Some findings are pretty logical, clear and indicate something that should be done.

• Smoking is a risk factor for [insert many diseases here], so to reduce the risk of [whatever disease], stop smoking.

Others make sense but don’t necessarily lend themselves to an effective intervention.

• Being male is a risk factor for cardiovascular disease... not much I can do about that.

Sometimes, you have to remember that a risk factor for one thing doesn’t provide a clear answer when a broader context is considered.

• Moderate consumption of red wine can reduce the risk of various conditions, but alcohol consumption can also increase the risk of other conditions.

Sometimes, how the study is designed and performed can really affect the results.

• If I did a large study of the general population in Guelph, I could presumably show that going to a hospital greatly increases your risk of death. Does that mean you shouldn’t go to the hospital? No, because I could presumably also show that if you have chest pain and go to a hospital, you’re more likely to live. Knowing the study population and what question is really being asked are critical.

Sometimes, something that’s found to be a risk factor isn’t really the risk factor, but it’s associated with something else that is.

Sometimes, something can be "statistically significant," but of limited consequence.

• If doing something increases the risk significantly, but only by 0.0001%, does that mean anything?

Why do I write this? Because these are some of the things that we have to think about when assessing risk factor studies. While one Toronto radio station loves to give 10 second snippets on some new risk factor medical study, you can’t determine much about the study itself from a sound-bite (or internet post). You need to think about the details regarding how the study was done. Nevertheless, risk factor studies can provide useful information, but consider the results carefully, whether they are relevant, whether they indicate changes need to be made or whether they indicate that we need to look at the issue further.

Anyway, this rambling post was prompted by a couple of papers looking at risk factors the leptospirosis in dogs (Hennebelle et al J Am Vet Med Assoc 2013 and Raghavan et al Prev Vet Med 2012)

The first study compared dogs from northern California that had or didn’t have leptospirosis. They found a few things:

• There were differences in geographic distribution of the lepto cases and controls. That makes sense since we know lepto varies regionally, but living in different areas might also be associated with different behaviours and contacts (e.g. wildlife contacts).
• There was a temporal cluster, with more cases occurring between May 2003 and May 2004, compared to the rest of the 2001-2010 study period. That makes sense too since we see variation in cases within and between years.
• These results don’t change anything, but are an indication of what work needs to be done next. Looking at why things vary geographically and temporally might be important for figuring out how to reduce the risk of disease. It also indicates regions where more efforts to educate pet owners (and veterinarians) are indicated, and where vaccination is more important.

The second study looked at dogs from Kansas and Nebraska, with and without leptospirosis. They also found a few risk factors.

• Lepto was more common in houses lacking complete plumbing facilities. Presumably, this is a proxy for something else. Poor plumbing doesn’t likely result in lepto in dogs. Rather, it presumably means that a dog living in a house with poor plumbing has some other factor that increases its risk. For example, incomplete plumbing may be more likely in lower socioeconomic (i.e. lower income) households, which might then correspond to other more direct risk factors for the dog (e.g. poorer nutrition, less veterinary care). It could also be that houses lacking complete plumbing tend to be in a different area where there’s more exposure to wildlife reservoirs. A couple of other indicators of poverty status were also significant, highlighting the potential impact of owner poverty on pet health.
• Dogs that lived within 2500 m of a university or college, or a park, were also at increased risk. The park risk factor makes sense since they could be exposed to sites infected by wildlife reservoirs (e.g. raccoons). Living close to a university or college is tougher to figure out. Maybe it’s associated with economy, as students are typically at lower income levels. Maybe it’s because colleges and universities usually have lots of green space that might harbor wildlife.

So, these studies tell us some new information, reinforce some previous knowledge (or perceptions) and raise some new questions that we need to answer. By themselves, they won’t result in major changes in how we try to prevent lepto in dogs, but little steps is typically how science progresses.

What protocol would go into place if a horse with a highly contagious disease such as EHV-1 were to be found at a competition in Canada?

The short answer (to the surprise of many) is that there is no pre-established nation-wide protocol for most equine disease outbreaks.  Every outbreak is managed differently, based on the disease, the types of horses, where exposure might have occurred and a range of other factors. Typically, a disease like EHV isn't going to be noted during the show, since it takes some time for illness to develop after exposure. Therefore, the response is more of an investigation of what happened at the show, why and how it can be prevented in the future, and of course trying to prevent further transmission in the community (e.g. identifying exposed horses, communicating with people who have been to the show with recommendations to quarantine and test exposed horses and potentially all horses, surveillance for ongoing transmission from horses that have left the show).

With horses, there's no regulatory body with a mandate to oversee (and fund) this type of investigation unless it's a federally reportable disease like rabies (and even then, assistance may not be forthcoming). Some provinces have more authority and interest (e.g. the Animal Health Act in Ontario gives the province a mandate and powers to intervene) but often investigation is not a priority for regulatory bodies and it's left to whoever is around and interested. There are some good outbreak management guidelines from different institutions or groups (e.g. the ACVIM consensus statements on EHV and strangles) but there is no standard approach. Because testing costs are placed on the owners, responses can be quite variable since getting people to test when indicated can be a challenge. Additionally, getting people to follow quarantine recommendations is a challenge because of inability to effectively quarantine on their farm or unwillingness to do so (usually more the latter). So, each outbreak ends up being managed quite differently.

In general, the key points to outbreak investigation and management are:

• Identification of a problem
• Diagnosis of the problem
• Communication to let people know what's happening
• Identify potentially exposed and infected horses
• Quarantine, if appropriate (usually some form of quarantine is indicated, but not necessarily for all diseases)
• Develop testing recommendations
• Develop and communicate a plan to maximize compliance with quarantine and testing
• Create a way to centralize data collection and communications, so that a clear picture of what is happening is obtained
• Keep people in the loop as the investigation ensues to maximize compliance and decrease loss of compliance because of boredom or fatigue with the recommendations

Recently, a horse in southwest Queensland was diagnosed with Australian bat lyssavirus infection. This virus, which is similar to rabies, is present in some bats in Australia. It can be transmitted to people from bats, causing fatal disease, but human infections are very rare. Even though it's rare, it warrants attention because the disease is so severe.

Finding an infected horse is surprising in some ways, because the virus has never been detected in this species before. However, a virus that's present in bats can certainly find its way into a horse, and we already knew that a closely related virus (rabies) can infect horses. So, maybe it's not that surprising afterall.

In this case, the horse was suspected of being infected with Hendra virus initially. While Australian bat lyssavirus can kill people, this diagnosis was actually much better than Hendra virus infection, because horse-human transmission of Hendra is a major concern. Hendra virus infections have high fatality rates and, perhaps most importantly, there are no effective preventative measures that can be taken after Hendra virus exposure. Since Australian bat lyssavirus is so closely related to rabies virus, rabies post-exposure treatment can be used in this case (and is probably effective).

It's unclear whether an infected horse poses much risk to people. The very small number of human Australian bat lyssavirus cases have occured in people who were bitten or scratched by bats. Since this is the first equine case, it's not known if affected horses shed large amounts of (or any) virus. People who had contact with the horse were identified and offered post-exposure treatment. It's reasonable to consider this situation like rabies exposure in the absence of more evidence, and treat people who were bitten or otherwise may have gotten virus-contaminated saliva into their tissues via broken skin or mucous membranes.

Is this the start of yet another new problem?

Most likely, this is just an example of the rare scenario of a virus infecting an atypical host, not the start of a new, common problem. However, it's worthy of attention in case the virus has changed or there is now a specific virus type that can more easily infect horses (both very unlikely). This case also shows the importance of thorough diagnostic testing, particularly when an animal has severe disease.

If you don't look, you don't find.

If you don't find, you can't act.

A paper in BMJ Case Reports (Tumram et al 2012) describes a rather unusual and unfortunate situation. It's about a fatal infection in a 55-year-old Indian woman who was bitten by a mongoose. She was bitten (unprovoked, it seems) on the leg by the mongoose while washing dishes. She went to the hospital a couple of hours later because of pain and swelling in her leg. It's not clear what happened there, but she went back to hospital the next day, and then received antibiotics. However, that same day, she suffered cardiac arrest (a heart attack) and died a few days later. The bacterium Streptococcus pyogenes (Group A Streptococcus) was isolated from some lesions on her legs, leading to a suspicion that she developed a severe and rapidly progressive infection from the mongoose bite.

Various aspects of this case are unusual. Fatal bite infections occur, but they are rare. Involvement of streptococci is rarer still.

Why did this woman develop a fatal infection, especially when she sought prompt medical care? It's hard to say, and there is a "bad luck" component of infectious diseases. She had diabetes and high blood pressure, which probably increased her susceptibility to infection (but lots of other people who get bitten also have these conditions and suffer no consequences). It doesn't appear that she received antibiotics when she went to the hospital originally, but a bite over the leg isn't one that would always be treated prophylactically with antibiotics.

Why did the mongoose bite? That's another good question. Unless you're a snake, mongooses are typically not aggressive.

Where did the bacteria come from? We don't know much about the oral bacterial population of mongooses, but Streptococcus pyogenes is a human-associated bacterium. It's rarely found in animals and I suspect that the strep didn't come from the mongoose. Rather, it was probably already on the woman's skin and introduced into her body by the bite, or she contaminated the wound after being bitten. It's just a guess, and it doesn't change anything, but it makes sense.

This report shouldn't make people freak out over a bite. However, it should serve as a reminder that bad things can happen. More information about dealing with bites can be found on the Worms & Germs Resources - Pets page.

Image: Dwarf mongoose (Helogale parvula) in Korkeasaari zoo (photo credit: Miika Silfverberg, click image for source)

A recent paper in the journal Mycoses (Van Rooij et al 2013) highlights one such scenario. The paper describes ringworm in a dog that was associated with the fungus Trichophyton rubrum, which is not the typical ringworm species (Microsporum canis) that we find in dogs. Trichophyton rubrum is a common cause of infection in people, particularly tinea pedis (athlete’s foot) and onychomycosis (fungal infection of finger and toe nails). The authors did something that’s often lacking in reports of animal-human transmission: they actually tested both the person and the pet. Here, they found that the owner was a carrier of this fungus. They were able to isolate the fungus from his skin and determined that he likely had an asymptomatic infection that was subsequently transmitted to his dog. (He’d previously had untreated and self-resolving athlete’s foot, and presumably remained a carrier after that). Since this ringworm species is predominantly found in humans, it’s a reasonable assumption that it started with the person and the problem was only identified when the dog developed disease. In this case, the dog was old and had been treated with corticosteroids, both of which probably affected it’s immune system and made it more susceptible to this uncommon cause of canine disease.

It’s important to remember that while zoonoses are important, pathogens go both ways.

In the end, we’re all animals.

Yes, there are now diapers for chickens.

I understand the whole urban chicken concept. I don't actually have many issues with it if it's done right - but that's a big IF, unfortunately. Keep your chickens on your property, don't do it if you have young kids or other high risk individuals in the household, use good basic hygiene practices, feed them right, don't get roosters, and don't run screaming to the newspapers or local politicians if some get eaten by carnivorous urban wildlife. The nuisance and risk of backyard poultry can be limited.

Live chickens inside the house... that's another story.

Chickens aren't house pets in my world. I'm not sure if the chickens benefit at all from living in a house with people, and it's probably actually detrimental in many ways. I'm not sure what the benefit is to people either. Although I haven't seen any studies on this specific topic, it stands to reason that keeping a chicken indoors would be associated with a fairly high risk of widespread contamination of the household with bacteria like Salmonella and Campylobacter, two bugs that cause millions of infections in humans every year.

I'm all for risk mitigation, including using creative (and sometimes off-the-wall) measures - but diapers for chickens?  Not so much.

Yet, Pampered Poultry makes diapers for your indoor chickens, and not just run-of-the-mill diapers: they're (allegedly) both functional and fashionable. This isn't the only company that sells chicken diapers either, much to my surprise.

One website states "Our chicken diapers are not just for the fashion obsessed hen. They offer your and your home protection against the inevitable! Our diapers fit comfortably and allow you to enjoy your birds in the house or car [car?] without worry."

Does using chicken diapers make sense?

I have a hard time believing these diapers are very useful. They probably do reduce the burden of pathogens that are deposited in the environment, but they are presumably far from 100% effective at containing all of a bird's droppings. It's also likely that chickens are contaminated with these bacteria on other parts of their bodies. Thinking you've eliminated the risk of household contamination from your pet poultry by using diapers isn't logical. The diapers also need to be changed (risk of more contamination) and disposed (don't we have enough waste already?) or washed (risk of cross-contaminating other items).

If you want fashionable chickens, go ahead and dress them up in diapers. Nothing says haute couture like a chicken walking around the living room in pink floral undies. Just don't convince yourself that you're reducing the infectious disease risk for other animals and people in the house. Better yet, let the chickens be chickens and keep them in a proper coop outside. I've seen too many indoor goats, pigs, miniature horses and other species with profound health problems from owners thinking they're just like people.

Apart from diapers, the store also sells "saddles" for the chickens. I'm not even going to start on that one.

I don’t have any firsthand knowledge about this case (or any information beyond what’s been written elsewhere), but as far as I know, this is just a single sporadic case. That doesn’t mean an outbreak can’t occur, but most often, these just occur singly.

Whether there’s cause for concern is a tough question to answer. Yes, EHV-1 can be a serious problem, causing neurological disease in adult horses, abortion in pregnant mares, and severe disease in neonatal foals. Yet, at the same time, it’s an endemic disease that most often occurs as sporadic cases rather than large outbreaks (people just don’t hear about single cases as often, although they are now reported a lot more than they were a few years ago). The EHV-1 virus is very common and can be found in its dormant form in a large percentage of horses, so it’s not like some pathogens with which an unexposed population can suddenly be threatened when a single case is identified. In general I pay close attention to EHV-1 cases, but they are not a cause for panic. If a case occurs, we need to see if some broader issue is at play, and put steps in place to limit the problem, but we don’t need to cause massive disruption. In short, we want to ensure that good surveillance and infection control measures are in place, but not freak out in the process.

People have really taken a 180 degree turn in how they handle EHV-1 over the past 10 years or so. I don’t think we see EHV-1 neurological disease any more than when I was a resident. Back then, we saw sporadic cases and the odd small cluster, and people didn’t get too worked up about it in terms of the risk of transmission. Outbreaks, such as one I can remember associated with a large Ontario Standardbred yearling sale, certainly got lots of attention, but it was short-lived. Things changed (for good reason) based on some large, high-profile outbreaks in the last decade.  It’s not known why such outbreaks now seem to be more common.

Anyway, if you live in Ontario and have a horse, don’t panic. Your horse is probably at no greater risk today than it was last month, assuming it wasn't in contact with the affected horse (which was diagnosed in early April). Virtually every horse is at some degree of EHV risk every day, but the odds of disease occurring are very low.

Some key prevention tips include:

• Use good general infection control practices to reduce exposure of horses to pathogens brought in by newly arrived horses.
• Observe your horses regularly and if there are any problems, isolate the horse and have a veterinarian examine it ASAP.
• When travelling to shows, races or other events, take measures to reduce direct and indirect contact between horses.

More recently, another canine flu virus has emerged in dogs, this time a type H3N2 in Asia. H3N2 is a common human flu type, but birds are the ultimate reservoirs of all flu viruses, and based on the genetic relationship of H3N2 from dogs and birds, it's thought that this virus came to dogs from birds.

Anytime a new infectious disease is encountered, it's important to figure out who/what it can infect. When H3N8 CIV emerged, it was shown that even though it came from horses, it was no longer adapted to readily infect horses. So, knowing a virus' origin or typical infection trends can be useful but it doesn't necessarily tell you the whole story.

Cats and ferrets are susceptible to many different types of influenza viruses, and are good species to look at when figuring out if a virus can spread to other domestic animals. A study in the recent edition of Influenza and Other Respiratory Viruses (Kim et al, May 2013) looked at transmission of H3N2 CIV between dogs, cats and ferrets.

In that study, researchers infected dogs with CIV and kept them in close proximity to cats and ferrets, but without direct contact. They also infected cats and ferrets to see whether they could transmit the virus to other cats or ferrets.

Here are some highlights from the study:

• All directly infected animals developed some degree of illness, with cats and dogs typically developing sneezing, coughing, increased respiratory effort and nasal discharge, and ferrets only developing sneezing.
• Cats could become infected by being in proximity to both infected dogs or infected cats.
• Ferrets didn't get infected when exposed to infected dogs.
• Ferrets did not develop disease after exposure to an infected ferret but 2/3 developed antibodies against CIV, meaning the virus had been transmitted, but not able to cause disease.
• Cats shed higher amounts of virus than ferrets.
• Dogs stopped shedding the virus by day 8 after infection. That's not surprising since influenza shedding is short-term with H3N8 CIV. It shows that use of good infection control measures, particularly isolation, can be a key component of canine flu control.

So...

• Dogs with H3N2 CIV are potential sources of infection for cats and ferrets.
• Cats that are exposed to the virus can get sick and be sources of infection for other animals, presumably including dogs. Cats may be another truly susceptible host for this virus.
• Ferrets seem pretty resistant to the virus. It probably takes fairly high level exposure for them to get infected and they are less likely to be of concern for subsequent transmission.

Interspecies transmission of flu viruses, and other viruses, is obviously an issue. Most of the attention is paid to the bird-pig-human cycle, for good reason. Birds are the reservoirs of all influenza virus variants, pigs are  susceptible to both human and bird flu viruses and can act as a "mixing vessel," and humans are the species we're ultimately most concerned about. However, the potential for disease in pets and for pets to be reservoirs of influenza for people or other animals shouldn't be neglected. I've frequently had discussions with colleagues in the medical and public health fields about the need for parallel companion animal surveillance when plans are made for emerging infectious disease surveillance and response (e.g. SARS, H1N1 flu, novel coronavirus). They typically respond with general enthusiasm, but interest and application aren't the same, and actually getting plans in place to perform coordinated parallel surveillance hasn't happened. Studies like this are just one more piece in the puzzle that indicate the need for broader surveillance and consideration of pets.

"Hot spots" (aka focal bacterial pyoderma) are common skin infections in some dogs. Meg has  underlying skin issues and lately has spent a lot of time wallowing around in ponds (because that's what she likes to do). With her skin issues, potentially weaker immune system because of her advanced age, and frequent wetness, she's a bacterial skin infection waiting to happen. 

The latest hot spot is under her neck, and was evident by some colour change in the area (picture #1) and a bit of scratching, along with an odour if you get really close. These signs can easily be missed, especially early on, as the infected site is a bit hidden. Often, people only notice when it gets really wet and stinky, or when the dog scratches at it incessantly. Clipping the area revealed a more extensively affected area (picture #2) and a couple of focal spots with some pussy discharge.  (It's quite amazing what can be hiding under an animal's fur!)

A hot spot is caused by a bacterial infection, and it's almost guaranteed that it's a staph infection (most likely Staphylococcus pseudintermedius). I took a swab from the affected area for culture. That's probably not critical in a case like this, especially when I'm going to treat it topically and without antibiotics, but since I can do it myself, it never hurts to have the information with regard to what bug is responsible (particularly if the infection comes back again).

The approach to treating hot spots is pretty straightforward, and owner compliance is key. Here's the plan:

Clip the area

• This helps identify the extent of the problem. It also (very importantly) helps keep the area dry and facilitates topical treatment.

Keep the animal from traumatizing the site

• That's been easy so far with Meg since she's not really scratching at it. If she was scratching, we'd need to put on an Elizabethan collar or use some other form of protection. In some cases, corticosteroid anti-inflammatories are needed to control the itch (and thereby the scratch).

Keep it dry

• Easier said than done. Despite being old and lazy, Meg is very motivated when it comes to lounging around in whatever water she can find (including the other night at 3:00 am... don't get me started on that one). Other than that, since the site is clipped now, keeping it dry is not a major problem.

Topical therapy

• This is a bacterial infection, but the advantage of skin infections is that skin's on the outside. We can treat it topically and avoid using oral or injectable antibiotics. There are various things that can be done this way, usually involving bathing, wiping or spraying the area with topical antiseptics. We're using an antiseptic spray on Meg.

Infection control

• Nothing major. It's unlikely that the cause is something zoonotic (and if it's MRSA, she presumably got it from someone in the family!). The staph that typically cause these infections are common inhabitants of canine skin. They rarely, if ever, cause infections in the absence of some inciting cause so Merlin (the other dog) and Finnegan (the cat) are unlikely to get an infection from Meg in this situation.
• A little handwashing goes a long way.

Hopefully I don't get to write about the massively increasing hot spot next week.

The test claims to diagnose urinary tract infections (UTIs) by  "detecting blood, leukocytes (AKA white blood cells) and nitrite in animal urine." Unfortunately, it cant.

• Blood in the urine does not necessarily mean there is an infection (i.e. this is a non-specific sign). In fact, a minority of cats with blood in their urine have an infection. They are much more likely have another problem like idiopathic cystitis that needs to be treated differently than an infection.
• Urine test strips for white blood cells are notoriously useless in animals. Maybe they have a better, more useful version, but I doubt it.  The best way to detect these cells in the urine is to look for them using a microscope.
• Nitrite can be produced by bacteria in the urine but it has little to no diagnostic value in dogs and cats.

There's no mention about any specific evaluation of the test (i.e. they haven't checked to see if the test actually does what it's supposed to). By the look of the picture, it seems to simply be a urine dipstick in a fancy holder marked up a couple thousand percent to make money. Actually, it seems to be an inferior type of dipstick since it only tests for 3 things, two of which are useless.

Not surprisingly, the test is to be used in conjunction with their supplements (which probably explains why a supplement company decided to enter the diagnostic testing business).

The test isn't exactly cheap either: $39.95 for dogs and $49.95 for cats (the only difference to me being the cat kit comes with a bit of non-absorbent litter to put in the litterbox to collect urine, with a nice markup there too). While marketed as a way to save money on veterinary bills, think hard about what it will really do. Beyond potentially providing misleading information that could impact proper care, it will probably end up costing owners more:

• If the test is negative and the pet has urinary tract issues, it needs to be seen by a veterinarian to find out what's going on.
• If the test is positive, the pet needs to be seen by a veterinarian to get treated. No competent veterinarian is going to prescribe a treatment based on an at-home test like this. So, the full range of testing will be done anyway.

Ultimately, if the pet is sick, it needs to see a veterinarian. If it's not sick, there's no indication for testing like this.

If you want to know some real facts about diagnosing UTIs in dogs and cats, check out the International Society for Companion Animal Infectious Diseases Guidelines for diagnosis and management of UTIs in dogs and cats.

If you still think this test is worth the money, I've got some great oceanfront property in Saskatoon that I'll sell you (see photo). The water skiing is particularly good in January.

It's a good question to ask because MRSP (methicillin-resistant Staphylococcus pseudintermedius) is a highly drug-resistant bacterium that causes a lot of problems in dogs, and because of the high profile of its relatively distant relative, MRSA (methicillin-resistant Staphylococcus aureus), in people.

The short answer is: Yes, MRSP can infect people

BUT... (and it's a big and important but):

It's exceedingly rare and the overall risk is very low.

Here's my reasoning behind this answer:

1) Reports of MRSP infections in people are very rare.

• I think there are only two such published reports at the moment. There have probably been more infections than the number that are published, and there's the potential for MRSP to be misdiagnosed by some human diagnostic labs (meaning some MRSP infections may be mistaken for something else), but I think it's fair to sayl this a very rare infection in humans.

2) MRSP is not well adapted to infect people.

• MRSP is not inherently any more likely to cause infection than methicillin-susceptible strains of S. pseudintermedius (MSSP).
• MSSP can be found on basically every dog.
• A large percentage of the human population has contact with dogs every day.
• So, a large percentage of people encounter MSSP every day. Yet, reports of MSSP infection in people are very rare. To me, that indicates that this bacterium is poorly adapted to be a human pathogen.

3) Veterinary dermatologists are not extinct.

• MRSP is very common in dogs with skin infections. In some practices, it's the main cause of these infections.
• That means veterinary dermatologists encounter a lot of MRSP every day.
• I have yet to hear a report of a veterinary dermatologist getting an MRSP infection (carriers yes, disease no). I wouldn't be surprised if there actually have been some infections, but dermatologists can be considered the canaries in the mine when it comes to human MRSP risk, and I'm not aware of any real issues.

4) All dogs are biohazardous

• While this may not comfort the people calling me who are worried about the health of their families, it's important to put things into perspective. All dogs are carrying multiple microorganisms that could cause disease in people under the right circumstances (and the same goes for all cats, horses, people etc. for that matter).
• If you screened the average dog, you'd find things that are of greater concern that MRSP. In fact, MRSP probably barely cracks my "Top 10 List" of things I'm worried about the average dog spreading.

So, yes, there's a risk of MRSP infection when a person has contact with a dog infected with or carrying MRSP. There's also a risk of infection from methicillin-susceptible S. pseudintermedius, the version of the bug that basically all dogs carry, and a whole range of other bugs.

There will never be a zero-risk pet when it comes to zoonotic diseases. It's impossible. The risks may be very low but we can never eliminate all risk, just like we can never eliminate all risk from walking down the street. For some people, that slight degree of uncontrollable risk might be too much to handle, and they probably shouldn't own a pet. For most, the positive aspects of pet ownership outweigh the risks, and some basic hygiene practices (e.g. handwashing, avoiding licking, avoiding contact with the dog's mouth, nose and bum) can reduce that already low risk even further.

“Show me the peer-reviewed publication.”

This is a common refrain used, particularly by the scientifically-minded, when talking to someone about the latest trendy diagnosis, treatment or other medical "discovery." It used to be relatively easy to use this method to assess the reliability of new information. If something was published in a peer-reviewed journal, it was probably at least reasonably sound (not always, but it did provide a greater level of assurance).

Now, it’s getting tougher.

One reason for this is the proliferation of online journals in particular. Some are legitimate journals that have been created by people that perceived a need in a specific area. Yes, with more research, more journals can be supported. Some good journals reject 50-90% of submissions, and many rejected papers are still valid and indeed important. Having a wide range of journal options is important because everything can’t be published in Science, Nature or the New England Journal of Medicine.

But, there’s a limit.

I review a lot of papers for journals every year. Sometimes, I end up reviewing the same study a few times for different journals, after I’ve recommended rejection previously. Some of these get accepted if they are a better fit for the journal (e.g. scope of the study, priority of the type of research for the journal) or they end up making substantial changes to improve the manuscript. However, I’ve also rejected some papers a few times and eventually seen them published in pretty crappy journals. The sad reality is that marginal research can usually be published somewhere if the authors are persistent. Most people in academia know the strengths of journals in their field and can approach a paper in a "bottom-feeder" journal with care, but the general public doesn’t know that, may not have access to the full paper, and probably wouldn’t be able to assess the quality of the study anyway. So, just knowing that something’s been published in a peer reviewed journal these days only tells you part of the story.

Even worse, thousands of new journals have been created by for-profit groups. That doesn’t inherently mean they are bad, but it’s getting clear that for some, the size of the cheque is probably more important than the quality of research. I get emails from them pretty much every day from one group advertising a new journal, asking for journal submissions or requesting that I serve on their editorial board (yet curiously, I’ve never been asked to peer-review a paper for one). Unsuspecting academics have signed onto editorial boards thinking they were legitimate and have had a hard time getting their names removed once they realize the problems.

Some of these journals use impressive sounding names or ones that are very close to highly respected journals, further confusing the reading public.

All these things make it hard for the average person who wants to explore something a bit further to know what information can be trusted. Not only do you need to think about whether a study is published, you need to figure out if the study is valid and published in a reputable journal where the research was actually scrutinized, not published just because the authors paid a few thousand dollars for the publication fee.

Some of these for-profit groups sponsor scientific conferences that have the same issues. Normally, conference presenters are invited by scientific committees made up of experts in the area and/or are chosen through submission of research abstracts that undergo review. The more dodgy conferences solicit abstracts (I probably get an email a day from these) and get people to attend conferences, but then send them a bill at the end. So, they sucker paying attendees by making the conference look real (sometimes by putting names of high profile people as organizers or presenters without their knowledge) and get more money by charging presenters (thereby getting money from people who will pay to get their research presented or others with good research that are unsuspecting). In the end, you might be left with good research or invalid research, and it’s hard for the average person to sort this out.

There’s a good article in Nature about this subject, as well as a related article recently published in the New York Times.

How do we get this get under control? I have no idea.

Being someone who deals exclusively with infectious diseases and does surgical site infection (SSI) research, I have to think about his risk of developing an infection and how to prevent that.

Infection rates after neuters are very low. Actually, I can’t say that with confidence since we don’t have good data to back it up. We just finished one of the largest surgical site infection surveillance studies in dogs and cats, but being based at a tertiary care referral hospital, we didn’t get any data on neuters. I’m not aware of any private-practice-based studies that have assessed SSIs in dogs and cats, so my initial statement is just based on the fact that I don’t hear much about SSIs after neuters, and when I talk to people in primary care practices, they don’t report many of these infections. They occur, but they probably are truly rare.

However, rare doesn’t mean it will never happen, so pet owners need to be aware of what they can do to reduce the risk of post-operative infections (and then actually do it).

It’s been said in human medicine that the most critical time for preventing (or causing) SSIs begins and ends in the operating room. I think that’s true for animals as well, so there’s not much that the pet owner can do about that part except choose a good veterinarian, and not be afraid to ask pointed questions about the clinic's infection control measures. The pet owner’s major role is taking care of the animal after surgery.  Here are a few things that I need to do for Merlin:

• Restrict his exercise for a few days. Trauma to the incision site will increase inflammation and the chance of an opportunistic infection developing.
• Keep him from swimming (or more accurately, wallowing in the swampy areas and ponds around home). Keeping the incision dry is important for good wound healing.
• Keep him from licking the wound. This a huge factor and one that people often mess up. Yes, he hates his Elizabethan collar (i.e. the head cone). However, it’s important that he wears it to keep him from damaging the incision site and seeding it with bacteria from his mouth. It’s a matter of short-term pain (annoyance, actually) for long-term gain.
• Keep an eye on the incision. A little inflammation (e.g. redness, swelling) is normal. If it increases or any discharge develops, that might indicate a developing infection. If that occurs, getting him re-evaluated ASAP is important.
• Make sure he goes in for his recheck, and that it’s done on time. This is important to detect problems in a timely fashion and to remove his sutures. (Merlin will presumably get his "recheck" at home, since the two DVM degrees Heather and I have hopefully give us the collective ability to remove a few stitches ourselves and determine if the incision is healing okay.)

None of this guarantees Merlin won’t get an infection, but these measures are all important. There is a non-preventable fraction of infections - meaning some will occur despite everything you do. However, a large percentage of SSIs are preventable and these basic practices can help.

Since nothing says summer like hookworms, here's a new info sheet all about hookworms, including information on cutaneous larva migrans. The sheet can also be found on the Worms & Germs Resources - Pets page, along with info sheets on many other topics.

Anyway, beyond quibbling about the title, there are some interesting parts to the tragic story.

The article describes the death of a young boy. He was attacked by a dog while playing in his front yard in the Philippines. After the attack, he was taken to the hospital where, while he treated for some large scratches, he was not treated for rabies exposure because there were no bites.

This isn't too surprising, since it's an area in which there are some education gaps and misconceptions. The main risk for rabies transmission from dogs is from bites, since the virus is present in high levels in saliva, and bites directly inoculate saliva into the body. Rabies contaminated saliva deposited on intact skin isn't a risk.  Rabies virus shouldn't be hanging out on a dogs paws, so it's easy to see how the transmission risk from scratches might be overlooked. However, during an attack, saliva contamination of the skin and a scratch that breaks the skin can both occur, thereby inoculating rabies virus into the body just like a bite.

Presumably that's what happened here, because 2 months after the attack, the boy developed rabies. It started with severe itchiness over the site of the scratch, and he was dead two days later.

We can't play around with rabies. If there's potential that an animal interaction led to rabies exposure:

• The animal must be identified and either euthanized so its brain can be tested, or (if a dog or cat) quarantined for 10 days to ensure that it does not exhibit any signs of rabies.
• If the animal can't be identified and quarantined or tested (or if it's positive for rabies), proper post-exposure treatment is required.

More information about rabies can be found on the Worms & Germs Resources - Pets page.

My typical answer to the question is “Yes, but…” followed by an explanation of the overall low risk. My general line is:

• It can be transmitted to people.
• Human infections are very rare
• There’s no use panicking over MRSP or being draconian when you have an infected animal.
• At the same time, no one wants a highly resistant infection, so some basic measures should be used to reduce the risk of transmission.

Issues are also greater when people with compromised immune systems are involved, and a recent paper highlights this.

The paper (Savini et al, Journal of Clinical Microbiology 2013) describes MRSP infection in a 65-year-old man who was immunocompromised because of a bone marrow transplant. He developed a wound infection, and his physicians and the diagnostic lab did a pretty comprehensive study of the bacterium they isolated from the wound, ultimately determining it to be MRSP.

The man lived “close to a pet dog and farm cows," whatever that means. The dog was probably the source, but unfortunately (as is common) no efforts were made to see if the dog was carrying MRSP, to see if the cows were positive for MRSP (since this bug can rarely be found in cattle), or to type the isolate to see how it compares to strains that are typically found in animals.

Will this report change my answer to the first question? No. It gives me another example of a human MRSP infection, but such events are still exceedingly rare and this individual was highly immunocompromised, having graft-vs-host disease after his bone marrow transplant.

We don’t need to be afraid of MRSP, but we need to realize there is some risk, and the risk is presumably higher for certain people (e.g. very young, very old, people with compromised immune systems). We therefore need to use some basic infection control and hygiene practices to reduce the incidence of transmission of MRSP and other potentially harmful microorganisms from animals to people.

More information about MRSP can be found on the Worms & Germs Resources - Pets page.

Anyway, spring brings with it many things, one of which is hatching chicks. I saw signs for them at a local farm supply store a couple of days ago, and perhaps not coincidentally, this week’s edition of CDC’s Morbidity and Mortality Weekly Reports provides an update on the 2012 human Salmonella outbreak that was linked to contact with chicks and ducklings from a single supplier.

This outbreak has been talked about before, but this report gives some final numbers.

• Ultimately, 195 people infected with the outbreak strain of Salmonella Infantis were identified. (That’s probably a major underestimation too, since in outbreaks like this lots of people get sick but don’t have fecal cultures for Salmonella performed.)
• 33% of affected individuals were children 10 years of age or less.
• 79% of people who got sick reported contact with poultry in the week before illness started.
• Birds were obtained from various feed stores or directly from hatcheries, and 87% of people that provided information about chick or duckling sources reported getting them from a single mail-order hatchery in Ohio.

Chicks and Salmonella go hand-in-hard. Chicks are high-risk for shedding the bacterium, and people can get infected by handling chicks or having contact with their environment. Children are at high risk for infection since they tend to have closer contact with chicks and because they are more susceptible to Salmonella. That’s why it’s recommended that kids less than 5 years of age not have contact with young poultry.  Day cares and kindergartens planning on their annual hatching chick programs… please take note.

The article includes some more recommendations.

• Feed stores should use physical barriers (e.g., a wall or fence) between customers and poultry displays to prevent direct contact with poultry.
• Educational materials warning customers of and advising them on how to reduce the risk for Salmonella infection from live poultry should be distributed with all live poultry purchases

Part of the last point is keeping young kids away from chicks and stressing good hand hygiene practices. Like most things in infection control, a little common sense goes a long way.

They concluded that puppies shouldn't be aged care companions because of "high rates of Campylobacter carriage and shedding, their social immaturity, susceptibility of elderly residents to infection and poor outcomes." Such a conclusion is not really that surprising or novel, actually. The 2008 international guidelines for animal visitation in hospitals recommend that only adult dogs and cats should be used for these activities, for several good reasons:

• Puppies are biohazardous. It's just biology. Young animals are at much greater risk of shedding various bacteria that can cause disease in people, such as Campylobacter.
• Contact with puppies and kittens has been clearly demonstrated as a risk factor for diseases like campylobacteriosis.
• Compared to adult animals, puppies and kittens are more likely to poop on the floor.
• Puppies and kittens are also more likely to nip or scratch through playful behaviour.

This is not to say that everyone should avoid puppies and kittens, after all they are cute and entertaining, and a great pet in many situations. The risk is higher in certain populations, such as people living in nursing homes, and while puppies are fun, similar positive impacts can be obtained by well-run visitation programs using older animals. That's the approach that being taken in Canberra, as trained adult dogs will still be allowed to visit aged care homes (hopefully as part of a structured program).

The latest Worms & Germs info sheet is about rat bite fever. It's available by clicking here, and you can also find it along with all of our other info sheets on the Worms & Germs Resources - Pets page.