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 few quick updates and comments.

Are pugs a high risk breed for SARS-CoV-2?

This question has come up a few times since the report of an infected pug in North Carolina. It has been suggested by some people in news articles that pugs are higher risk for getting infected. Like other brachycephalic (squishy faced) breeds, some pugs are at increased risk of respiratory disease in general. They are also at increased risk of complications if they get a respiratory infection of any kind. But they should otherwise not be at increased risk of getting infected with this particular virus compared to any other similarly exposed dog.

So, pug owners should relax (some have apparently already asked about getting rid of their dogs). If you own a pug, it is probably at increased risk of complications if it gets infected with SARS-CoV-2 (or any other respiratory virus), but it should not be at increased risk of getting infected in the first place, and the odds of any dog getting infected are very low.

Update on two positive cats in New York

Antibodies to SARS-CoV2 were detected in the blood of both cats from New York that tested positive by PCR in late April . This is not unexpected, but it is one more indication that they were truly infected.

Infected cat in France

In a study of cats owned by people with COVID-19 in France, one cat was identified as positive by PCR.  There’s no mention of how many cats were tested (yet). The positive cat had mild respiratory and gastrointestinal disease, and only its rectal swab (not the throat swab) was positive.

This result isn’t surprising either, as it’s likely that a reasonably large number of human-cat infections have occurred. As has been typical so far, the cat had mild disease. I’ve had some anecdotal reports that suggest some cats can get more serious disease but we need to properly investigate those. This report is just one more piece of evidence indicating that human-animal transmission of this virus is occurring. Human and animal health implications of this are probably limited but it’s an area we need to keep studying.

How to practice veterinary medicine in a COVID-19 world is causing a lot of angst. Questions about dental procedures often top the list. Rightly so, since those are perhaps the highest risk type of procedure for SARS-CoV-2 exposure from animals. Dentistry involves close contact with the face and respiratory secretions, and the potential generation of aerosols.

Routine procedures of all kinds have largely been postponed in most areas because of the need to restrict in-clinic care to urgent cases due to potential COVID-19 risks. As we learn more about the likelihood of human-to-pet transmission (our surveillance study is moving along nicely now) and the dynamics of transmission in people, it will get easier to make informed decisions about how to control the risks. Ultimately, patient-side testing might be a useful approach, but it’s hard to say whether that’s going to be needed or even an option, and that doesn’t help us right now.

In times of uncertainly, I’d always rather be over-prepared, within reason. That means erring on the side of protection, rather than being a case report. We have very little data to work with, so we have to base our recommendations on common sense and reasonable guesses. As with pretty much all of our other advice, things may change.  But, since I get asked about this so often, here are my thoughts and considerations around SARS-CoV-2 and veterinary dental procedures. (Remember I’m an internist, not a dentist! Dental colleagues should feel free to chime in and correct my blatant non-dentist errors and provide their thoughts.)

Is the patient at high risk for SARS-CoV-2 exposure?

Querying the pet’s likely exposure risk is a good first step. The potential presence of asymptomatic (human) infections in household contacts means that a lack of known exposure it not 100% protective, but if the pet does come from a household where COVID-19 is present, we know there’s some degree of increased risk. My concerns are also greater with cats vs dogs, since cats are likely at greater risk of infection, and infected cats maybe would have more virus present in respiratory secretions compared to infected dogs.

How long should a patient be considered high risk?

This is yet another area where we have very limited information. However, based on what we do know, it’s reasonable to estimate that the risk of a pet shedding the virus would be very low by 14 days after its last potential exposure. That means 14 days after the last infected person in the household is deemed non-infectious (often 10-14 days after the start of their illness) .

Does the patient have signs suggestive of SARS-CoV-2 infection?

Any acute unexplained onset of respiratory or GI disease in an exposed animal needs to be considered high risk. Lots of things can cause these problems but if there’s plausible exposure, we need to be wary of SARS-CoV-2. That would mean the risk to veterinary personnel would be even higher, and the threshold of urgency for doing any procedure would have to be quite high.

Can the patient be managed by telemedicine and medication?

No, we can’t extract a tooth over the phone. However, some patients might be manageable in the short term (a couple weeks) with analgesics and/or antibiotics (that’s the recommended approach in human dentistry in some regions). We don’t want to throw those drugs around unnecessarily (the demise of antimicrobial stewardship is a concern in human medicine with the focus on COVID-19), but there may be some cases in which we can delay the definitive treatment long enough that the patient is no longer a high risk to staff.

The patient is high risk and the procedure has to be done. How can we reduce the risk?

The first question is probably “should I handle the case?” If a clinic or clinician are not adequately equipped with PPE and are not comfortable handling the case, referral to a colleague or specialist who is is reasonable.

If the case will proceed, here are some considerations for reducing the risk of SARS-CoV-2 exposure:

  • Minimize aerosol generating procedures. This might involve use of older techniques and manual instruments over instruments (e.g. burrs) that will aerosolize respiratory secretions. Think about every step, whether it’s needed and how it can be done the most efficiently.
  • Consider staging the procedure. If the urgent aspect of the patient’s problem can be managed quicker and/or with less use of aerosol-generating techniques, consider taking care of that part to control pain and limit disease, with a plan to finish the job later. Yes, that requires another anesthesia and more cost, but if the best way to fix things involves lots of aerosol generation and that can be delayed, it may reduce the risks.
  • Wear proper PPE. For an animal from a high-risk household, that means a gown, gloves, N95 respirator and eye protection. A surgical mask plus a face shield is probably an acceptable alternative to the respirator and eye protection, unless the animal has signs consistent with SARS-CoV-2 infection. However, the lower the level of PPE available, the more I’d want to limit the procedure and reduce aerosolization.
  • Consider where the procedure will be performed. It’s ideally done in a closed area where aerosols are confined, and where potentially contaminated surfaces are easy to identify and disinfect. Movement into and out of the room should be minimized to limit airflow disruption. The area should be as free of other items as possible, so that there are fewer potentially contaminated surfaces to address when the procedure is done.
  • Limit people in the area to essential personnel only. Make sure no other patients are in the aerosolization zone.

Hopefully we’ll learn more about the risks and the best ways to control them, and hopefully the risks are actually exceptionally low. We need to balance practicality, patient care and occupational health, and we’re trying to do that largely blindfolded at this time. A little common sense and basic infection control knowledge can go a long way, though.

While COVID-19 is almost exclusively a human disease, it’s clear there can be spillover into animals. That’s probably of greatest concern in pets, because of the amount of contact we have with them and the susceptibility of some pet species (especially cats and ferrets). However, while we have less contact with other types of animals, there might still be important implications. We don’t know the range of species that can be affected and the potential animal health impacts in each species. We also don’t want this virus establishing itself in wild animals.  Ultimately, we want to keep this a “human problem” by preventing movement into animal populations, for the sake of animals and ourselves.

A few different issues with different species are highlighted below.


Since this virus almost certainly originated in a bat, there’s concern about it moving back to bats. While the bats species we have in North America are quite different from the suspected source bat species (i.e. Chinese horseshoe bat), we’d rather prevent our native bats from being exposed rather than hope that they’re just not effective hosts. Normal research and surveillance activities that put people into bat environments are being curtailed in many areas to reduce the risk that we’ll expose bats. We have no idea what the risk is, but it’s better to be prudent than to have to do damage control.


The outbreak of COVID-19 in lions and tigers at the Bronx Zoo raised concerns about risks to wild tiger populations. While there’s less human contact with those animals, they often live in fairly (surprisingly) close proximity to people, and there can (normally) be a lot of people visiting parks and reserves. The risk of infection is probably low, but we want to avoid any health hazards in threatened or endangered populations if we can.

A recent ProMed mail post discussed COVID-19 in a tiger at Pench Tiger Reserve in India. It’s unclear whether the tiger actually had COVID-19.  It seems that park staff were concerned because of the reports of COVID-19 at the Bronx Zoo and that their response (i.e. quarantine of staff, banning visitors from the park) was out of abundance of caution rather than an actual diagnosis. Regardless, it’s something that needs to be considered in areas where people can get close to wild cats.


Gorillas are closely related to humans and probably quite susceptible to this virus. The last thing wild gorilla populations need is COVID-19 spreading through them. This is resulting in park closures to protect the animals, with potentially major impacts to local economies (and the parks that protect the animals). Enforcement will be the challenge. Measures are already in place to protect animals from exposure to human respiratory viruses in many parks, and they’re often flouted.

I’ve written a few times about how I’m both utterly impressed and completely horrified about the state of scientific publishing around COVID-19. We’re getting some exceptional research in astounding short periods of time. We’re also seeing poor quality research, lax peer and editorial review and sometimes more of a rush to be first than a desire to be good.

Research should aim to answer a question and there should be a reason to answer that question. Yes, there are some serendipitous discoveries made based on whims, and I’m a big fan of my students doing little side projects to follow up on curious thoughts. However,  successful curiosity-driven projects should lead to proper studies, and not be the end result.

A letter in the journal Microbes and Infection  (Gao et al. 2020) modelled “whether setting free domestic cats protects people from infection” with COVID-19.  The premise seems to be the concern that people might get freaked out about cats and coronavirus, and abandon their cats. Modelling is a critical component of COVID-19 control planning. But, models are only as good as their input data. You have to create the model with numerous assumptions, and the less you know about those assumptions, the less useful the model is. When you have no idea about the parameters but create a model based on one set of guesses, it’s had to say whether it’s useful or counterproductive. The model also has to make biological sense.

Anyway, this modelling study was based on releasing different numbers of cats, and then seeing how many people got COVID-19 from them.  Essentially:

  • The population consisted of people, indoor cats (that never go outside) and “wild” cats that were outside.
  • Each individual could be susceptible, infected or “removed” (i.e. recovered, and assumed to be immune).
  • When a person or cat was placed outside of the house, they moved in random directions. (People could go straight, turn 90 degrees left or 90 degrees right. Cats could turn left, right or turn around.)
  • During the random wanderings, if a cat bumped into a person or another cat, there was a chance for infection of that person/cat. They assumed there was a 2% chance of cat-cat transmission if the cat was infected but healthy or 5% if infected but sick, and 1% chance of cat-person transmission if the cat was healthy and 2% if it was sick.

I’m not a modeller so I can’t comment too much on the overall approach, but it’s pretty superficial. Assumptions have to be made when modelling, and the farther they get from the real situation, the more likely the model will be inaccurate. They had to pick numbers for transmission based on absolutely no evidence.  Are 1%, 2% and 5% reasonable guesses? Maybe, although I don’t think me crossing paths with a cat outside poses any risk whatsoever of SARS-CoV-2 transmission. Since there’s no evidence, I guess you could say those numbers are as good as any, but that doesn’t mean they’re good. Those are the key numbers for everything in the model. If they are off, the data mean absolutely nothing.

It’s an interesting exercise, and something I can see having a student play around with out of curiosity, to see what the get, to see what happens when you change the numbers, to raise some questions and identify the key gaps that need to be addressed for a proper model.  You can see a video of their very basic model below.

They concluded that “fear over domestic cats may be unnecessary.” That’s true, but their study didn’t actually look at that. They actually showed that if cats are allowed outside, more people get sick. I’m not sure that’s actually a valid conclusion, but it doesn’t answer their “does abandoning your cat protect you?” question, because the study couldn’t do that.  Their next paragraph has a more accurate statement: “The better strategy for controlling the spread of the virus is to quarantine pets at home.” If anything, that’s what their study showed (but I don’t think it really tells us anything new or with any substance). I don’t need a model to tell me that if there no outdoor cats there can be no transmission from outdoor cats.

However, it’s possible to get pretty much anything published these days, even little side projects that don’t have much foundation in a logical question or methodology.  Should the publication threshold be “I did this” or “I did this, it makes sense and it told us something useful”? I think my opinion differs from a lot of journals on that.

This is a departure from our normal emphasis, but COVID-19 in developing countries is an important yet often overlooked issue.  Here’s a guess post from a colleague, Dr.  Philip Mshelbwala, who’s from Nigeria but currently studying in Australia:

The challenges of combating novel coronavirus COVID-19 in Developing World: The need for a workable strategy

Philip Mshelbwala DVM Msc

As cases of Covid-19 continue to spike globally and receive widespread attention in developed countries with good health care systems, less is discussed about developing countries with poorer healthcare and public health systems. In Nigeria, the most populous country in Africa with nearly 200 million population, the index cases was on Feb 27, 2020 in Lagos South West. As of mid-April, 627 cases had been reported in 19 states plus the Federal Capital territory (FCT), with 21 deaths. Included amongst the death toll was the government’s Chief of Staff to the government. While these illness and death numbers are substantially lower than many other countries, the scope of the problem is not understood. Testing has been limited, with the Nigerian Centre for Disease Control (NCDC) reporting only 7153 tests as of April 20. In comparison, Australia, with a population ~9 times smaller, has reported >431,000 tests. Therefore, it is unclear whether COVID-19 cases are relatively limited in Nigeria or whether low numbers simply reflect limited testing. When there are ongoing struggles to maximize testing in high GDP countries with high laboratory and healthcare infrastructure, personnel and funding, the challenges to implementing large scale testing in countries with fewer resources, trained personnel and equipment are clear to see.

In addition to the direct health and economic impacts of COVID-19, the pandemic’s impacts confound various issues in developing countries, impacting efforts to improve healthcare, education and other social support systems. In Nigeria, the outbreak has coincided with a time when the Nigerian Academic Staff of Universities Union  (ASUU) has embarked on an effort to highlight and improve underfunding of healthcare and education, including the failure of the government to respect the earlier agreement and issues of non-payment of salaries. While most institutions in developed countries have since moved into virtual learning platforms, there are more profound challenges to maintaining effective social distancing in developing countries such as Nigeria because of the limited access of platforms and infrastructure to facilitate remote learning, working and healthcare. Therefore, the impacts on some of the most susceptible nations are compounded.

The initial response in Nigeria was driven by individual states that took actions to impose movement restrictions, before the federal government placed a total lockdown (except those on essential services) in hot spots states of Lagos, Ogun and the FCT. While the strategy of ‘stay at home’ has worked for developed countries like Australia, that has continued to see a decline in the number of new cases, it has come at a cost. These include substantial government support programs to keep people employed, facilitating supply chains and critical stores (e.g. grocery stores) and engagement of volunteers to help the high risk groups (e.g. elderly) maintain effective distancing. However, these strategies may not be feasible in a setting with a different sociocultural disparity and economic resources. When people cannot eat if they cannot work, and if they cannot secure food while isolating, effective responses are compromised. Increases in crime are of concern. Moreover, compliance has been low due to poor knowledge of the public health implications and poverty, with belief among some that the virus does not exist. Limitations in public health education and confidence in the public health system hamper effective communication and education, further impacting compliance. Some unfortunate instances of reckless attitudes of enforcement officers has further compounded situation, with at least 18 extrajudicial killings during enforcement efforts. While fear may facilitate compliance, it leads to further distrust and hesitancy to engage and access needed government programs. A combination of governmental inertia, inherent funding and infrastructure challenges, limitation in ground level public health abilities and fear or mistrust create a situation where widespread death from both the virus and secondary impacts such as hunger and lack of healthcare access for other problems could cause substantial impacts.

The list below outlines some efforts that are needed in Nigeria. Many are standard responses that are used everywhere. However, there may be greater challenges implementing these common practices, as well as the need for additional or different approaches.

  • Expanding testing capacity through recruitment of university diagnostic laboratories.
  • Recruitment and training of volunteers for contact tracing.
  • Supporting remote teaching by Universities and other educational facilities providing access to online classroom and meeting systems.
  • Maintaining essential government services while maintaining social distancing.
  • Restricting public group activities (e.g. weddings).
  • Identification and provision of food and essential items to those in need, engaging non-Government organizations when relevant.
  • Educate the public on proper use of homemade facemask and hand gloves, while allowing the use of N95 and surgical masks exclusively for frontline health workers, using local languages. This can be facilitated through the use of existing structures put in place by the World Health Organization (WHO) and other partner agencies that have been used for combating polio and other vaccine preventable diseases of children in the region.
  • Educate law enforcement officers on humane treatment of defaulters.
  • Ensure frontline healthcare workers have adequate personal protective equipment.
  • Engage the services of local manufacturers to produce affordable ventilators and invest in equipping underfunded healthcare centres and personnel to ensure that advanced life support such as ventilation can be properly performed.
  • Educate the public about the risks of COVID-19, the reason for control measures and the ways people can protect themselves.
  • Restriction of interstate travel to slow the rate of spread.
  • Invest in research for local solutions to the pandemic, especially on ways to boost  community knowledge.

The toll of COVID-19 on developing countries is not well understood and limitations in healthcare and surveillance mean the impacts in many areas may ultimately never be known. However, when the profound impacts on well funded areas such as New York are considered, the potential impact on underfunded and crowded developing regions, as well as remote and unsupported rural areas in the developing world should be enough to prompt intense local and international action to reduce the health and societal burdens of this pandemic.

We’ll put this in the “interesting but not really surprising” file.

When you have people with COVID-19 and they have contact with animals, there’s some risk of infecting the animals. The risk varies by animal species, but this virus seems to have the ability to infect a few different species beyond our own.

SARS-CoV-2 has been identified in mink on two farms in the Netherlands. There were sick employees at both farms, so it’s assumed the workers infected the mink. Whether it was all worker-to-mink transmission or whether there was any subsequent mink-to-mink transmission is presumably being investigated (difficult as that may be to determine).

The scope of the problem isn’t clear from the reports I’ve read. It’s been stated that between the two farms there are over 20 000 mink, and the ones that were sick had intestinal and respiratory disease. How many were sick and how many were tested isn’t yet clear. Infection on a farm with that many animals is certainly a concern; while mink are generally not housed in cages together, they are usually close enough that aerosol or droplet transmission between animals would still be quite possible.

Roads around the farms are being closed and people are being told to stay at least 400 metres away, while the investigation continues. Issues such as potential virus transmission on dust particles (since other bacteria and viruses can sometimes be found downwind of affected farms) and what to do with the mink manure  are being considered. Manure handling may be a particular concern since shedding in feces is likely, and 20 000 mink can produce a lot of feces.

Cats on the farms are also being investigated. It’s important to know if the cats are also infected as an indicator of whether the virus can spread in animal groups (although the cats could theoretically have been infected by the same workers).  As I’ve said repeatedly, COVID-19 is almost exclusively a human problem, but a small animal component could still be a concern, if animals can re-infect people or act as reservoirs. We’re addressing the animal component in large part to try to keep this as an exclusively human problem.

Infection of mink isn’t surprising because  they’re related to ferrets, and we know that ferrets are susceptible based on experimental work that’s already been reported.  This also shows again how “predicted” susceptibility can be dodgy, as a recent pre-print article on the topic listed mink and ferrets in the “very low risk” category – clearly they are not. We need more study of animals and this virus, as well as continued efforts to keep sick people away from animals, and to keep exposed animals away from other animals and people.