One concept that we’ve recommended for COVID-19 control in veterinary clinics is staff cohorting. That involves keeping staff groups together to limit the risk of transmission should someone be infected. If groups (i.e. shifts, or teams that stick together and don’t interact with others) are formed, any single infected person would have contact with a smaller number of other people, thus reducing the risk of disease overall and protecting the clinic by making it less likely everyone would be sent home to self-isolate for 14 days at the same time.

In the ideal world, we’d strictly cohort permanently.  However, cohorting can be very difficult, depending on staffing, clinic layout and clinic operations. It can cause major scheduling hassles, limit the amount of patient care, and interfere with work in the clinic in general. Like a lot of infection control practices, the cost-benefit has to be considered, and in many clinics, optimal cohorting isn’t sustainable.  But that doesn’t mean the concept should be dropped completely. The goal should be to cohort as much as possible. There is increased risk with decreased cohorting. However, some of that risk can be offset by making sure other things are done really well.

Ultimately, it comes down to two key concepts (as for control of many infectious diseases): keeping the virus out of the clinic, and limiting its ability to spread if it sneaks in.

Keeping SARS-CoV-2 out of the clinic:

Restricting clinic access

Curbside drop off and pick up (including animals and products like food and medications) is very common now.  Anything that keeps clients out of the clinic will reduce risk, as the fewer human-human contacts occur, the lower the risk of exposure to the virus. If only staff come into the clinic, there’s less risk of introduction.


Hopefully everyone’s gotten the point that coming to work when you’re sick isn’t showing you’re a dedicated employee – it’s showing you’re irresponsible. All clinic staff should self-screen every day. Basically, that means paying attention to their own health and not coming to work if they have anything that could be suggestive of COVID-19 (including decreased smell and taste). It’s not a guarantee that no one who’s infected will come to work, because some may have asymptomatic infections, but keeping actively sick people away is still a huge factor.

The demise of the “waiting room”

This will likely apply to many professions, like dentistry and human medicine. Having people congregate in a small waiting area is not likely to be acceptable, possibly ever again. (It never made sense to me in human medicine anyway – lots of people, including sick people, crammed into a waiting area is just a recipe for disease transmission). Rethinking how reception areas are used is good for the long term. Rather than “waiting rooms” they may ultimately be “check-in” and “check-out” areas, where there’s quick, one-way flow on the way into or out of an appointment (for the subset of situations where an owner has to be in the clinic). Check-in by phone, direct admission to an exam room, waiting outside, dropping off the pet and coming back later, and similar strategies can reduce the need for people to hang around together in a small room, and in turn reduce the risk to themselves and others.

The end of walk-ins

This will probably be a common theme in many professions too. Unexpected arrivals disrupt order and measures to carefully schedule how and when people arrive. That doesn’t mean someone can’t spontaneously decide they should swing by the clinic to pick up a bag of pet food, it just means they have to do it differently. That could simply be calling and saying “I’d like to stop by to get some food, I can be there in 5 minutes.” Staff can then have the food waiting on the doorstep, or know you’re coming in at that time so they can make sure the area is clear. Or, they can say “How about in 10 minutes? We’ll have space then.” Yes, it’s still a bit of a disruption, but it’s minor.

Reducing the risk of in-clinic exposure to SARS-CoV-2:


If an infected person is in the clinic but they are wearing a mask, the risk of them transmitting this virus is lower. 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.


Fewer people = less exposure. Working from home needs to be considered whenever possible. That can include tasks like management, completing medical records and calling owners. It can also include telemedicine. Even in situations where an animal has to be seen in person, telemedicine can reduce the duration of contact. For example, for a new puppy appointment, we’d like to have a detailed discussion of a variety of issues, then do an exam and usually vaccinate. We can do the discussion part by telemedicine (with the vet at home), so it just needs to be followed up by a quick appointment for the exam and vaccination. The owner doesn’t need to be there, so by covering the discussion topics first, an owner-less visit or short owner visit can be achieved without compromising animal care.

Clinic flow

Some things can be done to reduce contacts between staff in the clinic as well. We need to be within 6 ft of others at times (e.g. placing a catheter) but tweaks to clinic flow and operations can reduce the likelihood of crossing paths with someone, or having to work in close proximity, or the duration of time that needs to be spent in close proximity. Appropriate measures to do this will vary greatly between clinics, but there are a variety of things that can be done with both procedures and layout (e.g. moving tables, changing office space).

How will these changes be received by staff, and by clients? Some people will complain about anything new. However, there’s enough awareness now that these measures won’t likely look odd to the average person. If anything, I think people are more likely to raise concerns about failure to take steps like this, since they will be the norm in many situations outside of veterinary medicine too. We’re less likely to hear “my vet is doing some really strange things at their clinic”. Rather, if we don’t take reasonable measures, we’re likely to hear “why isn’t my vet doing the things my doctor, dentist, physiotherapist and everyone else is doing?” In addition to creating risk, failure to act may actually drive clients away.

As described by ProMedMail, the Dutch Agriculture Minister has provided another update on the outbreaks of SARS-CoV-2 that have affected at least 5 mink farms in the Netherlands to date (click here for the original Dutch version of the letter).

Another suspected mink-to-human transmission of SARS-CoV-2 has been identified (with potentially infections in  an additional two mink farm staff). These cases appear to be from a different farm than the first suspected mink-to-human infection. The route of transmission is presumed to be mink-to-human based on the gene sequences (and the illness in the mink preceding infection in the people). The sequence data I saw earlier seem consistent with that, but it’s hard to be 100% certain.

There’s also some more information about barn cats. On mink farms, cats would rarely have direct contact with mink (because mink would try to eat any part of a cat that was within reach), but the cats would have access to mink manure, which typically falls from wire cage flooring to the ground below. They have now identified antibodies against SARS-CoV-2 from 7/24 cats on one farm, indicating the cats were previously infection. The virus itself was also found in the samples from one cat, indicating it likely still had an active infection. Whether all 7 cats got infected from the mink (or mink manure), or whether there was subsequent cat-to-cat transmission will be pretty much impossible to figure out at this point.

While a lot still needs to be determined with these outbreaks, information to date highlights some important themes:

  • SARS-CoV-2 is predominantly a human virus but it can spill into other animals.
  • While most transmission is human-to-human, some infected animals can send the virus back to people, and infect other animals. (That shouldn’t come as a surprise, although sadly the One Health response to this virus has been pretty disappointing.)
  • Keeping infected people away from animals, as well as away from other people, is important. It’s better to prevent human-to-animal infection than to have to figure out how to deal with infected animals and worry about spread into wildlife.
  • Reducing the number and closeness of interactions, be they human-to-human, human-to-animal or animal-to-animal (within reason) and using practical precautions when distancing can’t be maintained (e.g. masks, gloves and other protective equipment when handling animals in high risk situations) are the key control measures for this virus.

The fact that there are multiple affected farms in the Netherlands but no reports elsewhere needs to be considered. It’s unlikely Dutch mink farmers are more likely to be infected or have closer contact with their mink. There’s reluctance in some countries to consider or test for infection with SARS-CoV-2 in animals, so whether this is a uniquely Dutch situation or a more common problem that’s not been diagnosed or reported elsewhere remains a question. Hopefully mink farmers everywhere are paying attention to this situation and implementing some control measures. It’s tough to use really good infection control practices in some of these facilities, considering how mink farms are managed and how many animals may need to be handled on a given day (e.g. when thousands of mink are being vaccinated), but measures to reduce human-mink contact whenever possible, use appropriate PPE, identify problems early and keep wildlife (and cats) away from mink barns are important.

COVID-19 derailed our plans for some backyard chicken work (e.g. research and education) this spring, but the emergence of COVID-19 doesn’t mean all other infectious disease issues have disappeared. Some problems will be reduced by the precautions put in place to control COVID-19, but other problems may actually get worse. Backyard chickens continue to be popular and I anecdotally may actually be more common now, at least in some areas, as people spend more time at home (and others worry (unnecessarily) about ongoing access to eggs and chicken at grocery stores).

I’m not anti-backyard chickens. I’m anti-“spending the weekend on the toilet” and anti-“seeing people hospitalized unnecessarily” and, I guess, just anti-Salmonella and anti-Campylobacter in general. I can’t see any redeeming qualities of those bacteria, at least in people.

That’s a rambling lead-in to a CDC investigation notice about Salmonella Hadar infections linked to backyard chickens. As always, these investigations markedly underestimate the scope of the outbreak, since most people who get sick don’t get tested, and chicken-associated infections with other strains that don’t cause enough widespread disease to get tracked don’t get any attention.

Regardless, it’s a reminder that this remains a significant problem.  As of the May 20, 2020 update:

  • 97 people had been diagnosed with the outbreak strain, with disease starting between February 26 and May 1 (see graph below).
  • People from 28 states have become sick (see map below).
  • 34% were hospitalized. None died.
  • 30% were kids younger than 5 years of age.
  • It looks like 4% of Salmonella Hadar isolates were extended spectrum cephalosporinase (ESC) producers – this is characteristic of certain bacteria that leads to resistance to some important and commonly used antibiotics (e.g. 3rd generation cephalosporins).
  • The likely source of the outbreak strain is backyard poultry, both chickens and ducks. These were often purchased at places like agricultural stores, directly from hatcheries or (probably worst case scenario for various reasons) over the internet.

The bias towards young kids is totally expected since that group is more susceptible to infection and probably more likely to be tested if they get sick. It’s also a group for which there is clear messaging: kids less than 5 years of age (and elderly people, pregnant women and people with compromised immune systems) should not have contact with young poultry. That’s a major education and/or compliance gap that’s seen in most animal-associated Salmonella outbreaks.

I won’t get into a full discussion of preventive measures, but the CDC notice includes a good list. They’re all common sense and very practical, but compliance is probably variable and often bad.

Wash your hands and don’t eat poop. Good general advice, but even more relevant if you have backyard birds.  And don’t make chicken diapers your sole infection control plan.

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