In the midst of outbreaks of COVID-19 on at least 5 mink farms in the Netherlands, a Reuters article reports that Dutch Agricultural Minister Carola Schouten issued a letter to parliament indicating that a farm worker was infected with SARS-CoV-2 from the mink. That’s a bit surprising to me, with the surprising aspect being the apparent ability to identify mink-to-human transmission. How this was determined isn’t clear and more details are needed.  The nuances of what was said also are unclear. A Google translation of a Dutch news report about the case says mink-to-human transmission was “plausible” (aannemelijk), while the English Reuters report is more definitive (“A person who worked on a farm where mink are bred to export their fur contracted the coronavirus from the animals.“).

More clarity is needed.

From a biological standpoint, mink-to-human transmission wouldn’t be surprising. If mink can infect other mink, it makes sense they could also spread the virus to people in close contact (although “close contact” with farmed mink is much less common, and much less close, than human contact with pets, for example). However, identifying animal-to-human transmission when there’s widespread human-to-human transmission is a challenge, especially when people can be infected by other people with asymptomatic infections.

Figuring out exactly how a person got infected can be a challenge in the community.  If someone on a farm gets sick, does that mean they got it from a co-worker, an animal or somewhere off the farm? Evaluation of the genetic sequences of the virus can help figure out who’s linked to who, as subtle changes in the virus occur over time.  Finding an identical virus in two individuals supports a link, but it doesn’t tell us in which direction the virus was transmitted, or rule out the potential that both individuals were infected by the same source. The Dutch report indicates there are similarities in the gene sequences of the viruses from mink and the worker, but that still doesn’t answer the question of “who infected who.” More information about contacts between the infected worker and other workers, contact between the worker and mink, timing of contacts and disease, and genetic sequences of strains found in people off the farm in that region is needed to better understand the situation. I assume much of that will be coming, so it will be interesting to see how this story unfolds.

I keep saying I’m going to stop talking about sporadic new SARS-CoV-2 infections in animals unless there’s something noteworthy. I’ll mention some recent cases in a dog and some cats in the Netherlands because I think there are some unique aspects that fit that bill.

Infected dog

This infected dog was euthanized on account of severe respiratory disease. So far, it has appeared that dogs don’t get sick if they are infected with SARS-CoV-2. Disease of any sort, let alone fatal disease, would therefore be noteworthy in a dog.  One report said “The American bulldog’s blood tested positive for SARS-CoV-2 antibodies, but the dog had tested negative for an active case of Covid-19.” I assume that means it was PCR negative, but that doesn’t mean it wasn’t infected. They added “It was thus unclear if the dog’s worsening condition was as a result of the infection, or due to other health issues.”  Hopefully more testing is being performed  to see if there were other problems that could have accounted for severe disease or whether SARS-CoV-2 might have been the cause.

Infected cats on a mink farm

During our national working group discussions of the outbreaks of SARS-CoV-2 on Dutch mink farms (now 5 affected farms), the question of whether there were other animals like barn cats on the properties was raised. The answer to that is apparently “yes.”

Three of 11 tested cats on the farms had antibodies against the virus, indicating they had been infected. That leads to questions about how they were exposed. Investigating that involves interviewing farm staff to see how much human contact they had, to get some idea whether contact with infected people or indirect contact with infected mink (e.g. droplets/aerosols from being in the affected barns, contact with potentially virus-contaminated manure) was the likely source.  This highlights the importance of preventing exposure of other animals and containing exposed/infected animals. We want to keep this virus confined to humans as much as possible, and not create opportunities for animals to pass it back to people or for animals to spread the virus to other domestic animals or wildlife.

Since we’re entering kitten season, there will be lots of animals in shelters needing homes. I’ve done a couple of virtual talks for shelter groups this week, with a focus on implementing physical distancing and other preventive measures, while maintaining as much of a semblance of normal shelter operations as possible.

I’ve also had quite a few questions from people asking about any risks that might be associated with adopting an animal from a shelter at this time. In all those discussions, I’ve emphasized the need for some basic practices, similar to what you see in grocery stores right now. If a shelter uses good preventative practices, I’d have no hesitation adopting a new pet.

It’s always useful to put a personal spin on discussions like that, and that’s easier since we adopted a new kitten today ourselves.

Was I worried about COVID-19?  No.

  • The shelter confirmed the health status of the fostering family before bringing the cat back to the shelter, and transfer of the critter was contactless.
  • The odds of the kitten being infected or his haircoat being contaminated with SARS-CoV-2 aren’t zero, but they’re exceptionally low. The drive to and from the shelter was likely the greater health risk.

There will always be infectious disease risks when adopting new animals, even without SARS-CoV-2. However, with some common sense practices, the risk of transmission of SARS-CoV-2 is negligible. We’re much more likely to get infected with our typical new-pet-associated pathogens like Campylobacter, but some basic hygiene measures (e.g. hand hygiene) can minimize those risks as well.

Here’s the yet-to-be-renamed kitten. (He actually currently has about 20 names, many of which are hockey players). My personal health risks will probably be greater navigating the family name debate than anything else.



Nothing too remarkable to report, but here are a few recent developments.


Details about the first two SARS-CoV-2-positive dogs in Hong Kong have been published in Nature. We’ve previously heard most of the information before, but here’s a quick summary:

  • Two out of 15 dogs were identified as positive for SARS-CoV-2, after being in contact with COVID-19-infected owners.
  • The first dog was a 17-year-old Pomeranian. SARS-CoV-2 was isolated from nasal and oral swabs shortly after it arrived in quarantine, and it had positive nasal swab results multiple times over 13 days. It also produced antibodies against the virus (seroconverted). The repeated isolation of the virus and seroconversion are convincing evidence that the dog was infected. However, it did not have any apparent signs of illness from SARS-CoV-2. It died shortly after its quarantine ended but that was attributed to its old age and other issues, not the virus (see figure below for timeline info).
  • The 2nd dog was a 2.5-year-old German Shepherd, one of two dogs in the household of another COVID-19-infected person. The virus was detected from sets of oral and nasal swabs collected on arrival and the next day, but further samples were negative shortly thereafter. Rectal swabs were also collected at the second sampling time and were positive. This dog also seroconverted and remained healthy.
  • Unsurprisingly, when they looked at the genetic sequence of viruses from the dogs and their respective owners, viral sequences from the dogs were identical to those from their owners (and sequences from the two households were different). This supports the assumption that the dogs were infected by their owners.


Another couple of infected cats have been identified, one from Germany and one from France.

The German cat’s owner was in a retirement home with an ongoing outbreak, and had died of COVID-19. The cat was infected, while two other cats at the facility were negative. The cat was healthy, as seems to be fairly common with infected cats.

The other cat was the 2nd reported positive cat from France. This cat had respiratory disease that was non-responsive to antibiotics and anti-inflammatories, and it’s quite possible those signs were the result of COVID-19, but we can’t rule out other underlying causes based on the available information.


There are now four mink farms in the Netherlands with confirmed outbreaks of SARS-CoV-2 in the animals. There’s still limited public information about the number of infected mink or information about transmission patterns on these farms. With thousands of animals on each premisis, there is certainly concern about the potential for widespread transmission, as well as ancillary issues such as what to do with all of the potentially contaminated manure. There’s not much mention of illness in the mink, but it’s apparent that at least some have developed respiratory disease, including fatal infections, with pregnant mink seemingly predisposed to illness.

There is still lots of confusion about what use of different types of masks is supposed to do in different situations. As I’ve said before, it comes down to thinking about who the mask is meant to protect – the user, or people around the user. This dictates what type of mask should be used.

Cloth masks

  • These masks protect others from the user’s respiratory droplets – the little liquid particles that we expel when talking, breathing, coughing or doing similar things.  Exposure to such droplets is the biggest risk for transmission of SARS-CoV-2. Cloth masks help contain droplets. While they will help protect the user to some degree, they are mainly to protect others FROM the user.

Surgical masks

  • These are meant to protect others FROM the person wearing the mask (same as cloth masks).

N95 masks/respirators

  • These masks can help protect both the user and those around the user. IF they are properly fitted to create a seal around the mouth and nose (unfortunately many people don’t realize these masks need to be fit-tested to be effective), then they will help protect the user.  However, the user also needs to protect the eyes – it makes little sense to cover some mucous membranes on your face (nose and mouth) and leave two others just above those wide open and unshielded.
  • N95 respirators can also protect others FROM the wearer, since they are good filtering masks, IF they don’t have an exhalation valve.

What is an exhalation valve?

An exhalation valve makes it easier to breathe by allowing air to leave the mask without passing through a filter. That’s fine if the mask is being worn to protect the user, who inhales filtered air and is presumably not exhaling infectious droplets.  However, if the person is infected and there is virus in the expelled air, an N95 with an exhalation valve will not protect others FROM the user. Since most community mask usage is designed to protect others from people expelling infectious droplets, in situations where mask use by everyone is mandated to reduce the risk of exposing others, N95 masks with exhalation valves should not be used.

Cats are susceptible to SARS-CoV-2. That’s been shown experimentally and in a limited number of documented natural infections. However, there’s still a lot we need to know to better understand the feline and human health implications of this virus. While limitations of experimental studies always have to be considered (since they’re based on an artificial situation), they can answer some questions a lot quicker than field studies.

A new correspondence in the New England Journal of Medicine (Halfmann et al. 2020) provides a bit more information about this virus in cats, largely supporting what’s been reported before . I found it pretty surprising to see this report in a prominent human medical journal, since it only involves cats.  I also found it surprising how superficial the information was. I guess they were trying to squeeze everything into a letter to the editor, but they sacrificed providing good information for publication in a high profile journal. They did provide more details are in the supplementary appendix file, but there are still lots of gaps.

The study looked at experimental infection with SARS-CoV-2 in three cats:

  • The day after the three cats were inoculated with the virus, another cat was co-housed with each of them.
    • There is no mention of what, if anything, they did to make sure there was no viable virus on the haircoat of the infected cats after experimental inoculation.
  • Nasal and rectal swabs were collected daily to test for the virus.
  • By day 3, virus was recovered from all inoculated cats.
    • There is no mention if the virus was found on the nasal swabs, rectal swabs or both.
    • It appears that the infected cats were healthy, although how they were monitored isn’t clear beyond saying they didn’t lose weight or have abnormal body temperatures.  However, their graph shows 2 of 3 infected cats had a 1C temperature jump by 24 hours post-infection, and one of the co-housed cats seemed to spike a fever on day 7.
  • Virus was ultimately detected in all three cats co-housed with the inoculated cats.
  • Virus was detectable for several days in all cats (see graph below).
  • All cats developed antibodies to the virus, further confirming they were truly infected.

My take home messages from this study aren’t really anything we didn’t know before, but it’s still useful confirmation:

  • Cats can be infected with SARS-CoV-2.
  • Infected cats don’t necessarily get sick.
  • Cats can spread the virus to other cats.

Since cats can spread the virus to other cats, the logical question is whether they can spread it to people. It’s logical to assume that they could, so it makes sense to take some basic precautions around exposed cats (like we’ve been saying for months). This is nothing new or scary, just a reminder to keep using some common sense preventive measures.

As the authors state, earlier reports, “coupled with our data showing the ease of transmission between domestic cats, [show] there is a public health need to recognize and further investigate the potential chain of human–cat–human transmission.”

Well said.

We’ve spent a lot of timing working on various recommendations for managing COVID-19 risks in veterinary practice. They’re mainly focused on the most biohazardous species with which veterinary personnel work on a daily basis: humans. While we’re still sorting through animal-related issues, the main emphasis is reducing exposure risk from people, and a recent assessment from the UK’s Office of National Statistics shows why. They have an interesting interactive map that characterizes the risk for a range of occupations, based on the frequency and closeness of contact they have with other people in general, and the potential exposure to infected people specifically.


  • Not surprisingly, healthcare practitioners top the list, particularly dental nurses.
  • Where veterinarians and veterinary technicians rank might surprise some (take a guess then check out the link to the interactive map here).  This shows why we’re working so hard on this, and why some short- and long-term changes in behaviours and veterinary practice are needed to help protect everyone’s health.
  • It’s designed as an assessment of generic disease exposure, not just COVID-19, so the vets and vet techs get higher on the ranking than they would be on a strictly COVID-19 exposure risk assessment, but it highlights the amount of close contact that vets have with a large number of people on a daily basis. More contacts means more risk. Reducing those contacts reduces the risk

Pretty soon, I’ll stop writing about single reports of cats identified as infected with SARS-CoV-2. These cases aren’t surprising,  and sporadic case reports don’t provide much new information. However, I’ll give a quick rundown of the latest case of an infected cat from Spain. It’s only reported in news articles, as far as I can find, so we have to be a bit wary of the info.

As expected, the cat lived in a household with COVID-19-infected people. The cat developed respiratory difficulties, and was ultimately euthanized. Low levels of SARS-CoV-2 were found in its nasal passages and an abdominal lymph node. But the cat also had hypertrophic cardiomyopathy, a potentially serious heart disease that can cause death.

This case raises concern about a severe SARS-CoV-2 infection in the cat, which would be different from the milder cases that have been previously reported. However, the cat’s underlying health issues could have accounted for its death, so it’s more likely that the cat had an incidental infection rather than a fatal SARS-CoV-2 infection.

Regardless, my assumption has been that we’re bound to see the odd case of serious disease in cats. I get some calls about suspicious cases, but we haven’t been able to test too many of them. Most infected cats probably don’t get sick at all or develop mild signs of illness (like people), but it’s reasonable to expect that a subset of infected cats (especially those with underlying health problems) could get more serious disease, but that’s likely rare. However, most cats exposed to infected people likely don’t even get infected.

As per all my other discussions, the key here is that if you social distance pets (as we do people), then the risk that a pet would bring this virus into the household is very low.

We’re nowhere near the end of this pandemic, and one concern we have is opening things up too quickly and losing the benefits of all the sacrifices that have been made to “flatten the curve.” As restrictions get lifted, we’re not going straight from “now” to “normal.”  We’ll have to continue with good physical distancing practices for the foreseeable future.

With that in mind, a new document has been released, in collaboration with the OVMA, outlining preparation for veterinary medicine when the “urgent care only” directive in Ontario gets lifted. It’s meant to help us be prepared for the next phase, so that we can provide more veterinary services while still minimizing the risk of COVID-19 transmission.

That’s a difficult balance to find.

The document is written for the Ontario context, but the overall concepts would likely apply pretty much anywhere. We’re going to have to change how we practice for a while, and some changes may be permanent. The better we can be prepared, the more responsible and effective we can be.

As always, guidance may change based on how the pandemic evolves, government guidance, experiences and new ideas, but this is a good place to start.

You can find the Guide to reopening veterinary medicine in Ontario as well as many of the other resources we’ve posted since March on the Worms & Germs COVID-19 Veterinary Resources page.

A recent report from the Canadian Wildlife Health Cooperative (CWHC) describes an outbreak of tularemia in muskrats in Long Point, Ontario. Tularemia is a potentially nasty disease caused by the bacterium Francisella tularensis. While not many people have contact with muskrats or live in Long Point, it’s still noteworthy.

 The investigation was  initiated following a report of at least 35 sick or dead muskrats in the area. Necropsies were done on some of the rodents, and they were found to have enlarged lymph nodes and lesions in their spleens and livers. Testing at the National Microbiology Laboratory identified Francisella tularensis.  This was done at the national lab because F. tularensis is a containment level 3 pathogen requiring enhanced biosafety practices – so it’s not a bacterium which regular labs handle.

This isn’t a new finding, since we know this bacterium is present in Ontario, but it’s rare. Francisella tularensis is sporadically found in various animals and rarely in people (there’s been one reported human case in Ontario so far in 2020). It’s a reportable disease in animals and people because of the potential severity of infection, and because it’s a potential bioterrorism agent.

Back to the muskrats… tularemia is a rare finding in wildlife. That doesn’t mean it doesn’t cause disease, since sporadic disease in wildlife rarely gets investigated. It’s most commonly associated with rabbits, and human and domestic animal infections can be associated with rabbit or rodent contact. The fact that this occurred as an outbreak with a significant number of animals affected over a short period of time is interesting, and it’s also concerning from human and animal health standpoints. The bacterium can be spread in a variety of ways, including direct contact, inhalation (e.g. running over an infected animal with a lawnmower and aerosolizing the bug and then breathing it in… gross but true) and via some insects (e.g. ticks, deer flies).

Tularemia avoidance measures are pretty basic:

  • Avoid contact with wildlife, live or dead.
  • People handling dead wildlife, especially those handling them closely such as trappers, should use good routine hygiene and infection control practices.
  • Avoid ticks. For pets, that involves use of a good tick preventive. For the rest of us, well… we don’t have a chewable tick preventive but we can do other things to reduce the risk of tick exposure, including (and most importantly) doing “tick checks” if you’ve been outside in an area where ticks are likely to be lurking.
  • Keep your pets under control, especially if they are prone to chasing wildlife or snacking on dead animals (also gross but true).

The CWHC warning is pretty similar to my comments: “During an outbreak situation, it is presumed that bacterial levels would be higher in the surrounding environment, so caution is warranted for anyone who is traversing through the area or wading into the water in the Crown Marsh area of Long Point. There is also a danger to off-leash dogs as they can become infected and develop similar symptoms to humans, especially if they consume infected meat. It is recommended that dogs are kept on leash and monitored closely while in this area. It is recommended that people do not handle wildlife found dead unless they are wearing protective gloves (or a similar protective barrier) to prevent direct contact of the animal with the skin. Anyone who handles dead wildlife (even while wearing the appropriate protective gear) should wash their hands thoroughly to minimize the chances of exposure.

A related topic that applies to animals and people is talking to healthcare providers about travel. The risk for various diseases differs geographically. A disease might not be on a physician’s or veterinarian’s list of considerations if they don’t know about travel. So, physicians and veterinarians need to query travel history, and everyone needs to remember that travel means going somewhere else, regardless where it is (even if they haven’t left the province).

Here’s a scenario that highlights that:

Me: Have you traveled with your dog lately?

Owner: No.

Me: Do you have a cottage?

Owner: Yes, it’s a beautiful place a couple of hours from here. We go there every weekend in the summer.

Me: So, you travel with your dog every weekend in the summer?

Owner: Well, that’s not travel, it’s going to the cottage.

Me: Ok, now let’s talk about the different things I need to consider now that I know your dog travels.

That’s not an unusual situation. Understanding where people and animals have been is important when thinking about infectious disease risks. Veterinarians and owners need to clearly communicate to identify potential problems.