in horses in Ontario.
• EEE is usually fatal in horses, and there is no effective treatment.
• EEE can also occur in people, and can be fatal in some cases.
• Infected horses cannot transmit the EEE virus to people, but if a horse gets EEE from the mosquitoes in the area, then people could also potentially be exposed to the virus by mosquitoes.
• A vaccine for EEE is available for horses, but most horses in Ontario are not vaccinated for EEE because it is so rare.  Nonetheless, vaccination can be considered because the disease is so devastating when it occurs.
• As for West Nile virus, avoiding mosquitoes - for both horses and people - is an important preventative measure for EEE.

For more information, see the Worms & Germs Blog post "Eastern Equine Encephalitis – Not Just For Horses", or the CDC's website on arboviral encephalitides.

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People often ask me questions about "Clostridium" in dogs and cats, with the impression that "Clostridium" is a specific disease. Actually, Clostridium is a large bacterial genus (a group of related bacteria), which includes species that range from harmless to deadly. Some of the more important species are described below:

Clostridium perfringens: This is a common bacterium that can be found in the stool of a large percentage of healthy animals and people. It is a common cause of "food poisoning" in people, and is probably an important cause of diarrhea in dogs and cats. Our understanding of the role of this bacterium in disease in dogs and cats is limited by the fact that it is found in so many healthy animals, so simply growing it from the stool of a diarrheic dog or cat does not prove that it is causing the animal's illness.

Clostridium difficile: This bacterium is a very important cause of diarrhea (and more severe intestinal disease) in people, and is possibly an important cause of diarrhea in dogs and cats. It is rarely found  in healthy adult pets, but is relatively common in puppies and kittens.

Clostridium botulinum: This bacterium produces the toxin that causes botulism, a potentially devastating disease that is very rare in dogs and cats. Botulism usually occurs following ingestion of food that has been improperly stored, in which C. botulinum has grown and produced its potent toxins.

Clostridium tetani: This bacterium produces the toxin that causes tetanus, which can occur in dogs and cats, however these species are relatively resistant to this disease. Tetanus usually occurs when a wound becomes contaminated with C. tetani from the soil, followed by growth of the bacterium and production of potent toxins.

Other clostridia: A large number of different species exist, and it is likely that many more clostridia are around but have not been identified and named. Many clostridia are part of the normal bacterial population in the intestinal tract. Some of these can probably also cause disease.

As you can see, "Clostridium" is more than a single bacterium or disease. An understanding of this concept, and the different disease-causing clostridia, is important.  More information on Clostridium difficile can be found on the Worms & Germs Resources page.

Image: Photomicrograph of C. botulinum stained with Gentian violet.  From CDC's Public Health Image Library (PHIL), ID number #1979.

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• Only eat/drink pasteurized dairy products.
• The main risk from cats and dogs (especially cats) is when they give birth. If you have a cat or dog that has kittens/puppies, wear gloves if you have to touch the babies or any placentae. Afterwards, cleaning the area very thoroughly to physically remove any tissue or fluid residue is very important, because most disinfectants cannot kill C. burnetii. Always wash your hands thoroughly after handing newborn kittens or puppies.
  
• On dry, windy days, avoid farms or areas where sheep or goats are kept.
• Avoid sheep and goat farms during the lambing/kidding season.

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Over 50 horses have died from Eastern Equine Encephalitis in Florida this year. The disease, caused by a virus of the same name, affects the brain, resulting in a broad range of clinical signs from behaviour changes to blindness to irregular gait. The disease is also sometimes called “sleeping sickness” because some horses may become severely depressed, with low head carriage and droopy eyes, ears and lips. Almost all horses that develop neurological signs from this infection die. Only 35 cases were reported in Florida in 2006 and 2007 combined.

There are actually three related equine encephalitis viruses – Eastern, Western and Venezuelan – which are called EEE, WEE and VEE for short. VEE is found in South and Central America and Mexico, and occasionally in the southern United States, but has never been reported as far north as Canada (VEE is a reportable disease in Canada). It is unique among the three diseases as the only one in which an infected horse will carry enough virus in its bloodstream to infect a mosquito, which could then pass the virus on to another animal. The EEE and WEE viruses, just like the West Nile virus, do not reach high enough levels in the bloodstream of horses to do this. The mosquitoes usually pick up the viruses from passerine birds, which do not become ill from the viruses (unlike West Nile virus in birds from the family Corvidae).

People can also be infected by EEE, WEE and VEE. About 10 fatal cases of EEE in people are reported in the United States every year. But horses cannot transmit EEE or WEE to humans, even if they’re bitten by the same mosquito. A higher number of cases in horses, however, may mean a higher number of mosquitoes that are carrying the virus. There is no vaccine for these viruses for humans, but there are vaccines available for EEE, WEE and VEE for horses.

In the end, EEE is just one more good reason to make sure you wear mosquito repellent when you’re enjoying the great outdoors during the summer. Visit the Health Canada website for safety tips on using personal insect repellents. EEE is very uncommon in Ontario, but horses that live in or travel to the southern United States should be vaccinated. Talk to your veterinarian about whether or not your horse should be vaccinated. Remember that fly control is also important for our equine companions (and also helps protect them against West Nile!).

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• Most hot spots are easily treated. This typically involves clipping the hair around the infected site and scrubbing the area with antibacterial soap. Sometimes, antibiotics and/or anti-inflammatories are also needed. The infected site should be kept as clean and dry as possible.
  
• While most hot spots are not caused by bacteria that are a major concern for transmission to people or their animals, any infected site should be handled with care. Direct contact with the hot spot should be avoided.
  • If the infected site needs to be touched, gloves should be used if possible, and hands should always be thoroughly washed after touching the site.
  • Care should be taken when touching hot spots because they can be very painful, and touching them could make some dogs bite.
• Prompt examination by your veterinarian will help ensure your pet gets the treatment it needs as soon as possible, and ultimately helps speed recovery.
• Always follow your veterinarian's recommendations closely and completely. Stopping treatment too early can lead to recurrence of the infection, which may be more difficult to treat.

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A small outbreak of the potentially deadly Hendra virus was identified in a group of horses near Brisbane, Australia. This virus has caused periodic cases of illness and death in horses, and can be transmitted to people working closely with infected horses. In the latest outbreak, 3 horses have died, making this the worst outbreak since 1994 when 14 horses and 2 people died.  Now, a human case has been identified. This person works at a veterinary clinic that treated infected horses. This individual was admitted to hospital overnight but was discharged, so is presumably not very ill.

While Hendra virus (genus Henipavirus) is only found in Australia, it is a good reminder for everyone about the strange nature of some infectious diseases. The natural reservoir of the virus is the fruit bat. It is believed that horses become exposed when infected fruit bats give birth and contaminate horse pastures with uterine fluids. Horses develop respiratory disease ranging from mild to fatal. Human cases have been reported in people working closely with infected horses. A horse trainer and veterinarian's assistant died in the 1994 outbreak. Close contact is required for transmission to people.

Picture: Locations of previous Henipavirus outbreaks (red stars – Hendra virus; blue stars – Nipah virus) and distribution of Henipavirus flying fox reservoirs (red shading – Hendra virus; blue shading – Nipah virus)

It's very difficult to take specific measures to protect horses, people or other animals from sporadic, rare diseases such as Hendravirus infection. However, common sense infection control measures can reduce the risks associated with any animal contact.

• Wash your hands after contact with any animal.
• Avoid contact with sick animals - consider sick animals to be potentially infectious until proven otherwise.
• Remember that  new animal diseases are regularly being identified, and that they might be able to infect people.
• People that work in veterinary clinics must be diligent and use good infection control practices because they are at higher risk of exposure to various diseases.

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• Keep cats indoors
• Talk to your veterinarian about a flea control program for your pets
• Never touch wild animals, especially sick or dead ones
• Don't keep wild animals as pets
• Try to keep wild animals away from your pets

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I often get asked about testing of healthy pets for Clostridium difficile. This bacterium is an important cause of disease in people. While most common in people in hospitals, cases of C. difficile infection are occurring more in people in the general population. Also, C. difficile can be found  in various animals, including dogs and cats. This has led to concerns about the role of pets in C. difficile infection in people. The role of animals in human infections has not been determined, but it is plausible that C. difficile could be transmitted between people and pets, in both directions.

I have been diagnosed with C. difficile. Should my pet be tested?
No. There is no evidence that it is useful. Even if C. difficile is isolated from your pet, it would not tell you if the pet was the source. Your pet could be carrying a completely different strain of C. difficile. Molecular typing of the recovered bacteria (from both you and your pet) would be needed to determine if they are the same strain, and this type of testing is not readily available. Even if you both had the same strain, your pet could have picked it up from you. So, testing of your pet really wouldn't tell you anything.

I'm worried that I may have acquired C. difficile from my pet. Can I just have my pet treated at the same time I'm being treated?
No. Treatment of healthy pets to eliminate C. difficile is not recommended. There is no evidence that we can eliminate C. difficile from a healthy pet with antibiotics.

More information on Clostridium difficile can be found in our Resources page.

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A case of pneumonic tularemia was recently reported in New York City.

Tularemia is a disease caused by the bacterium Francisella tularensis.  It causes different signs of illness depending on how the bacteria enter the body.  If the bacteria are inhaled, it tends to cause pneumonia (pneumonic tularemia).  If the bacteria get in through a break in the skin, infection may cause the local lymph nodes (glands) to become very swollen, and in some cases the skin itself may become infected resulting in the formation of large sores (ulcers).  Infection can also cause sores in the mouth and diarrhea.  The earliest, most common signs are things like fever, headache, chills, sore muscles, and sore throat which often come on very abruptly.  The infection can be treated with antibiotics, but it is important to see a doctor and start treatment as soon as possible.

Tularemia is also sometimes called "rabbit fever," because the bacteria are often carried by animals such as rabbits and hares.  Rodents (including beavers, rats, mice, squirrels etc.) can also carry F. tularensis, and occasionally so can cats and dogs.  Some biting insects like deerflies and certain species of ticks can carry the bacteria and transmit it when they bite.  Francisella tularensis can also survive in water and soil for a long time.  People can become infected by being bitten by an infected insect, handling an infected animal (dead or alive), or coming into contact with feces from an infected animal.  Occasionally a person may inhale the bacteria if it is in the air, as may happen with disturbed, dusty, contaminated soil.

More information on tularemia can be found on the CDC's tularemia website.

Things you can do to avoid tularemia:
Avoid touching or handling wildlife (dead or alive), especially rabbits and rodents.
Don't let your pet touch or eat dead animals.
Always wash your hands if you have been working outside in the dirt/soil.
Wear insect repellent containing DEET (visit the Health Canada website for more safety tips) 
Make sure you only wash food with and drink water that has been properly treated.

One of the reasons tularemia is such a big deal is it is very infectious - as few a ten bacteria can be enough to make even a healthy person sick!  But it is still quite uncommon in North America - about 100-200 cases are reported in people in the USA every year.  Between 2002-2004 there were 34 cases reported in Canada, most of which occurred in Quebec and in adults.  However, infection can be fatal in a very small number of cases, especially if proper treatment is not given as soon as possible.

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