I’ve written a lot about raw pet food in the past. Initially, the concerns were about Salmonella, since raw fed dogs and cats have high rates of shedding Salmonella, can get sick from it and owners can be infected (from the pet or cross-contamination from the food…always hard to sort that out).

More recently, I’ve been concerned about multidrug resistant E. coli and related bacteria. I think this may be a much bigger but insidious risk. Eating a raw diet has been shown in a few studies to be a major risk factor for fecal shedding of highly antibiotic resistant bacteria, particularly extended spectrum beta-lactamase (ESBL) producing bugs.

Yet, there are various other issues. A recent paper in the journal Epidemiology and Infection (Kaindama et al) describes a cluster of human E. coli O157 infections in the UK that was linked to raw pet food. This strain of E. coli can cause serious illness in people, including hemolytic uremic syndrome, which can be fatal. The bacterium can be found in the gut of food animals (mainly cattle) and can therefore sometimes contaminate meat.

In this cluster, 4 people infected by a similar strain of E. coli O157 were identified.

  • They got sick within a one-month period in 2017.
  • I’m guessing three were 6 year old kids, based on the median and age range provided in the paper. The burden of zoonotic diseases often falls disproportionately on kids.
  • Three of them were hospitalized, and one died.

During the investigation, no typical sources of E. coli O157 exposure were identified. The only commonality between cases was all had contact with dogs and a history of consuming raw carrots. Three of affected people had been exposed to dogs fed a raw meat diet, two of which had received tripe from the same supplier. The other person’s dog was not fed a raw meat diet but had contact with another dog that was fed raw meat.

E. coli O157 was subsequently found in raw pet food samples from the affected households. However, different strains were found. That’s not too surprising since contamination will be variable and testing would have occurred well after the food that likely caused the infection was fed. One batch might be contaminated, the next not and the next contaminated with a strain from a different origin. Finding different strains doesn’t round out the story as nicely but it maybe highlights more concern. This wasn’t a one-time point exposure because of some strange event. Contamination of raw pet food with this concerning bacterium might be more common than has been recognized.

Whether these are rare cases or the small subset of diagnosed cases is unclear. This was identified because:

  • It was a cluster of infections
  • Public Health England does detailed whole genome sequence testing of E. coli O157 isolates
  • They have detailed case questionnaires
  • They looked for and found a link

Large outbreaks of disease in people involving the same E. coli O157 strain wouldn’t be expected from exposure to dogs fed diets where there’s probably a lot of small batches and batch-to-batch variation. Patterns need to be apparent to flag a potential problem, and sporadic cases aren’t as amenable to that. So, we don’t know if this was an exceptional event (i.e., infections are rare) or whether this was a matter of the right circumstances allowing for rare diagnosis of a more common problem.

My personal opinion here is based on seeing enough sick pets and people from raw diets. I don’t like to see them fed. That’s particularly true in households with people or animals that are at higher risk of severe disease (young, old, pregnant, immunocompromised). There are ways to reduce the risk, both in terms of products that are purchased (e.g. high pressure pasteurization likely reduces the risk a lot but doesn’t eliminate it) and how raw diets are handled. More information about feeding raw diets and reducing the risk is available in our Resources section.

The Canadian Food Inspection Agency (CFIA) has released new rules for importation of dogs less than 8 months of age for commercial purposes into Canada. The issues around canine importation have been increasingly prominent in recent years, and came to the forefront following an importation debacle in June 2020 that led to the deaths of dozens of dogs imported as part of a shipment from Ukraine last year.

The new rules are a good step. They don’t fix all the issues, they don’t address all imported dogs, and don’t seem to beef up penalties, but they should result in some improvements and hopefully a greater ability to get data about at least some of the dogs being brought into Canada every year.  The rules (for now) only apply to dogs under 8 months of age being imported for “commercial” purposes, including breeding, showing and most importantly sale/adoption. Although this is just a subset of all imported dogs, it’s a big one, as it includes commercially imported puppies like the shipment from the Ukraine last year.

Here is a summary of the main changes (you can also check out the “then and now” table from the CFIA for a side-by-side comparison with the old rules):

No more unlimited “multiple entry” import permits.

  • Previously, you could get a permit for multiple batches of dogs of undetermined sizes over a period of time. Now, you can only get single entry permits for a specific number of dogs.

Stricter rabies vaccination requirements.

  • Dogs must be vaccinated at least 28 days before shipping (previously there was no waiting period between vaccinating and importing a dog).
  • Since rabies vaccine can’t be given until 12 weeks of age according to label instructions, dogs will now have to be at least 4 months old before being shipped (although it doesn’t solve the problem of importers lying about the age of the dogs in a shipment…)

Mandatory treatment for internal and external parasites before departure.

  • That’s a good general practice for a number of reasons, so it’s great that it is now a requirement. Among other things, it helps reduce the risk of importing parasites along with the dogs, including foreign ticks or tickborne diseases. I haven’t seen the specific details yet, but the drugs used and timing of treatment relative to shipping will impact how useful this is.

Provisions for quarantine when needed.

  • We don’t have federal quarantine facilities and there was no provision for this before. Now, importers have to have an arrangement with a facility to quarantine imported dogs, if needed.
  • When quarantine will be required isn’t clearly defined, but if an issue is identified at arrival, it provides a mechanism to get the dogs quarantined and treated if necessary (at the importer’s expense) while the issues are assessed and resolved.
  • Notably, this only applies to dogs imported by air.

More organization required prior to arrival of the dogs.

  • Rather than just showing up at the border unannounced, shipments must be scheduled in advance to ensure adequate staff are available for inspecting the dogs on arrival.

Clearer rules around the kennel of origin.

  • The kennel where the dogs came from must be certified by an official vet of that country, indicating the kennel meets certain criteria specified by the CFIA.
  • This new rule still has a lot of potential loopholes and potential for corruption (e.g. if the dogs are transferred to a temporary facility before shipment, does that then become the kennel of origin?).  At least it’s an improvement on the previous rule and a step in the right direction.

Overall, I’d say the new rules are a good start, but let’s hope they don’t stop there. These changes won’t fix all the problems, but they should help.

The biggest issue that remains: Canadian consumers.

There would be no mass importation of poorly raised puppy mill dogs if people weren’t willing to put on blinders, avoid asking questions and pay thousands of dollars for a dog from a questionable source.

Ivermectin is a commonly used anti-parasitic in animals, and it’s also used in people to treat some parasitic diseases. Additionally, it’s still widely discussed in some internet circles for treatment or prevention of COVID-19. That’s based on mainly anecdotes, some in vitro study, and very poor quality “clinical trials”.

It’s led to stories of people using or even hoarding veterinary ivermectin products. I’ve had lots of questions from the general public and veterinarians as a result (including stories of people buying more heartworm meds for their dog  than they’d ever need).

Bad idea. Here are some reasons why:

  1. There no evidence that it works. An in vitro study showed ivermectin inhibited SARS-CoV-2, but only at massive doses, well beyond what would be safe for use in people.
  2. Anecdotes aren’t data.
    • I don’t dismiss clinical observation, as it is the starting point of many important discoveries. However, a lot of things I have thought I observed or initially appeared to “work” didn’t pan out to be true over time.
    • Observations should lead us to take specific steps to figure out if something is real.  They help raise questions, not answer them.
  3. Other factors may be involved that make the drug appear effective in some siutations, but those factors don’t apply broadly.
    • One potential reason ivermectin may seem to work in some areas is because it’s an anti-parasitic. Strongyloides stercoralis is a human respiratory parasite that is common in some countries. People get infected and the parasite can lay dormant in the body, but when they are immunosuppressed, it can be re-activated.
    • Dexamethasone is a common and effective treatment in people with moderate to severe signs of COVID-19.  It reduces inflammation, but also impacts the function of the immune system (since that’s what triggers inflammation).
    • If someone is infected with dormant Strongyloides stercoralis, dexamethasone treatment for COVID-19 might lead to re-activation of the parasite, and that would complicate respiratory disease.
    • I don’t dismiss that potential, but it would mean that ivermectin might be effective in people with dormant Strongyloides stercoralis infection that are also receiving dexamethasone.
    • That’s a lot different than “ivermectin works against SARS-CoV-2 and everyone, everywhere, who is infected should be on it.”  They should not.
  4. Ivermectin isn’t a very commonly used drug in people, but it is important for treatment of certain parasitic infections.
    • Diversion of the relatively small amount of human ivermectin products towards unnecessary use compromises the care of people that really need it. (I realize that isn’t associated with “don’t steal Fido’s stash” but it’s still an important point.)
  5. Your dog’s heartworm preventative is a low dose treatment.
    • To get the levels used in the aforementioned in vitro study, a person would require a dose of  about 3500 ug/kg. Heartworm prevention in dogs is dosed at about 6 ug/kg.
    • So, my dog Merlin gets one 272 ug chewable a month. To get 3500 ug/kg, I’d need 965 tablets per dose. If I had a small dog, I’d need even more of his supply.
    • If I wanted to self-treat for Strongyloides stercoralis (not sure why I would, but let’s pretend), I’d need 52 of my dog’s chewables – per day.
  6. Ivermectin also comes in more concentrated oral, injectable (don’t even think about it) and pour-on (topical) forms. While I have good confidence in mainstream veterinary pharmaceutical companies, I still don’t want people taking a product that is only intended for (studied in and approved for) use in animals.

Ivermectin is one of many so-called “miracle cures” that we’ve seen pushed on the internet. Like most others, there’s limited substance to the stories behind it. There’s no magic bullet for COVID-19. I’d love it if ivermectin was one, as it’s a drug we know how to use and how to produce. Production could be ramped up and it’s relatively cheap. While conspiracy theories abound, no one has come up with any plausible explanation why an effective drug would be suppressed. Dexamethasone is cheap, widely used and widely produced, and it’s standard of care for some patients. That’s because it works. Ivermectin fits all of those except the “works for COVID-19” which is the most important one.

I’ve had a blog writing dry spell lately (too much other stuff to catch up on), so I’ll jump back with a quick summary of some recent papers on SARS-CoV-2 in animals. There isn’t really anything surprising here, but it’s a continuation of what we’ve been learning and saying for a while.

SARS-CoV-2 infection in cats and dogs on affected mink farms, the Netherlands

We have various concerns related to SARS-CoV-2 outbreaks on mink farms. One is the potential for spread to other animal species, with further risk of transmission, the potential evolution of virus mutants, and possible establishment of a virus reservoir, especially among wildlife.

This study tested a few different groups of companion animals, including 44 stray cats on infected mink farms. Ten of the cats had SARS-CoV-2 antibodies (seropositive), indicating previous infection. The single dog that was tested was also seropositive. This is consistent with other data that the virus can spread beyond mink on infected farms. The risk that poses for further transmission back to people or to other animals is unclear, but it’s a reminder of why we really need to keep this virus out of large susceptible animal populations like mink.

They also tested 500 feline and 500 canine serum samples that were submitted to their diagnostic lab for routine testing.  Two cats (0.4%) and 1 dog (0.2%) were positive for antibodies. Since we don’t know anything about whether those pets were exposed to anyone with COVID-19, it’s hard to put those results into perspective.

SARS-CoV-2 in pets from COVID-19+ households in Utah and Wisconsin

This pre-print describes a study involving 37 dogs and 19 cats from 41 households where a person had COVID-19.

  • No active infections were identified in the pets by PCR.
  • Four cats and 4 dogs had antibodies to SARS-CoV-2, indicating they had been infected. That’s consistent with our ongoing surveillance, in that it’s easy to miss the active infection based on timing of sampling but previous infection can be detect retrospectively based on antibodies.
  • They also reported that of 14 pets that had limited contact with infected people after the person’s diagnosis, none of them became seropositive, compared to 4 of 19 (21%) pets that had ongoing contact with an infected person. That’s not surprising, and supports our messaging to limit contact with animals as much as possible when COVID-19 is suspected in a person.

Role of SARS-CoV-2 infection in pets with severe disease

It has been a challenge in a small number of cases to figure out if an animal got very sick or died from SARS-CoV-2 infection, or whether infection was just incidental.  A pre-print from the US CDC describes an investigation of 5 cats and 5 dogs that died while they were infected with the virus.

  • In one cat with severe respiratory disease, examination of the cat’s tissues and lack of other potential causes of illness suggested that SARS-CoV-2 was the primary cause of disease and ultimately euthanasia.
  • In one dog, it was suspected that SARS-CoV-2 infection exacerbated the animal’s underlying severe and chronic respiratory disease and likely contributed to its illness.

So, in those two cases, SARS-CoV-2 likely caused or contributed to the animal’s death.

  • In the other 8, infection was deemed incidental (although in a couple of the cases, I think an argument could be made that infection may have worsened an underlying problem – it’s hard to say).

This information is consistent with what we’ve already been saying: Infection of cats and dogs isn’t rare, but severe disease is. It’s possible, but not a common outcome.

More on infection and heart disease in cats

I wrote earlier about how we need to be careful interpreting a pre-print suggesting the B.1.1.7 SARS-CoV-2 variant was linked to myocarditis in cats.  This new pre-print describes a single case report of hypertrophic cardiomyopathy (HCM) in an infected cat.  Note that HCM is not uncommon in cats.

  • A person in the household was diagnosed with COVID-19 about a week before the cat got sick.
  • The cat was euthanized and testing identified a thickened heart muscle, consistent with HCM.
  • SARS-CoV-2 virus was detected in various tissue samples, including the heart.  That supports that the cat was truly infected at the time of death.
  • There were clear signs of respiratory infection, which isn’t surprising since SARS-CoV-2 is a respiratory virus. Whether that means it caused heart disease or exacerbated it is the bigger question.
  • There was evidence of inflammation in the heart tissue, which raises concern that the virus was at least contributing to the heart disease.

Overall, it’s quite possible that SARS-CoV-2 infection exacerbated this cat’s underlying heart disease to the point that it required euthanasia. That would be consistent with the pre-print described above about rare cases of severe disease in already-compromised dogs and cats. It’s relevant because it shows that while most of the time infection is mild or inapparent, severe disease can happen, and it’s probably more likely to occur in dogs and cats with pre-existing heart or lung disease. People shouldn’t get too worried because we’ve probably had hundreds of thousands of infected pets (or more, since we’ve had millions of infected people) and only very rare reports of severe outcomes.

We’ve once again updated the Guide to Mitigating the Risk of Infection in Veterinary Practices During the COVID-19 Pandemic (14-Apr-2021).  It can also be accessed through the Ontario Veterinary Medical Association Coronavirus FAQ webpage (member login required).

I’ll be happy when we can stop updating these guidelines. Progress is good and adding new information is useful. I just long for the day when we don’t need them.

Previous versions of the guidance and other related documents can be found on the Worms & Germs COVID-19 Veterinary Resources page.

I’ve taken a look back at some posts from the start of the COVID-19 pandemic, to see how my thoughts have evolved, what I got right and what I screwed up. We have a lot of COVID-19 posts (starting from when we called it “novel coronavirus” or “Wuhan coronavirus” before the SARS-CoV-2 terminology existed). Here are some highlights and “grading” of my comments from a selection of posts

January 20, 2020 “New coronavirus: Companion animal concerns?”: Very early on I said While this virus still seems to be less transmissible and less virulent than its relative, the SARS coronavirus, it’s pretty early to have a lot of confidence in that.

  • Grade B: It turns out SARS-CoV-2 is not less transmissible than the first SARS virus, but I guess I covered myself by saying it was early to have much confidence.

For containment measures for SARS, this new coronavirus or any other new disease, we need to assume that multiple species can be affected until proven otherwise, and we need to act accordingly. That doesn’t necessarily need to be complex. It might just be making sure animal contact questions are asked along with human contact questions, that quarantine protocols consider what to do with exposed animals, and that quarantined individuals are kept away from animals. 

  • Grade A: This turned out to be a fairly accurate statement, but fortunately risks from animals seem to be pretty limited (let’s hope this statement holds up). This is also around the time I sent some (essentially ignored) emails to try to get some consideration of animal aspects in any human exposure response planning here in Ontario.

January 23, 2020 “Novel coronavirus in China… Hold off on blaming snakes”:  In a post talking about how snakes might be the source of SARS-CoV-2, I wasn’t convinced and said I’m sure we’ll see much more genetic analysis of this virus by many different groups, but I suspect it will keep coming back to bats as the source. 

  • Grade A:  A final answer is still needed but this seems correct.

February 5, 2020 “Novel coronavirus and animals”: In talking about whether there’s actually a problem with companion animals, I said we need to focus on ensuring exposed animals are quarantined, using good old fashioned infection control like hand washing, keeping fear at bay and applying logic to the problem.

  • Grade B+: I’ll dock myself some marks on this one since it was focused on dogs. To be fair, the post was about concerns regarding over-reaction and euthanasia or abandonment of dogs, but it didn’t get into the bigger risks we now know are present with other species.

February 14, 2020 “More on COVID-19 (novel coronavirus) in animals”: I said We still have no evidence that this virus affects domestic animals, but since we also still have no real evidence that it doesn’t, it’s best to continue to take reasonable precautions to reduce the risk of exposure of animals to infected people, and to properly manage pets of people who are infected. “

  • Grade A+: Especially since it was at the same time groups like the US CDC were actively pushing back against there being any risk to/from animals.

February 18, 2020 “COVID-19 and potential animal hosts”: This post talked about a study that predicts species susceptibility based on ACE2 receptors. The potential susceptibility of cats is obviously a concern given their commonness as pets and the close interaction many people have with their cats. Pigs could be an even worse issue. If pigs could be infected and shed the virus, and it got into the commercial pig population, it would potentially be an even worse issue.  As with SARS, mice and rats are likely resistant to infection – that’s good from the standpoint of them not being reservoirs in the wild, but it also means they can’t be used for experimental study (as these are the most common lab animal species).

  • Grade C+: I think I over-estimated how useful these studies would be. They were interesting, but some species predicted to be high risk (e.g. pigs) aren’t, and some that were predicted to be lower risk (e.g. cat) most certainly as susceptible to SARS-CoV-2.  I also missed a couple of points. It seems like infection of pigs isn’t a concern but I think I missed some of the main potential concerns, as I wasn’t thinking about them as sources of virus mutants or wildlife exposure.

February 28, 2020 “COVID-19 in a dog”: A post about the first SARS-CoV-2 positive dog: Overall, my concerns are still more about cats. Dogs will probably get investigated more because there are more pet dogs than cats in most regions, and people tend to seek healthcare for the dogs (or alternative caretakers if the owner is indisposed due to illness) quicker than for their cats. 

  • Grade A: That turned out to be true.

March 27, 2020 “Human-to-cat COVID-19 transmission: Belgium”: I said If you’re worried about getting COVID-19, worry about your human contacts, not your pets. Keep pets away from high risk people, but otherwise, your risk is from exposure to people, not your pet

  • Grade A: I haven’t really changed that line in the past year.

March 29, 2020 “Social distancing WITHIN veterinary clinics”: I said Masks can reduce the risk of transmission if someone is unknowingly shedding the virus . Masks aren’t perfect but there can be some benefit. Whether it’s a good use of masks is questionable. Putting on masks for occasional close contact procedures (and ideally reusing that mask for the whole shift) isn’t unreasonable, but whether it’s really worth the mask use is hard to say.

  • Grade D: My line on masking was influenced by influenza data and concerns about mask availability, and I underestimated the usefulness of routine masking. I also focused on it being needed for known close contact situations, not more broadly. Those were the standard recommendations at that time but I still get a “D” for this one.

March 30, 2020 “COVID-19 and ferrets”: Here, I discussed concerns about ferrets.

  • Grade C:  We haven’t seen much SARS-CoV-2 activity in ferrets. Maybe that’s just because they aren’t common pets and don’t get taken to a veterinarian as often. Where I missed the boat was thinking about related species. Mink were not on my radar at all… (see below.)

April 24, 2020 “Pets and COVID-19 fears”: A commentary sent in partnership with the Ontario Veterinary Medical Association to veterinarians to balance awareness and paranoia when talking to pet owners about SARS-CoV-2.

  • Grade A: I’m not sure I’d change anything a year later.

April 26, 2020 “COVID-19 in mink: The Netherlands”: I said We’ll put this in the “interesting but not really surprising” file.

  • Grade C-: Fair statement, but while I talked about the concerns, I don’t think I really appreciated how susceptible mink would be and the issues that would develop from that.

April 28, 2020 “COVID-19 modelling and the impact of releasing cats”: This was a commentary about a crap-tastic paper about releasing infected cats and the potential impact on virus tranmission. Little did I realize this was one of many future “studies” based on little substance, little common sense and a complete abandonment of any principles of peer review. Academic opportunism has abounded in the past year and a bit, with some people putting out utterly useless papers, reviews and commentaries, and sometimes causing harm.

  • No grade… just a rant.

May 28, 2020 “Veterinary clinic staff cohorting”: I said One concept that we’ve recommended for COVID-19 control in veterinary clinics is staff cohorting.

  • Grade D: This turned out to be too impractical in most situations. It might have been useful if this was a short lived problem, but obviously that hasn’t been the case. I dropped this idea pretty quickly.

In the same post Routine cloth mask use whenever a 6-foot gap can’t be maintained between people is emerging as a key infection control tool. Cloth masks are far from perfect, but they can do a good job containing most infectious droplets, which are probably the main source of exposure.

  • Grade C: We now know the focus on the 6-foot distancing as a risk/no risk cutoff isn’t valid. Emphasizing mask use was good, but focusing on known close contact situations wasn’t.

I’d give a higher grade for the rest of the post. Most of it was actually pretty good, but these are some glaring issues.

I’ll pause here to avoid this post getting even longer. Overall, I think we had some pretty good thoughts about animals from the start. I missed the ball on a couple of key things:

  • Importance of masking: I mentioned masking above, but I didn’t realize how much of a core lifestyle component this would be.
  • Duration of the pandemic: I was expecting the pandemic to hit hard in the spring of 2020 based on modelling, so I wasn’t surprised at what we encountered then. However, I didn’t expect the pandemic to drag on this long. I was truly thinking we just needed to hit it hard in the spring of 2020 to return to normalcy in the fall or winter.

As spring approaches, a pressing question has come to the minds of many kids: “Can the Easter bunny get COVID-19?” or “Can Easter bunny eggs spread COVID-19?”

Fortunately, the answer is no. Easter bunnies are safe from this virus and kids don’t have to worry about whatever the Easter bunny leaves behind.

Based on what we know to date, “regular” rabbits aren’t very susceptible to the SARS-CoV-2 virus.  Some types of rabbits can be infected with SARS-CoV-2 experimentally, but they don’t seem to get sick and they only shed low levels of virus. So, even a regular rabbit that was infected probably poses little to no risk.  (Don’t worry kids, no one’s going to try that with the Easter bunny.)

Furthermore, as we all know, the Easter bunnies have inherent magical properties that protect them from various problems (e.g. nosy household dogs). Their elusive nature (have you actually ever seen an Easter bunny depositing its wares?) and strategic placement of gifts in empty rooms mean the Easter bunny is following our “3 Cs approach to COVID-19 control,” that is avoiding closed spaces, close contact and crowded settings. And maybe the Easter bunny wears a mask too? We’ll probably never know for sure…

Don’t be afraid of the Easter bunny.

Don’t worry about what the Easter bunny leaves behind

No, you don’t need to disinfect Easter eggs.

The biggest risk from the Easter bunny is when the family dog finds all that chocolate first (yes, I am speaking from personal experience). That has nothing to do with COVID-19.

I tweeted recently about the first report of the B.1.1.7 SARS-CoV-2 variant being found in animals, specifically in a dog and cat in Texas, which deserves some more discussion. Also a new pre-print article (i.e. non-peer-reviewed paper) was posted recently that will probably raise more concerns, so I figured I’d better write about that one too.

Texas A&M Research Uncovers First Known COVID-19 UK Variant In Animals

The B.1.1.7 variant of SARS-CoV-2, which first emerged in the UK, is becoming widespread internationally and fueling third waves of COVID-19 in the human population in multiple countries. It’s more transmissible than “regular” SARS-CoV-2 and may cause more severe disease. Fortunately most of the available vaccines still seem to be effective against it, but it’s causing a lot of damage while we’re still trying to get enough people vaccinated.

It’s clear that people commonly pass SARS-CoV-2 to their pets. As this strain (and others) become more common in people, it’s inevitable that animals (particularly the pets we live with) will be exposed too. It’s unlikely (though possible) that the strain will be significantly less infective in animals than the original strain, so we fully expect to see it spillover into pets.  I assume there have been thousands of dogs and cats unknowingly infected with this and other variants of concern (VOCs) so far, but we test very few animals in COVID-19-affcected households. So, the Texas report was an expected confirmation that pets can also be infected with this VOC. We’re testing animals here in Canada too as part of our ongoing surveillance project.

Myocarditis in naturally infected pets with the British variant of COVID-19 (preprint)

This paper, which I will emphasize again has yet to be peer reviewed, will likely cause a bit of concern, but probably unnecessarily.

The authors observed an increase in dogs and cats presented to a referral veterinary clinic in the UK with myocarditis (inflammation of the heart). The concern was that the increase occurred at the same time the B.1.1.7 variant was surging through the human population in the UK.

  • Clinical observations of abnormal patterns are important. Most often, they end up being nothing remarkable – just random changes in normal events, or coincidences. Sometimes, though, they’re an early warning that something is going on. So, they are worth investigating.

Most owners of the affected animals reported having COVID-19 themselves in the 3-6 week period preceding the animals’ illnesses.

  • Interesting. Far from definitive (especially during a pandemic when lots of people are infected), but worthy of investigation.

They collected oro-nasal and rectal swabs from six cats and one dog with myocarditis in late January / early February. They also collected blood from these pets to look for antibodies against SARS-CoV-2. Blood samples were also collected from 4 other pets (2 cats, 2 dogs) that were recovering from myocarditis. None of the animals were reported to have had any respiratory disease.

  • 3 animals (2 cats and 1 dog) were positive on PCR for SARS-CoV-2 on rectal swabs, with a low viral load. All oro-nasal swabs were negative. The PCR test that was used indicated that the B.1.1.7 variant was present, although the test performance isn’t described.
  • Antibodies against SARS-CoV-2 were not detected in these 3 pets. That makes the results a challenge to interpret. Were the PCR results false positives, or were the serology results false negatives? It doesn’t seem like they followed up with later antibody testing of PCR-positive animals. That would help determine if they were antibody negative initially simply because they had not yet produced enough detectable antibodies (as that can take some time).
  • Three other animals (2 cats and 1 dog) had antibodies against the virus. Those animals were either PCR-negative (1) or PCR was not done (2).  If the serological test used was good (no information was provided on test performance or quality control), then I’d assume the PCR-negative, serology-positive animals had been infected at some point in the past.  PCR is only positive for a short period of time when the animal is actively infected and shedding virus, but antibodies can stick around for a long time after the infection is gone.

What does this tell us?

  • That some human-to-pet transmission of SARS-CoV-2 likely occurred (but we already know this happens).
  • The B.1.1.7 variant was involved (ditto).

Overall, 6/11 animals had some degree of evidence of exposure to SARS-CoV-2. That seems like a fairly high proportion, but it’s not far off the numbers we’re seeing with our work and work from other groups in healthy animals from COVID-19-positive households. So this does not provide any evidence of a link between SARS-CoV-2 infection in pets and myocarditis. Nonetheless, I wouldn’t dismiss it, and we should look into it more.

The authors’ statement that “the discovery of B.1.1.7 infected cats and dogs highlights more than ever the risk that companion animals may potentially play a significant role in SARS-CoV-2 outbreak dynamics than previously appreciated” has no substance. This study just showed that animals can be infected. It does not indicate anything about pets’ role in outbreak dynamics or anything else. We don’t want to ignore the potential that cats, in particular, could transmit the virus. However, their conclusion is unsupported and unlikely to be true.

I’m fully on board with their last statement, though: “Therefore, there is an urgent need to greatly accelerate and strengthen the investigations and surveillance of animal infections by highly-transmissible variants such as British B.1.1.7, South-African B1.351 and Brazilian P.1 variants as part of the global response to the ongoing multi-species COVID-19 pandemic.”

We partnered with the Canadian Academy of Veterinary Dermatology to update our MRSP fact sheets for pet owners, including a new look, and a French translation!  Access them using the links below, or on the Worms & Germs Resources – Pets page.

What is methicillin-resistant Staphylococcus pseudintermedius? (English)

Qu’est-ce que le Staphylococcus pseudintermedius résistant à la méthicilline? (Français)

Here’s a pot pourri of reports of staphylococcal infections in humans linked to dogs. Specifically, they’re infections caused by Staphylococcus pseudintermedius, a common dog-adapted species of Staphylococcus. (If you get freaked out reading these, make sure you read the end of the post so you also get the context.)

A 41-year-old man with a history of skin disease and receiving parenteral nutrition (i.e. being fed intravenously) presented with fever, and developed a recurrent infection of the access port of his indwelling intravenous catheter. Staph pseudintermedius was isolated from him and his dog. They recommended he get rid of his dog.

  • It doesn’t sound like they recommended any other infection control measures, and the person did not get rid of the dog initially. He later did, after being hospitalized from the infection.
  • It’s impossible to say, but I suspect there were other (better) ways to reduce the risk of transmission in the household rather than have the patient get rid of his pet, especially if the dog was an important part of his life.

A hemodialysis patient with an indwelling intravenous catheter developed a S. pseudintermedius infection.

  • The authors stated, “Catheter care education should include information about pet exposure and the possibility of zoonotic infections.” I can’t access (aka I’m too cheap to spend the $37 access fee for) the full paper, so I couldn’t see what details were provided.

Infection of an implanted port catheter system by methicillin-resistant S. pseudintermedius (MRSP). MRSP is basically the dog version of methicillin-resistant Staphylococcus aureus (MRSA).

  • The MRSP strain was a type that’s commonly found in dogs internationally.
  • The person was a dog owner, but they didn’t investigate the pet dog and they don’t say anything about infection control measures in the paper.

A 56-year-old woman with rheumatoid arthritis, osteoporosis and common variable immunodeficiency developed a S. pseudintermedius infection of bone and soft tissue after surgery to repair a broken arm.

  • The same bacterial strain was subsequently also isolated from the patient’s pet dog.
  • No high-risk behaviours (e.g. dog licking face or broken skin, dog sleeping in the bed) were reported.
  • The patient had another dog that had a septic tooth and was being treated with an antibiotic, but it died before they were able to get samples. There’s no more discussion of that, but I wonder whether she was the one giving the dog oral medications and had exposure to the dog’s saliva that way. It’s possible the sick dog harboured the same bacterium as its housemate… maybe even more likely, since antibiotic treatment is a risk factor for MRSP in dogs. That’s all highly theoretical, obviously.

A 39-year-old woman receiving peritoneal dialysis developed septic peritonitis (i.e. infection of the abdominal cavity) with (you guessed it) S. pseudintermedius.

  • Peritoneal dialysis (PD) uses an indwelling catheter that goes from the skin into the abdomen.  Infections are the main complication associated with these devices.
  • The patient had a dog that slept in her bed, having close contact with the dialysis catheter.
  • While vague, the authors did address basic infection control issues: “No recurrent infections have been noted since admission with better hygiene and some distance with the pet dog.” and “Furthermore, PD training and ongoing education programs are needed for pet owners to help decrease the risk of PD-associated bacterial peritonitis. “
  • That’s what I want to see – awareness and education, not ignoring the issue or knee-jerk recommendations to get rid of the pet.

The main take-home message from all this: Relax, and wash your hands.

Is S. pseudintermedius a bigger threat now than in it was years ago?

  • No. It’s not likely any more able to infect people than it could in the past. Most dogs harbour the bacterium on their skin and/or in their mouth, nose and intestinal tract. Millions of people are exposed it every day. Yet, infections are very rare. It’s something to be aware of but we shouldn’t over-react.

But there are many more reports of human disease caused by S. pseudintermedius. Are zoonotic infections increasing?

  • Probably not. I suspect it’s a function of better identification of the bacterium by human diagnostic laboratories (they could have misdiagnosed it as a common human staph in the past), and proliferation of journals that will publish single case reports. I’d wager it’s more of an increase in publications than an increase in disease.

Is MRSP from dogs a bigger threat now?

  • Sure, because it’s much more common in dogs than it used to be.
  • However, MRSP is no more likely to spread to people than susceptible S. pseudintermedius, it’s just harder to kill when we have to treat it. It’s an important bug but human infections seems to be rare.
  • We can’t ignore MRSP, but it likely doesn’t crack the top 10 list of things I’m concerned about your average dog and cat transmitting to a person.

So, what should we do?

Staphylococcus pseudintermedius is a bug that’s found in and on most dogs. Most of the time, it doesn’t do anything to us when we encounter it. We have barriers like our skin and immune system to fight off such foreign invaders. When those barriers are compromised, the risk of infection goes up. Preventing infections comes down to very basic precautions like:

  • Hand washing
  • Limiting contact with saliva, nasal secretions and feces.
  • Keeping open wounds or invasive devices (like catheters) away from animals, and in particular, their secretions. (For me, here’s where there’s a difference between sleeping in the bed and sleeping on the bed. I’m ok with an animal sleeping on the bed if there’s no direct contact with the person. If it’s sleeping under the covers with someone, that creates ample, longterm contact for transmission of pathogens.)
  • Good, prompt wound care after any bite or scratch.

One last thing that often gets forgotten: People should make sure their physician knows they have contact with animals, and physicians should ask about animal contact. Most of the time it’s not relevant, but it only takes a few seconds and can provide important information in certain cases.

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