Worms & Germs Blog

Clostridium difficile, hospital visitation and dog risk

Posted in Dogs

A reader has been trying to post a question about an older post on C. difficile in visitation dogs. Here’s the question and my answer:

Do the dogs have a risk of getting sick from the C. difficile bacteria?  I understand from the post that they can ingest and shed it in their feces, but the post never states whether they can get sick from the bacteria or not!

It’s a great question, and it lacks a similarly great answer. We don’t really understand C. difficile in dogs. We’ve made an association between the presence of C. difficile toxins in feces and the presence of diarrhea in dogs, but there are a few things that cloud our understanding of whether C. difficile is actually a significant problem. My guess is that C. difficile is a cause of diarrhea in dogs, but it’s not a major one. Or, maybe more accurately, it’s not a common cause of serious disease. It might be a relatively common cause of mild disease that gets better on its own (and therefore just doesn’t get diagnosed), but is an uncommon cause of serious disease. Dogs don’t get recurrent C. difficile infection or pseudomembranous colitis like people do, and those are the two most serious and recognizable forms of disease. Given the commonness of exposure (dogs probably ingest a small number of C. diff spores on a routine basis) and the low apparent incidence of disease (at least serious disease), it doesn’t seem to be a major health risk.

Echinococcus multilocularis: Alberta, Canada

Posted in Dogs, Parasites

Several news articles have been written lately about the recently-described cases of Echinococcus multilocularis infection in four people in Alberta. The cases of alveolar echinococcosis have occurred over the past 4 years, and raise significant concerns.

Echinococcus multilocularis is a small tapeworm but it causes big problems.


  1. It’s a potentially nasty parasitic disease that can act a lot like a tumour.
  2. By the time it’s recognized, treatment can be difficult.
  3. Since the incubation period is 5-15 years, infections identified now developed many years ago, and there are probably other people who are infected and don’t yet know it.
  4. This number of cases, combined with evidence of the parasite in wild canids (foxes, wolves, coyotes) in a couple of regions in southern Canada suggest the parasite is well established in certain parts of the country (besides the arctic) and probably beyond.

Eradication of this parasite isn’t practical in regions where it’s established, since it’s presumably well entrenched in the wildlife population. Its life cycle includes infection of small mammals (mainly rodents), that develop tumour-like lesions in their internal organs (typically liver). When the animal is eaten by a canid, the tapeworm develops in the intestinal tract, where it produces eggs. These eggs are shed in feces and the life cycle continues when another small critter ingests an egg. People can also develop the tumour-like lesions if they inadvertently ingest tapeworm eggs. Dogs can occasionally be infected in this manner too, but more often develop the intestinal infection after eating an infected rodent, and then shed eggs (which then poses a risk to people and other animals).

Here are a couple resources for more information:

Worms & Germs Blog Echinococcus Fact Sheet

Public Health Ontario’s 5 things to know about E. multilocularis

For veterinarians, the Ontario Animal Health Network (OAHN) infographic Emerging Risk: Echinococcus multilocularis in Ontario

Psittacosis in a Pet Store Worker

Posted in Birds

Following up on yesterday’s post about a bird-and-fish-associated infection, this next story also involves a pet bird, but with a much worse outcome. It involves a young woman who developed a very serious case of psittacosis linked to her job in a pet store. Psittacosis is a bacterial disease caused by Chlamydophila psittaci, a bacterium that is linked mainly to psittacine birds (i.e. birds in the parrot family), and it’s one that is easy to overlook if bird contact isn’t considered.

The woman sued the pet store where she worked and the associated companies, receiving a multi-million dollar settlement to help compensate for her for the devastating complications of infection, including brain damage. The lawsuit alleged that she contracted the infection from a cockatiel that the store purchased. It’s not clear how/if that was confirmed, but it’s a reasonable source.

Importantly, the focus of the claim isn’t that she was exposed to C. psittaci. Rather, it’s that she had received no health and safety training for her job. That’s an important distinction because there is an ever-present risk of zoonotic pathogen exposure when there’s contact with animals. Whether it’s a personal pet, petting zoo or job in a pet store (or vet clinic), exposure is always a risk. The key is the need for people to know the risk and what they can do to reduce the risk. If a workers (or pet owners) have this information, they can make an informed decision about whether or not they are willing to accept that risk. If they are not educated and trained, they can’t. The pet store can’t be the one deciding whether an employee is willing to accept the risk. The employee has to do that, after being given the tools to do so. Too often, education is lacking, whether it’s a pet store employee, petting zoo visitor or pet owner. That’s what more lawsuits are focusing on, and cases like this should highlight the importance of education and training.

Another component of this case that wasn’t discussed in the article is the medical care the plaintiff received . Psittacosis can be severe but is also treatable, especially if caught early. As has been a common theme on this blog, obtaining animal contact history is a key aspect of successful treatment of zoonotic diseases, but unfortunately one that’s rarely done right.

A Bird, Some Fish and a Near Amputation: Bizarre Headline but an Important Story

Posted in Birds

Why is it that zoonotic disease case reports in the scientific literature sometimes get titles that are…well, let’s just say “creative.”

A recent example of a strange headline for an interesting case report is “The Brief Case: A Fishy Tale Prevents Digital Doom following Polly’s Peck—the Importance of Pets in a Comprehensive Medical History” published in the Journal of Clinical Microbiology (Simpson et al. 2017).

I guess it’s a double zoonosis, as the infection described was linked to both a bird and fish. Birds are more commonly implicated in zoonotic infections but fish-tank associated infections occur, usually by the bug implicated in this report.

Here’s the short version of the story:

  • A 68-year-old man was bitten by his pet African Grey parrot. He’d be in a high risk category for infections based on his age, as well as his medical history. He went to a physician the day after the bite and was given oral antibiotics because of inflammation at the site of the bite. Swelling persisted and some further testing (a couple of months later) showed likely infection of the bone.
  • Over a year later, he went back to his doctor with worsening finger swelling, and the next month a rheumatologist injected one of the finger joints with steroids to reduce inflammation. The problem is, steroids reduce inflammation by suppressing the immune response, and when there’s an infection present, suppressing the body’s response often leads to badness. Consistent with that, things had worsened by the next month, more aggressive care was needed, and amputation was considered.
  • Eventually (a long time later), a diagnosis of Mycobacterium marinum infection was made. This bacterium is associated with fish and fish tanks, and infection is often referred to as “fish tank granuloma.” The parrot bite set the scene for infection by damaging the skin and allowing the bacterium to access the site. The person’s age and health status reduced the ability to eliminate the bacterium, and the steroid injection blew things wide open.
  • Fortunately, over many months of treatment, he responded and full function of the finger was regained.

An important part of this story is the statement that “A comprehensive medical history revealed that, in addition to the African gray parrot, the patient kept tropical fish and had cleaned the fish tank thoroughly following the parrot bite.”  This only came out over a year after the onset of disease, when an infectious disease team was involved. It’s a common theme on this blog, but while pet-associated infections are uncommon, getting pet contact history when infection does occur is critical and unfortunately rare. Here, as in countless other cases, failure to get that information was a key part of the pathway that lead to complicated and prolonged disease.

As is stated in the paper, “Pet ownership is an often neglected part of a medical history with both patients and health care professionals sometimes being unaware of the potential risks of zoonotic diseases. In this case, eliciting multiple pet ownership—after an 18-month diagnostic delay— contributed to saving this gentleman’s M. marinum-infected finger from amputation”.

Dog Bite Near-Death: A Cascade of Missed Opportunities

Posted in Dogs

warning-dogA few sentences into a Washington Post article entitled “A dog bite sent him to the ER. A cascade of missteps nearly killed him”, I was thinking, “This sounds like a pretty typical Capnocytophaga canimorsus infection. I wonder if this guy lost his spleen earlier in life.”

It turns out that was true. Unfortunately, neither the person with the infection nor the initial healthcare providers had the same thought. It almost cost him his life, and we need improvement on both sides.

The scenario is pretty typical for infections caused by this bacterium, which is found in the mouths of most (or all) dogs. Rarely does it cause disease.  People without spleens are actually the highest risk group, but they often don’t consider themselves immunocompromised.

The affected person in this case had been bitten by a neighbour’s dog 3 days before he got sick. The wound was washed out, and he went to an urgent care clinic the next day. He got a tetanus shot, and while the doctor offered antibiotics, he decided to forgo them.

The next day, his condition started to go downhill, and it progressed to the point where it wasn’t clear whether he would survive. Fortunately, he did pull through, ending up with profound hearing loss and amputation of a few toes. However, even though those are significant issues, he’s lucky. Most people die. Those who survive often lose multiple limbs or have other severe consequences.

This scenario shows a cascade of inadequate education and missed opportunities that ultimately could have cost him his life. At various points in the process, there were opportunities for intervention by both the patient’s family and the healthcare team.

1. Time of splenectomy

People who have their spleens removed need clear counseling that their immune system is compromised. As part of that, they need to know that if they are ever bitten by a dog, they must get antibiotics.

2. Time of dog bite

Good wound care, as was done here, is critical, but it’s also important for the person to see a doctor, to tell the doctor they don’t have a spleen, and to make sure they get antibiotics.

3. Doctor visit

Any evaluation of a person bitten by a dog should include a question about immunocompromise, and specifically if the person has lost their spleen. If the answer is yes, they must get antibiotics.

4. Hospital admission

The bite needs to mentioned initially (and repeatedly). It’s an abnormal event that preceded an abnormal medical situation. That doesn’t mean it’s always the cause, but it needs to be noted. Here, the bite wasn’t mentioned at the start.

Healthcare personnel also need to be notified that the person has no spleen. Since universal electronic medical records aren’t available, hospital personnel don’t have access to everyone’s full medical history on admission. This is a critical piece of the puzzle for a case like this.

We’ll never know, but if the patient in this case had been started on antibiotics at that first visit (or on the day of the bite, ideally), it’s likely that none of this cascade would have happened.

More information about Capnocytophaga can be found on the Worms & Germs Resources – Pets page.

Things Not To Do With Raccoons

Posted in Parasites, Rabies

1) Pick up baby raccoons and take them away

  • Raccoon litter JVGRarely does this end well. It’s illegal in many areas (including Ontario). Raccoons don’t do well long-term in households for various reasons (their curious and destructive nature being a big one). And, they are potential sources of a number of zoonotic diseases (rabies being a big one but not the only concern).

2) Take them to a bar

  • This could be simplified to “take them anywhere.” The more people encounter the raccoon, the more people might be exposed to the pathogens it carries.

Seems like common sense, and yet people picking up cute raccoon kits and taking them somewhere (though not necessarily a bar) seems to happen all the time. A recent incident in Pendletown, NY, highlights the issues. A woman picked up a baby raccoon from a litter of 13 and took it to Mr. Quiggley’s Dead Dog Saloon, where it interacted with multiple people.  Because raccoons are rabies reservoirs, the raccoon had to be euthanized for testing. The rest of the litter was also tracked down and euthanized for testing, apparently, but that doesn’t make a lot of sense to me. If the raccoon to which people were exposed could be tested, that provides all the information that is needed from a rabies exposure standpoint. Maybe there was concern that other people would pick them up or maybe she put the baby back in with the litter after it’s trip to the bar and no one could tell which one it was. Regardless, the raccoons probably didn’t have rabies but the person’s actions led to their deaths.

Beyond rabies, there are a few other potential concerns:

  • Baylisascaris procyonis: The raccoon roundworm is very common, and it’s likely that eggs of this parasite were being shed in feces, or that the haircoat of the raccoon was contaminated with feces containing the eggs. The latter is the main concern because eggs that have been in the environment are the ones that can infect people. Infection in people is rare, but the parasite can cause very nasty neurological disease so it’s one to be aware of.
  • Leptospirosis: Raccoons are a host of Leptospira bacteria, which are shed in urine. Contact with urine isn’t uncommon when handling young animals, and urine that gets into cuts or the eyes, mouth or nose can result in transmission.

Hopefully not many people actually handled the critter and they washed their hands (but sometimes common sense is surprisingly uncommon).

Take home message: Leave wildlife in the wild.

Lyme disease: The Difference Between Knowing and Actually Doing…

Posted in Dogs, Horses

Lifetime LymeGuest blog by Dr. Michelle Evason, DVM DipACVIM (as well as current PhD student and coordinator of our Lifetime Lyme Study)

In 2014, the Public Health Agency of Canada (PHAC) initiated a 3-year marketing campaign (news, advertisements, social media, collaboration with Parks Canada to post signage, etc.) to try to raise the general public’s awareness and educate them on the topic of Lyme disease. This (Lyme) isn’t exactly a low profile subject… and it’s become increasingly high profile in the past several years. Particularly in Canada, where ticks appear to be giving raccoons a solid run for the title of top non-human vector of disease causing pathogens.

Interestingly (and fairly forward thinking in my opinion), two studies (see below) were performed to look at the level of Lyme awareness in canucks and secondarily to assess whether PHAC’s targeted educational media blitz had any effect on understanding of Lyme disease and subsequent behavior changes regarding tick prevention. I suspect the study group was hopeful things would indeed improve and it would be considered dollars well spent… although some of us tend to be cynics about that sort of thing (and yes, that is my idea of subtle foreshadowing). Cutting to the chase… a bit strangely (and sadly) Canadian respondents’ correct answers for prevention or reduction of tick attachment, i.e. avoiding wooded areas or mowing one’s lawn regularly, appeared to decrease over the course of the media campaign. In other words, there were more correct survey answers before the educational intervention than after the 3 years of media coverage. Also (again a bit depressingly), questionnaire respondents tended to answer incorrectly more often if they lived in a Lyme “higher risk” zone or location.

Fortunately (maybe?) most Canadians who participated in the studies appeared to know about Lyme disease and also what medical symptoms are associated with illness. So, the “raise awareness” box did appear to get checked – which is wonderful. However…this didn’t appear to translate into knowledge regarding how to protect oneself from actually getting Lyme disease, such as regular tick checks, wearing protective clothing or using tick repellent.

I’ve never understood why knowing something doesn’t translate into actively doing something about it. Granted I have developed a few theories over the years, and I’m positive my family would be pretty quick to say that I don’t always make the best choices even when I know better also, so glass houses and all that. On the other hand, Lyme disease gets an awful LOT of attention, and it seems like focusing some of that energy on preventing it from happening might be good? And I suspect that would be true for all animals at risk, not just the ones who bark or whinny most believably.

Aenishaenslin, C., Bouchard, C., Koffi, J. K., Pelcat, Y., & Ogden, N. H. (2016). Evidence of rapid changes in Lyme disease awareness in Canada. Ticks and Tick-Borne Diseases. http://doi.org/10.1016/j.ttbdis.2016.09.007

Aenishaenslin, C., Bouchard, C., Koffi, J. K., & Ogden, N. H. (2016). Exposure and preventive behaviours toward ticks and Lyme disease in Canada: results from a first national survey. http://doi.org/10.1016/j.ttbdis.2016.10.006

A Perfect Storm for Canine Flu

Posted in Dogs, Other diseases

rough collieThere were several more reports over the weekend in follow up to the canine influenza outbreak at dog shows in Florida early last week.  Unfortunately, but not surprisingly, associated cases were then found in North Carolina, and have now been reported in 11 states, no doubt  from dogs that were at the shows in Florida (and Georgia) and unwittingly brought the H3N2 canine influenza virus (CIV) home and spread it to local dogs.  Two deaths were even reported in North Carolina, but details were not provided so it’s difficult to determine exactly what role influenza may have played in these outcomes (i.e. these dogs could have had other complicating conditions resulting in more severe disease).

So the question now being asked is, what should dog owners do if they had plans to take their dogs to shows in the affected states, or anywhere else for that matter?

If owners want to go to such events, they have to accept that there is increased risk that their dog(s) could get sick.  Period.  But that actually applies to any canine group setting, anytime, anywhere, and CIVs is not the only infectious disease risk.  If they’re really worried about CIV then they probably shouldn’t go at all, but they should probably also never take their dogs to the dog park either in that case, because there are similar risks.  However, if attending a dog show or other group event there are some measures that can be taken to reduce the risk of infection.  One way to think about it is that dog flu is spread very much like human flu, so strategies to avoid it are very similar as well, such as:

  • Don’t let your dog have close contact with unknown dogs, especially dogs that are sneezing, coughing or otherwise sick (but remember that healthy dogs can shed CIV as well if they’re either incubating or recovering).
  • Don’t share food/water bowls, toys, blankets or grooming supplies with other dogs, as these items could be fomites for pathogens.  Washing or laundering such items can also help decrease contamination (especially, for example, upon returning home (or better yet, just before leaving the event)).
  • People can also be a fomite, so it’s important for the owners to pay careful attention to hand hygiene (e.g. use hand sanitizer often), especially if they  handle/touch other dogs, in order to avoid transferring pathogens to their own dog(s).
  • Vaccine is definitely worth considering, but this should be a discussion between veterinarian and owner in advance.  The CIV vaccine is certainly not perfect, and it does have its shortcomings (just like human flu vaccine), but it can still help and the risk associated with vaccination is otherwise low.  Dog(s) attending shows and other events should definitely by up-to-date on all their core vaccines as well (including rabies!).

Not all areas (in the US or otherwise) are the same risk for CIV.  Outbreaks tend to be localized, but as just demonstrated by the consequences of the Florida dog shows, outbreaks can very rapidly spread to other areas with the movement of dogs.  Owners should contact the organizers of the specific show to ask what the situation is in the area.  If there is an increased risk of CIV, the show organizers would ideally be alerting attendees and taking additional precautions at the show to decrease the risk of transmission (e.g. increased cleaning and disinfection protocols, management of participants to limit mixing of dogs, etc), assuming they decide that “the show must go on” despite the risk.

There is an excellent technical paper on risk reduction strategies at canine group events that was published last year (Stull et al, JAVMA 2016).  It is geared more toward organizers of such events, but would also be a good reference for veterinarians that may be involved in some way.  It covers infectious disease risks in general, including but not limited to CIV.

The other important thing to remember is that in most young, healthy dogs (hopefully most show dogs fit in this group) disease from CIV is relatively mild and resolves without complications, so even a dog did get sick, it usually just means giving the animal some down time at home and ensuring it does not come in contact with other dogs during the risk period for shedding (which could be a few weeks).  In reality, any time owners return with a dog from a show (especially outside of their local area), that dog should be kept separate from other dogs (both on and off the property) in case they picked something up but have not yet developed signs.  A couple of weeks would be ideal, but even a few days or a week (especially for CIV, which has a relatively short incubation period) would be better than nothing.

With canine flu, as for any infectious disease, there are always different factors that increase or decrease the risk of infection in a given situation, some of which we can control to some degree, and others which we can’t.  The key is to find the balance so that group events can still take place, but the risk is reduced to an acceptable level for the participants.  As several of the articles about this outbreak have mentioned, now is not a time to panic, but it is a time to take precautions.

New Methicillin-Resistant Staph Veterinary Dermatology Guidelines

Posted in Cats, Dogs

green-germA new Clinical Consensus Guideline, coordinated through the World Association for Veterinary Dermatology, has been released: Recommendations for approaches to methicillin-resistant staphylococcal infections of small animals: diagnosis, therapeutic considerations and preventative measures. Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

This large and comprehensive document is open access and can also be downloaded via the Veterinary Dermatology website as well as through the link above.

H3N2 Canine Flu in Florida

Posted in Cats, Dogs, Vaccination

The recent H3N2 canine flu outbreak centred around dog shows in Florida has led to the usual round of questions and concerns.

How many dogs have been affected?

  • 3 dogs at parkHard to say. Cases aren’t carefully tracked and it is reasonable to assume that the majority of dogs that developed influenza (especially mild disease) were never diagnosed. Testing costs money and often doesn’t change how a dog with respiratory disease is managed, especially in the midst of an outbreak where influenza is assumed to be the cause. Therefore, a lot of cases get presumptively diagnosed but not confirmed. We keep working on ways to better track diseases like this but getting uptake is a challenge.

Is this a sign of a new problem?

  • No. Canine flu has been around for a while, although H3N2 canine flu is a relatively new arrival to the US. The virus causes sporadic larger-scale problems (like this outbreak), but then tends to retreat back to being a low-level disease. Outbreaks are always possible with a flu virus when it gets into a dog population with lots of close contact and limited immunity (not previously exposed or not vaccinated). A dog show is a great mixing vessel for viruses like influenza. All it takes is one infectious dog to cause an outbreak that can spread rapidly, as opposed to an infected household dog that has far fewer opportunities to infect other dogs during the relatively short infectious period.

Should my dog be vaccinated?

  • There’s rarely a yes/no answer to this question. Vaccination decisions should be based on a risk assessment, considering the likelihood that your dog will be exposed and the implications of infection. Things that increase the risk/need would include:
  1. Known presence of circulating canine flu in the area.
  2. Planned travel to an area where canine flu is present.
  3. Regular or upcoming interaction with lots of different dogs.
  4. Regular or upcoming interaction with dogs from areas where canine flu may be present.
  5. Dogs that are at increased risk of complications following infection.
  • This last factor is something I think is often overlooked (and we don’t have a lot of data to go on). Influenza infection is usually relatively benign, but it can be serious. In humans, we know that certain groups are at increased risk of complications. The same presumably applies to dogs, although it’s less well defined. For me, I get concerned about dogs with underlying heart and respiratory tract disease that might not tolerate infection well. I’m also concerned about elderly dogs and dogs with diseases that compromise their immune systems. These are groups of dogs that probably also have fairly low vaccination coverage rates in general.

What should I do if I live in an area where canine flu is present?

  • Know what’s happening, as much as you can. If an outbreak is largely confined to show dogs, average pet dogs are at lower risk, but show dogs may still interact with pet dogs at parks and other areas. If there are anecdotal reports of dogs getting sick from parks or other routine contacts, that’s useful to know (even though you have to take those types of reports with a grain of salt).
  • If there is known flu activity in the area (or vague reports of coughing dogs without a diagnosis), consider keeping you dog away from other dogs for a while. Influenza usually burns through a population fairly quickly, so we’re talking about days rather than weeks, in most situations. The less dog-dog contact, the less risk of flu spreading. To maintain an outbreak, the average dog with flu must encounter and infect another susceptible dog during the fairly short time it is shedding the virus.
  • If your dog develops signs consistent with influenza (e.g. cough, runny nose and eyes, lethargy, decreased appetite), keep it at home and away from other dogs. If you need to take it to the vet, call ahead so they can make a plan to prevent exposure of other dogs (e.g. examine your pet outside, bring it right into an exam room or isolation to prevent it from mixing with other patients).
  • Talk to your vet about vaccination.

What should I do if I live in an area where canine flu is not present?

  • Pretty much the same list as above. “Not present” really means “Not present at the moment” or “Not known to be present,” since any dog you pass on the street could potentially be infected. The risks are obviously much lower in areas where flu activity hasn’t been reported, but disease reporting in dogs is pretty lax.

Can cats be infected?

  • Yes, although it’s much rarer in cats than dogs.

Is there a risk to people?

  • I should say there’s “no risk” since that makes my life easier, but the answer is probably more accurately “there’s virtually no risk.” Infectious diseases like to do odd things ,and while there’s no evidence that H3N2 is a zoonotic disease concern, I can’t say with complete confidence that there’s not a rare subset of people who would be susceptible (usually with mild infection). Most likely, lots of people have been exposed and some have had the virus enter their bodies, where their immune system took care of it with no problems. Rare mild disease may not be occurring or may easily be overlooked. The bigger concern is the potential for a dog or other species to be infected with H3N2 and another flu virus at the same time, creating a new virus that could be more virulent in people. This is always a concern, but the odds of this happening are very low. The fact that it’s past peak human flu season probably helps too, reducing the odds of a co-infection.