Veterinary Medicine in the COVID-19 Era: Where Are We Now and Where Are We Going?
J. Scott Weese, DVM, DVSc, DACVIM (LAIM)
The transcript below is derived from the VIN/VSPN Rounds presented on August 20, 2020. Click to view the slides.
VIN & VSPN members may access the video recording and other resources from the session page [login required].
Carla Burris: Tonight's speaker is J. Scott Weese, DVM, DVSc, DACVIM (LAIM), from Ontario Veterinary College's Centre for Public Health and Zoonoses. You may know him as a VIN Consultant in the Infectious Disease folder and an author of the Worms & Germs blog.
Welcome, Dr. Weese! The floor is yours.
Slide 1 (View the slides.)
Scott Weese: Great. Thanks for coming out tonight. It's nice to be back talking about this. I was telling Carla before that I was thinking that maybe there wouldn't be a ton of big things to talk about and we could focus on a lot of questions. Then I got going and realized there was a whole lot that we could probably keep talking about.
I've got a lot of slides here. We'll take as many questions as you want. I'm happy to stick around after if there are any more or followup after.
What I want to do is really focus on the bigger aspects of COVID, and that's how we run practices and how we practice veterinary medicine. It's going to be fairly light on the animal side because there is not a lot new to say about the animal side. This is a predominantly human disease, so I'm going to hit on the animal aspect. It's going to be fairly short. More what I'm going to talk about is our risk in clinics, how we mitigate that, how we assess that, and how we function, because we're not getting back to normal for a while. If we're all vaccinated by this time next year, I'll be pretty happy. By the time we get a vaccine and get it to everyone that needs two doses and get that done, it's going to take a long time before we get reasonable protection. We're in this for the long haul, as I think everyone realizes now.
I'm not going to talk much about where we stand with human cases. I'm going to point out a couple of places where you can find some information. Understanding what's going on in people is obviously important because that tells us where we're going. It tells you the risk in your area, but knowing your local epidemiology is important because that helps you figure out what you can do in your clinic and what risks you have and how much risk you can take, how we can balance protection and the practical aspects.
There are various places you can get good information. The one I use most is from StatNews. It's a very reputable site. They have very good data. The link is on the bottom there. You can look at it in various levels. I'm not going to talk really about the numbers. These are U.S. national data, and you can see it wasn't really the second curve because the first curve didn't really drop, but that big peak that's happened over the last month or so. Hopefully some trending in the right direction, but that's variable.
That's national and it's interesting, and it doesn't tell you that much about your area.
Then you can drill it down. You can see this is California. If you look on the left side of the screen, you can see what happens in cases in California. You look at two-week rolling cases, average stats yesterday, and average stats two weeks ago.
You can drill that down even more and this is by county – county level data – and you get a little more applicable, obviously to your own situation and in your own state or your own province or your own country. If you're looking for something that tells you about your area, you may have good reports through your public health units. You may have other places that give you information. If not, this is a good summary.
Knowing your local epidemiology, like I said, I think is quite important because we have to figure out how far we need to go on restriction. I'm going to talk about letting people into the clinics. I'm going to talk about what we need to do to reduce that risk. If we understand what the risk of someone bringing in this virus is, it lets us figure out how far we want to go with our restrictions.
You've heard lots of different things about the epidemiology. You've probably heard about R0, the basic reproduction rate. R0 for this virus is around 2 or 2.5, which means in a normal state, uncontrolled, your average person is going to infect 2 or 2.5 other people, and that's how it gets exponential. You go from 1 to 2.5 and to whatever that is next. That's an important number, and that's an inherent property of the virus.
Rt is what the real R0 is, the functional R0. R0 is 2 or 2.5, but if we're doing things well, the actual transmission rate should be lower. If we're doing things poorly, that transmission rate might be higher because we're creating more opportunities. Understanding the reproduction rate and the transmission rate in your area is important, understanding the new case rate, and understanding test positivity (I'll come back to that a little bit more), and testing numbers. If you can find local data and you're trying to pay attention to what's going on in your area, these are four metrics that are really important. I'm going to show some examples just from my area here.
This is information I get every day in Ontario. This is by our health units. I work in the Wellington-Dufferin-Guelph Health Unit.
Just a couple of things that we see here – our R0 is around 1, so that's kind of steady state. Your average person infects one other person. That's not bad. It's not going away, but it's not getting worse.
You can look at our weekly cases per 100,000 is 3, so it's pretty low. Our province is doing quite well right now.
We can look at our new hospitalization rate per million. We've got 0 over the last 14 days.
You can look at some other interesting things, and here's where you start putting the risk of clinics into perspective. With some of these numbers, this number down here basically says if you encounter 1300 people, you've got about a 50% chance that one of them has COVID. It starts putting that into perspective. That's obviously a lot of people before you see that first infected person.
Knowing some of these can put it into perspective. If 1 in 10 people coming to your clinic might be infected, we'd need a lot more aggressive approach than if it's 1 in 10,000. These are data I look at every day.
If we look at the province of Ontario, like I said, we're doing quite well right now. Whether we're going to get a second wave – we're worried about that. The province of Ontario is about 14 million people. We have 10 people in ICU on ventilators. We have 16 in the province in ICU, so we're actually doing exceptionally well based on that. I think this shows what we can do with reasonable precautions. We're not locked down. We've got masks, we've got distancing, we have restriction on some activities that are high risk, but it shows I think that you could be doing normal-ish activities and keep things hopefully at bay. What it will be like in a month is hard to say.
If we look again provincially, our positivity rates are about 0.3%. A couple of days ago at least, it was based on 30,000 tests. This is an important number too. This is the percentage of people that get tested that are positive. You've seen some reports (especially in some U.S. states and they've had big problems) where that number is 10, 20, or even 30%. When that rate is really high, it tells us a few things. It tells us it's very poorly controlled because you're seeing a lot of cases, but it also tells us we have a very poor understanding of what's going on.
Here, if we say 0.3% of our tests in Ontario were positive, we can assume that we're testing a high-risk group. We're testing people that are sick and people that are exposed preferentially. Are all the people that we're not testing lower risk than that, so we don't have a lot of people that are probably silently infected? If our positivity rate was 30%, we've probably got a lot of people that are positive.
It's been estimated based on these numbers that if your test positivity rates are around this, you're probably getting 80 to 90% of the cases. You're actually capturing the vast majority. If your test positivity rate is 5 to 10%, you're probably getting 20 or 30% of them, so you've got a large pool of unknown positives to worry about.
If you're on Twitter, Ryan Imgrund you can see is the top right here. He's the one that puts out some of these data. He comes up with some international data just to put some numbers in perspective of where you are and comparing to different countries. These are weekly cases per 100,000.
Reporting bias is a big issue. India has got a fairly high rate that's massively under-reported, we assume. In the U.S., you can see the rate is pretty high. That's from a couple of days ago, just to put different countries into perspective if you're curious. Knowing your local epidemiology is really the key for assessing practices.
If you're thinking about what's going on in your area, a big concern is no data if you're flying blind. If you're getting data, one thing that would indicate that you've got more risk in your area and we want to be more careful would be a high Rt.
One thing to be aware of is if you don't have a lot of cases, the Rt is very volatile. If I've got one person in this city that's infected and all of a sudden they infect four family members, my Rt has become 4, and then it's going to crash a couple of days later when they get washed out of the data. If you don't have a lot of cases, your Rt can jump around a lot, but look at your Rt. If your Rt is 2, 3, 4 or 5, whatever you've got amplifying, you've got exponential growth in your area and you don't have it well controlled.
High new case rates. High new hospitalization rate. We look at the hospitalization rate at the community level because we're worried about hospital capacity, but if you don't have very good surveillance in your area, hospitalization rate is good. If you're sick and in hospital with signs suggestive of COVID, you're getting a COVID test almost certainly. Even if you've got poor community testing, your hospital data are probably more comparable to other areas than your community data.
Like I said, high test positivity, low test numbers, and something I really get worried about is we've got decreasing test numbers in the face of high test positivity, increasing case rates, increasing Rt because then things are starting to spiral out of control, and you're not getting the data to know where you're going.
If you're able to get local data, these are the things to look at. There aren't that many numbers, but it tells you some semblance of what the risk is in your community.
Just to show one more thing (I'm going to get off the data very soon). These are some more examples from Ontario. Using those data, you can come up with things like this. Basically, this shows that if you meet 100 people, I've got a 3% chance one of those was infected over a certain time period. This gets relevant for the clinic. Think about how many people come into your clinic or how many people you encounter occupationally on a given day. If you're in a high-incidence area, the chances that one of them is infected gets higher. It just puts things into perspective. It's useful for education to remind why we're doing some of these things. Even in a low-risk area, 2% is still a reasonable percent. Again, we multiply that by the months that we're going to have to do this, but you undoubtedly are getting people with COVID that are going to come into your clinic if you're opening doors, and that's why we want to make sure we've got some measures in place.
Enough with the numbers.
Transmission is somewhat of a controversial area. It's probably less controversial scientifically than it's poorly communicated. That leads to confusion.
This is a droplet-borne disease, so large droplets over close distances are the driver of this as well as direct contact – close contact, close face to face interactions. Droplets don't travel very far. These cause the majority of infections.
Fomites and surfaces – it's a bit of a pet peeve of mine. A lot of people are focused on all we're doing – all this cleaning and disinfection. We're focusing on cleaning and disinfection. Sure that's great, but fomites and surfaces are probably are minor players here. We want to take care of them, but we can't do cleaning and disinfection at the expense of droplet transmission control. Fomites and surfaces probably play a limited role, some role.
Then there are the aerosols. We've got droplets and we have aerosols and we have airborne. It's a bit of continuum. Droplets are big things. They don't travel very far. Aerosols are smaller things. They travel a bit farther, and then you get into these really tiny particles, the airborne particles, and they travel longer and they stay in the air longer.
If we look at a truly airborne disease, it would be like the measles. Measles have an Rt of 20 or 25. If you're in the grocery store and someone in the grocery store two hours ago had measles, you can get exposed to measles. That's a highly transmissible airborne virus. That's not what this is. This is one where you're standing in line close to someone for quite a few minutes and you're breathing or they're coughing, and you're expelling droplets over a close range – that's where most of this transmission occurs.
This next slide just shows that. This is a log scale on the bottom. This is droplet size. Bigger droplets have more virus. If you're breathing, you're expelling some virus, and you're expelling fairly small particles so there is not a lot of virus in them, and they're not traveling all that far because you're not forcefully expelling them.
At the other end of it, we've got sneezing. With sneezing, you're propelling these suckers out there. You've got big droplets. They have a lot of virus in them. Some of these are going to travel farther because of the force. It's not just one size. When you sneeze, you're making some big droplets that are flying and some smaller guys. The big ones are the most infectious. They don't go very far. The smaller guys go a little bit farther.
We talk about this 6-foot distance a lot. In some places they talk about 3 feet. There is nothing magical about it. Risk doesn't just disappear when you get to 6 feet. It's a bit of a continuum.
This is a non-scientific graph on the right, but it's just my hand scratch of kind of what it is. Very close is where the risk is high. As you get farther away, that risk drops. When you get to 6 feet, that risk gets pretty low – especially if it's a short-term thing. If I'm standing by someone for a minute or I'm walking by someone at 6 feet, the risk is exceptionally low. If I'm there for a longer period of time, the risk might go up. If it's at 12 feet, well maybe there is some potential risk depending on the person and depending on what they're doing – coughing, sneezing – and their viral load, airflow, and everything else. We can't say that if you're greater than 6 feet away you're good. You're lower risk. It's a continuum.
This is where you get into the aerosol side. We can't say aerosols don't play a role. They probably just don't play much of a role. That's a tough message to get across. We're going to focus on the things that are greatest risk (which are droplets), and we're going to realize that there is that continuum where smaller particles might do some things. I'm going to come back to this when we talk about ventilation in clinics, so maybe I'll just shelve that discussion right now.
This is a paper if you're interested in it. This is talking about airborne transmission. This is a good critique of it. Essential the take-home is transmission beyond 2 meters is possible. It probably happens sometimes, but with this assessment, long-range transmission beyond 2 meters in 10,000 patients they looked at hospitalized seemed to be rare at best. "It's possible" and "something that we are going to deal with or do something with" are a different story.
This is a really a big message for me I think. This is an infectious disease physician. We're talking about COVID acquisition in healthcare facilities, human hospitals. What the general line now is people that got infected in hospitals probably didn't get it from patients. Much of the risk was transmission in lunchrooms and break rooms and meeting rooms. If you look at healthcare workers, the COVID acquisition rates in people that worked on COVID wards were no higher than people that worked on the non-COVID wards. The PPE and the procedures worked around COVID patients, so they weren't getting infected from their patients. Healthcare workers were getting infected from each other, bringing it in from the community, so they were passing it around each other as opposed to getting it from patients.
This is important I think for us, because this type of thing we can run into in a clinic. If we're doing really good barriers with the public and clients or hanging out in close contact within the clinic, maybe that's our biggest risk depending how we're all acting and what our risks are. It's that close contact which is the concern.
We talked about the three Cs – closed spaces, crowded places, and close-contact setting. Do you know what that describes? An exam room in a vet clinic. It's a small room. There's often crappy ventilation. There might be a couple of people in there. You've got conversation. You've got things that generate droplets.
The fourth C that I would add in there is continuous release, the time component, because that increases the risk.
If someone is in a small exam room, you pop into the small exam room and say, "Hi, how are you doing? I'm going to grab your pet. See you later." The risk of that is very little. If you go in there and you spend 15 minutes hanging out with them talking with them, that risk is getting higher and higher because we're in an enclosed space, we've got more chance for droplets to be exchanged. If there is an aerosol component, we've got more time for that to build up in a poorly ventilated area.
When we're thinking about what we want to do in clinics, we need to think about the three Cs (or potentially the four Cs) – avoiding closed spaces, crowded places, close contact settings, and especially avoiding long-term contact with people in those types of situations. That's what we need to be thinking about when we're thinking about clinic operations.
I said I was going to get off the numbers. I lied. I want to talk about one more transmission thing, because this is an interesting but an important aspect too.
We talk about R0. The R0 for this virus is around 2 to 2.5. The R0 for flu is around 2 to 2.5. If you look at this, it's a pretty typical Bell curve largely. Most people with flu infect 2-ish people. The odd person infects a lot more.
This virus, SARS-CoV-2, is different. It's what we call an over-dispersed virus.
In fact, the majority of people that are infected infect no one. The median number of secondary infections is zero. Some people infect a couple. Some infect a lot. It's a weird virus in that most of the time it behaves like MERS (Middle East Respiratory Syndrome), which is very poorly transmissible in the community. It's got an R0 of 0.3 so we don't see community transmission of that virus, but sometimes it acts like measles or it spreads really effectively, and we don't really know why.
Here's a good example of that. This is one person. This is a man in Ohio County. He had COVID and he was at a church service. He infected 59 people I think it was. Thirty-five of those didn't pass it on any more. The blue ones are that first-generation transmission. He infected all these people. Some of them infected one. That one infected three ultimately. The majority of them infected no one. This guy infected 59. He's a super shedder. The majority of people didn't result in any transmission.
Why was he a super shedder? Well, there are various reasons that it might be.
It might be behavioral factors. He was in a church, so there are some issues there. There's singing. There's talking. There's maybe poor ventilation in a small space and a lot of people, so there's a biological factor there. Maybe he's just got a lot of virus. Some people produce a lot more virus. Maybe he was actively sneezing and coughing at the same time. The behavioral and their biological factors are probably associated with super shedding. Even though most people don't infect anyone, some infect a lot, and the problem for us is you don't know who the super shedder is until they super shed. You don't know that anyone coming into your clinic is a super shedder. The only way to find out is if everyone gets sick.
We have to realize that most people aren't going to infect, but anyone that you see might be this person that's going to infect 10, 20, 30, 40, or 50 people. We have to be wary of that.
We'll see what happens. This is from the University of North Carolina. Universities in the U.S. opened a couple of weeks before Canada, so we're getting to see what's happening down in the U.S., and it's not looking good. Places that were trying to go in person, it's not really working out because you're seeing the three Cs. You're getting students that are mixing together, very close contact, very few barriers, and sometimes confined spaces. A house party is a classic disaster, and we're seeing transmission. This has become a young person driven disease at this point.
That's the human side. I'll be happy to answer any questions as we get going. Maybe we'll pause and answer some questions at some point.
I'm going to touch on the animal side now. You've probably been following this. There's not a whole lot new to say.
I'll hit on some things here anyway. This is predominantly a human disease. It's a zoonotic pathogen. It started off in animals, but it's spreading really effectively human to human. Now it is going into other animal species. The relevance of that we're still trying to sort out, but this is being driven by humans. The stuff we're look at in animals is interesting; we're hoping we don't have animal reservoirs.
The best-case scenario for us with this virus is it's a purely human virus – then we only need to worry about people. The second-best case scenario is it's essentially a human virus where you get dead-end host transmission to animals, so we don't have to worry about animals. The worst-case scenario is we create animal reservoirs – domestic animals or wildlife. That's why we're paying attention to animals, because we want to hopefully see that this is a human disease.
Dogs are quite resistant to clinical disease. Human-to-dog transmission as you know has happened. There have been 13-ish cases reported in the U.S. with very limited surveillance. It's been reproduced experimentally, but they're not very susceptible. Whether they get sick is a bit debatable. There was a report of a dog that died. The question is – there have been some dogs that have been sick and they've had this virus there, but they've often had other issues, so have they had COVID or have they been sick and then been infected with this virus? The more human-to-dog transmission that's going on under the radar, the more likely we're going to see just this secondary coincidental thing. We've seen some situations where we think that maybe it's happened, but it's difficult to differentiate that.
Dogs don't seem very susceptible to disease, so hopefully they're rare, dead-end hosts. If you look at experimental data, they don't shed a lot of virus. Virus shedding was identified in a dog in Hong Kong – a live virus in the dog's nose, so there's a plausible risk there – but we think that dogs would be lower on the risk of infecting people. If they get infected, they're probably shedding the virus for a short period of time, and they're probably not shedding a lot of virus... but if there's virus there, there' some risk. The big thing though really with dogs is if my dog is infected, he got it from me or from someone in my family. If my dog doesn't encounter anyone else, he's a dead end. It comes back to that social distancing of households. If people have COVID in the household, we want to keep their animals away from other people, including going to vet clinics.
USDA has numbers if you're looking to see what's going on. You can see on the right there we've got a mix of cats and we've got a mix of dogs. We've got some mink that I'll talk about in a couple of minutes, and then the wild felids out there.
This is based on relatively limited screenings. It's probably reasonably transmissible. I'll hit on the serological reason for that in a bit.
Cats are more susceptible. There haven't been as many cats as dogs tested, and that just may be a function of dogs get more care, and dogs are easier and more likely to get tested.
Experimentally, cats are susceptible. They can get sick. They don't have to get sick. Probably the majority of cats that get infected don't get disease would be my guess. Some get disease. Whether some get really serious disease is questionable.
There was one study out of Colorado where they tried to re-infect the cats after... about a month after, I think it was, and they were immune to reinfection – which is really encouraging, at least in the short-term protective immunity. How often this happens, the overall risk is a bit unclear.
If you're interested, there are a few papers out there that describe some of the epidemiology of exposure. I'm not going to go into that for time reasons. I want to talk about this one on the right a little bit, because this comes into risk.
This is the experimental study of cats. Here is one cat. It was infected. I'm not sure if you can see my pointer, so it's A on that graph on the right in blue. Beside it there's one in orange. That's a contact cat. They infected/inoculated cats, and then they put them with other cats. You can see the infected cat shed the virus up to day 6. The cat that it lived with took a couple of days before it got infected, and it shed virus for five days. This is kind of a typical number we see with experimental studies. There has been a little bit longer maybe in some of the field studies, including the wild felids. If an animal is infected, they shed for a fairly short period of time, probably a few days on average. When we're testing them based on PCR, there's a very short window of time where they're going to be positive, so we're going to underestimate the amount of transmission. From a risk standpoint, this is really good because if an animal has been infected, there's probably a very short period of time they can pass it on to us. A cat can infect another cat, so it makes it logical that a cat could infect a person. They've got a live virus of the mucous membranes that they can infect another animal with, so they could probably infect another person, but we just don't have any real evidence on cat-to-human transmission.
Seroprevalence is where we're going to get more into these. If you look at data based on PCR, what has to happen is we have to go to a household, and we've got a study where we do this. We've got a positive household where some people have COVID. We go into the household and we sample the animals. Logistically it's a pain. We've got to get in there. We have to go into the household because we don't want anyone leaving that house, including the animals. As from that previous slide, we've got a very narrow window to sample them. We can probably get a lot of negatives because the animal hasn't yet started shedding or it's already done shedding by the time you get in there, so we're going to underestimate the number of cases.
If you look at seroprevalence data, there's one from Wuhan that came out a while ago that was 14.7% of cats, and these were largely feral cats. Were some of them released from households with COVID? We don't know, but that's a pretty impressive number that had antibodies.
This study was a preprint in Italy, where it's 3 to 4% of dogs and cats, and this is based on just convenient sample. This isn't households with COVID. This is just samples of cats going to clinics, but an appreciable number there.
We're working through a serological study right now so I don't really have any numbers to release, but I can tell you if we look at households where someone had COVID, seroprevalence in pets is pretty high, so I would suspect that actually human-to-pet transmission is probably fairly common – mainly sub-clinical infection or mild or unnoticed infection. Whether they're infectious is hard to say, and they probably don't pose a risk because hopefully the people are staying home because they're infected and they're keeping their animals at home with them. It still reinforces if we have an animal coming from a positive household, there is some risk that that animal is infectious at any point when it comes in to us, because they can be infected and they can be shedding the virus for a little bit of time at least. This is why we want to ask about owner household's COVID status and take some precautions.
Then there's the mink story. The mink story has been focused on the Netherlands, where we weren't too surprised because ferrets were susceptible to the original SARS. Ferrets are quite susceptible to this virus experimentally, and mink are related to ferrets. The Netherlands has had into the 30s now the number of farms that have been infected, so humans (these are mink farm workers) have infected the mink, and then the mink do a really good job of passing it mink to mink. A lot of them are healthy. Some will get sick. Some will die, especially the pregnant mink. There has been mink-to-human transmission. That's raised some concern. From the theoretical standpoint, a mink is not that big. There is probably not a ton of virus in the mucous membranes, but there's enough to infect workers on the farm. It just reinforces that potential for mink or animal-to-person exposure.
There has also been transmission to cats on these farms, feral cats. They're probably getting exposed through manure. They're not in contact with the mink, but again showing the concern about having an animal reservoir, because mink certainly seem like they can be a reservoir.
That was in the Netherlands, then it was in Denmark and in Spain, and just this week reports of mink infected in the U.S. It wasn't surprising. We'd been expecting it to happen. We've been planning on what to do in Canada for a while because we have a small number of mink farms, so we have some here too.
Again, it's when you get enough people that are infected that get exposed to different animals, we see transmission to those animals.
There's that report from mink in Utah from a few days ago.
Mink obviously are related to ferrets. We actually don't have good data on pet ferrets. We've got experimental data. Is this just because there aren't that many ferrets, nor that many ferrets that go into the vet? Most of them probably don't get very sick. They don't get taken to the vet. Is it because some clinics aren't looking at ferrets now – especially ferrets with respiratory disease, because that's certainly happening? I would say that if you have comfort handling basic infectious disease, personal protective equipment, ferrets pose some risk – but I certainly wouldn't be opposed to handling a ferret. I have not had an opportunity to, but I wouldn't hesitate to do it, so I don't think we need to be banning ferrets. Some people have been pretty worried about that.
I think we have to be careful because of the mink story, but this is why we have PPE and this is why we have our infection control practices. I think if you're comfortable doing that, you need to be wary of ferrets but still treat them.
Other species – I won't get into that too much. We don't know a whole lot. There are a lot of experimental studies going on right now. Hamsters are susceptible. There are various other species you can see it in. Poultry doesn't seem to be an issue. Livestock so far don't seem to be an issue. There is some other stuff coming out on that. This really is focused around the mink story; that's the biggest one in the companion animals. Looking for reservoirs, looking for feral animals, what we don't want to see is this escape into wild mustelids or get into community feral cats. We don't want an animal reservoir, which is why we're trying to keep infected people away from animals as much as anything else, so they don't get the chance to do that.
From a clinical standpoint, when to suspect COVID? The big thing is knowing that household history, because if they're going to have clinical disease, they're going to have it right around that time that someone in the household is infected.
There are obviously asymptomatic infections in people and they can be infectious, so asking if everyone is healthy isn't going to get everything. If you have a household where there's no history of exposure and you've got a dog with respiratory tract disease or a cat with respiratory tract disease, I'm thinking about our normal respiratory pathogens. If you've got an adult indoor cat that never sees anyone else and has classic infectious upper respiratory signs, then yeah I'm a little more concerned, because I don't have a high concern about our normal respiratory viruses. We need to think about household risk, not focus completely on it, and then if it's a respiratory disease, GI disease, or combination thereof. If you see respiratory and GI disease in a low-risk animal from a COVID household, then certainly that's ringing some bells.
The risk assessment on the individual patient level – this is pretty straightforward stuff. From the household level, do they have known COVID? Do they have undiagnosed respiratory disease? Do you know nothing about them? Are they known healthy? That's our gradation risk.
Ferrets are probably higher risk than cats that are higher risk than dogs. We don't really know, but that's a reasonable assumption.
Then there's patient status. If they've got acute respiratory and GI disease, that's probably #1. Acute respiratory or GI disease (remember these are very common, and there are a lot of other things that do it) is something else to be concerned about. Healthy is lowest. It's just a matter of trying to figure out when we've got situations we need to take extra care beyond what we do. We do our routine infection control practices to protect us from unknown exposures, so our handwashing and our personal protective equipment used routinely are going to go a long way. I'm going to talk a little bit more in a bit about some of the PPE.
We've gone over testing a lot on the boards and in previous talks. For me, testing is interesting, but at the clinical level testing doesn't change what we do for the patient. We don't have specific treatments. We're not going to change management of that animal based on a test because that's not going to be 100% sensitive or specific, and we don't have antiviral therapy that we use for this virus clinically because we probably don't have clinical need to do that.
Since it doesn't change what we do with the patient, and if you're worried that this animal might have COVID, the best thing for it is to stay in the house. We really don't want him coming into the clinic just for testing for this virus. If we have them in there and we're evaluating a respiratory disease then we can start thinking about testing, but there aren't that many situations where testing is really going to help us at the patient level.
Sporadic testing – if 100 people test and we see X number of cats are positive, it's kind of interesting, but if I don't know anything about the 100 that were tested and who is positive and who is negative, it really doesn't tell us anything more. We know they're susceptible, so it doesn't really help us from a surveillance standpoint, as opposed to the studies we do where we go in and we target and we get data and we try to figure out how and why and when this virus is moving around.
Back to some of the transmission, because this leads into thinking about what we do in the clinic – there are lots of infographics like this.
At home – low risk. You're with your population. Outside is exceptionally low risk.
If you're a reasonable distance outside, you don't have to panic when someone is walking around the street with you – really low risk.
You start to get indoors. The risk gets higher.
You get indoors for long periods of time in a small room with poor ventilation, and your risk gets higher still.
This is all common sense. I'm not going to get into the masking side too much, because it's a very political issue in the U.S. and I don't want to go there.
I want to point out a couple of things. Masks are there for droplets. Droplets are the big concern for transmission, and masks can be a very effective way to reduce droplets, even basic non-surgical masks.
This is a preprint, but this kind of a good statement from here – whether mannequin or human, wearing a face covering decreased the number of projected droplets by greater than 1000 fold. This is a combination of experimental data and modeling. They estimated that someone standing 2 meters from someone coughing without a mask is exposed to 1000 times more virus than somebody standing 5 cm away from someone wearing a basic mask. Those masks are doing a really good job of containing droplets, and droplets are the concern. This is one experimental study. It doesn't tell us everything, but gives us more substance towards masks reducing droplets, and droplets being the big concern.
Really briefly on masks – I'm thinking about the different types of masks that we use.
N95s – Rarely do we need to use them. Maybe aerosol-generating procedures and high-risk animals. In human health here, they're backing off using N95s. At the start, it was N95s everywhere. Now they've realized the risk is mainly with aerosol-generating procedures, and even that risk is limited with basic practices. N95s are something we don't really need to use, which is good because they're hard to get. We want to save them for human healthcare. You need to be fit tested. They're uncomfortable to wear.
Surgical masks – they are predominantly designed to protect from us. N95s are to protect the user. A surgical mask will do a moderately good job of protecting the user. Largely we're using them to protect FROM us. In surgery, we're wearing a mask to protect us from depositing droplets on the patient. That's why we use them, and they are good at that.
Cloth masks are very similar to surgical masks, they're just not as consistent because they're not made to a set standard. A cloth mask has variable efficacy but if they're fit well, they're probably fairly effective.
You've seen things like this. Basically, the take-home is that if I'm wearing a mask and I'm infected, I'm doing a good job of reducing transmission. If I'm wearing a mask and I'm next to someone who is infected who is not wearing a mask, yeah it's helping me, but not as much as an N95 and eye protection. It's going to give me some level of protection, but I'm leaving my ocular mucus membranes wide open, so I'm not using it as a primary thing to protect me. I'm using it to protect others, and I'm hoping that they wear a mask to protect me. For two people close together not wearing masks, the risk is high. The farther apart they get, the risk drops. If the infected person wears a mask, the risk drops even more. That's the big thing. Masking is a community protection tool.
One other thing about masking, and I think people are starting to get this now. I see one airline, I think Hawaiian Airlines in the U.S., has jumped on this too – exhalation valves. I'm not sure if you can see my pointer, but on the bottom middle this is an N95 with an exhalation valve. On the right here, this is a cloth mask with an exhalation valve. Exhalation valves are there to make it easier to breathe out because there's no filtering of the air. If I'm using an N95 in a situation where I'm trying to just protect me, an exhalation valve is fine because it doesn't matter what's going out, but it does nothing to protect everyone around you.
This is a really crude experiment I did. I put on a cloth mask, a surgical mask, a regular N95 mask, and I breathed pretty heavily against the culture plate and nothing came through. I put on an N95 mask that has an exhalation valve and I breathed pretty heavily, and look at all those bacterial chunks that came through – and virus would be going there as well.
What we don't want to see is people wearing masks with exhalation valves, and you see a lot of them out there. They're available online.
If you're wearing masks in your clinic, you want to make sure people aren't using exhalation valves. I've seen them here. We've had to enforce people not wearing them here, because basically they didn't realize it.
It's difficult with clients that come in wearing this and how you address that. That's something to think about, but certainly it's easy to address with staff. This is not the type of mask that we wear because it doesn't do what we want it to do, which is to protect everyone else.
In terms of when to use different PPE, you'll be able to look at this after if you look at the recording. There's a document that has this in there. Basically, they're different situations in terms of the animal risk and the procedure that dictates PPE.
This is from a document we produced in Ontario. This is a best practice. It's a guideline document. I've got a new version of this coming out probably tomorrow. Hopefully it's going to be finished off by tonight or tomorrow. It's based on Ontario because that's where I'm making them for, so I based it on the stages that we're opening it up to, but it's focused on how do we maintain clinics. How do we start to open up, if you want to open up to people coming in, things about exam rooms and ventilation or flow. This will be on our Worms and Germs blog website probably tomorrow. This table is unchanged. It ranges from somewhere where you can't maintain 2-meter distancing – so just a regular mask, a regular PPE – down to the bottom one, an aerosol-generating procedure on an animal that can have COVID and has been exposed to someone with the disease. That's telling us it's compatible. You've got a cat from a COVID positive household. It's got respiratory disease and you have to be in its face for some reason. That's when I would go N95 if you have it, otherwise a surgical mask, and either way with a face shield. It's not a very common situation, so more often a surgical mask, a face shield if we need an extra level of protection, and then our routine PPE.
CDC has guidance out there too. It took them a long time before they actually decided to say anything about animals, but they've got some good information out there now. Their table is very similar to ours. They've got maybe not as much differentiation of the animal species aspect, but I think similar concept of when to pull out different types of PPE compared to what we have. If you just Google "COVID veterinary," it will come up. I didn't put the link on there, but it's easy to find.
If we start thinking about clinics, this is where you get into the communication aspect. It's not an airborne virus. Aerosols probably aren't a big deal. If we're expelling small droplets, it's probably not a big deal unless we're doing it for a long time in a closed space with poor ventilation. Ventilation actually does matter, because something that's unlikely or released at a low level gets more and more relevant the more it happens. If I'm breathing out and every minute I'm putting out a little bit of virus in small droplets, maybe that's not a big deal, but if I'm in a small room for 15 minutes talking and breathing, maybe that's going to amplify to enough that's a concern. This is where we start having to think about ventilation.
Ventilation is important to prevent accumulation of infectious particles and disperse clouds. If I'm talking or I'm coughing or sneezing and I give this big cloud of droplets and they're full of virus, I want ventilation to disperse that, dilute it, spread it away very quickly, or suck it up or suck it down if we're indoor. Really, we want to make indoors like outdoors, so we want a higher flow that doesn't let these things linger around.
There were various numbers tossed around. Essentially, the last thing I saw from the WHO was if your ventilation is less than 3 L/person/second, your risk might be really high. Ideally, we want to be at 8 to 10 L/person/second. Ideally, we want to have limited recirculation because if you're just moving that air from the room into the ventilation right back down into that room you're not doing a whole lot, so we want to limit recirculation within the confines of your ventilation system. If it's -20 outside, your system probably can't keep up with no recirculation, but we want to get the airflow as much as we can and bringing as much fresh air as we can – especially in places where there is greater risk, so exams room again and places where multiple people are going to be and that might be for a long period of time.
That always leads to questions about filters. There are a lot of companies trying to come up with a market for devices.
HEPA filters are not going to hurt. Any type of filtering isn't going to hurt, but it's probably not going to help a whole lot. An in-room filter might be useful. Some of these small portable filters are going to suck air through and run them through a HEPA filter. If nothing else, they're providing good ventilation. They're moving air around a lot more. They're dispersing things. The air they suck in, the HEPA filter will pull out some virus.
These are kind of cheap and easy and they would make sense. Putting HEPA filters in your ventilation system is expensive, there's probably not that much virus that's getting into your ventilation system, and bumping up your airflow and limiting your recirculation probably is as effective (or more effective).
There are other things you can do, like UV light in ducts. CDC's line with UV light is that we don't have any evidence of efficacy and it's potentially harmful. It's one of the ways that get described is if you've got enough UVC in a device to kill the virus, you've got a risk to you potentially unless it's a really good device. UVC is quite toxic. It does a great job of killing viruses. It does a great job of messing up DNA. You can have devices that will suck things through in a UV. You can have things that when you leave the room, the system comes on, but it's really just difficult to justify. Improving ventilation is going to be much better than worrying about other filter things. If anything, you could have an in-room HEPA filter device, and some of these are ultimately inexpensive. It can be useful in some ways. It makes people a little more comfortable as well.
We talk a lot about bubbles. You're bubbling with whatever groups. We're trying to keep the number of new contacts down. That relates to one of those earlier slides. If I see X number of people, what are the chances one of them is going to be infected? As that number gets bigger, my risk goes up. If I limit my contacts to a defined group of people that are limiting their contacts to that same defined group, then we can reduce the risk.
That's where you get into discussion of "Can we do a clinic bubble instead of masking? I've got X number of people in my clinic and we're going to decide that we're going to be a bubble, and we're not going to mask. We'll mask around clients, but we're not going to mask around each other because we're just considering ourselves one unit." It's certainly a possibility. It works better if the prevalence is low in your area, but the problem is you're relying on everyone to do things right. If one person in your bubble goes out to parties and bars, your bubble is kind of screwed.
The other aspect there is rarely do we have one bubble. I could have my clinic bubble, and then I've got my family bubble, and my kids have their friend bubble, and there's a school bubble, and we're just one big toxic bubble bath eventually.
The bubbling concept makes sense. In application, it can be a bit of a challenge. It's certainly something you can think about in your clinic. Smaller numbers is better. You've got to be really confident in your staff. All it takes is that one person messing things up, because if you've got one person in your bubble that's infectious and you're not barriered, that's how you get the whole clinic infected and shut down. I know of a reasonable number of clinics that that's happened to, especially early when no one was masking. One person brought it in, infected everyone else, and the clinic is closed for a while because everyone is home isolated.
You have to have good conversations with your staff if you're going to do this. You need to make sure everyone is being responsible. You need to make sure they don't have a lot of other bubbles that are causing risk, and you just have to realize that you're increasing your risk if you do that.
Clinic makeover – we don't need to be doing really complex, expensive changes to clinics to improve things. There are some really basic concepts that we're trying to achieve, and we're trying to balance things. We're trying to maximize containment and safety and comfort for our clients and our staff while making it practical, making it economical, and being able to run a clinic like a clinic. It's not going to be the same. We're not going to be the same for a while, but close enough to the same so that we can treat animals, make sure clients are happy, make sure the economics are still there, and make sure we can do our jobs. It's a fine line – so how to do that?
When we start thinking about some general concepts I'll come back to in a minute, one of the questions that comes up all the time is, "When should we let people in the clinic?" Or, "Can we let people in the clinic?" A lot of people still aren't. Some people are wide open. It really depends on a few things.
Knowing your regional risk – the more COVID in your area or the less you know about your area, the greater the risk.
Clinic personnel risk factors – if it's your clinic and you're 65 and you have diabetes and you have asthma, probably you're more reluctant to bring someone in than if you're lower risk. If you have people that are high risk with serious disease, we need to think about that because the implications of bringing something into that clinic to that person might be really severe.
Your clinic layout – are you able to make some changes that can reduce the risk? Do you have space to spread things out? Do you have good ventilation? Can you switch your flow or are you going to be a really dense practice the minute you open that door, which is going to increase your risk?
Climate – it's -30 outside. Up here it's snowing and windy, and it's kind of hard to have people hanging out outside. We can still do things. We can wait in vehicles. Thinking about practical aspects for clients is obviously as important.
The practicality of alternative approaches – is curbside delivery something we can maintain? Curbside drop-off of food. How difficult is it to do?
Staff comfort – this comes down to a lot of staff are still really wary or are scared. We can balance some of that by education, but we have to consider that.
Really, you have to pick your battles. We've got a whole range of things that we can do. The more things we do well, the more things we can skimp on. The more that we mask, the more that we distance, the more that we avoid high-risk activities, the greater the risk we can have schools open. It's not all or nothing, and it's trying to do as much as we can to maintain as close to normal as we can. Staff comfort has to be part of that equation. Part of it is your ability and your willingness to enforce rules, too.
If we're going to bring people in the clinic and you know you're going to have some compliance issues the way you're set up and no one is willing to enforce that, that's going to be a challenge.
If you look at our main goals, what we want to do is limit the three Cs (or the four Cs with a time component). We want to limit the number of contacts. Every human-to-human contact poses some risk. The longer it is, the closer it is, the less barrier there is, the risk goes higher, so we want to limit the number of people that are ever in the clinic, and we want to limit the number of people that are in the clinic at one time. More people in the clinic means more exposure of us. More people in the clinic at one time creates risk for them, but also potentially increases that amplification effect of the virus.
We want to limit contact. Having people in the clinic is one thing, but we also want to keep them away from us and our personnel and each other as much as we can.
Limit those contact times and maximize barriers while still doing our jobs as much as we can. It's a balancing activity.
These are some examples. These are pretty straightforward, and probably most of you are doing most of these things.
Lobby or reception – hand sanitizers, masks at the entrance. I strongly recommend a mandatory mask policy. Here it's mandatory I think pretty much the whole province now – a mask anywhere for indoor spaces. It's easy when it's mandated. It's normalized. In areas where masking is mandated, it's easy because it's just normal. It becomes a social expectation. It's more of a challenge in areas where it's not required, and then you've got I think more confrontation that happens.
Rework your layout to encourage one-way flow and maintain separation. I'll come back to that in a little bit. Run your clinic like your grocery store. Grocery stores tend to do a pretty good job of this. You've got arrows, you've got barriers to set up one-way flow, and you've got Plexiglass to keep you from breathing on your front office staff. You limit seating. If you only have two chairs in there, you're only going to have two people sitting down, so thinking about maximum occupancy rates; one person for every 10 square meters is kind of a standard thing in a lot of areas. That's not that many people. Think about how many people you could fit in an area, so look at your lobby and think how many people can be in there and maintain 6-foot distancing without having to play a game of Twister any time someone has to move from one place to another. In most clinics, you're not going to have that many there. You take out some chairs, you put in some barriers, and you make it clear that we don't have lots of seating space.
Distancing front office staff from each other – if we've got two people working at the front office, we don't want them sitting 3 feet apart. We want them sitting 6 feet apart or farther, or one in another room if it's possible.
Exam rooms – for me, I think exam rooms should be client-holding rooms, not exam rooms anymore. For me, the perfect appointment is if you've got someone that has to come in, they come in, they go right to an exam room, you come in and say hi, how are you doing, you take their animal, and off you go. We've figured it out by phone. We've had some remote discussions or maybe I'm going to have a quick distance conversation with you because I can maintain distancing, we can have a quick chat, we've got a mask on, and we're not getting into that few minutes' conversation time, take the animal back, do the thing, bring it back to the owner and bye, see you later. Bill them out or whatever you have to do. We're limiting contact time. We're limiting closeness.
If we're doing exams with owners there, almost inevitably someone is going to come up. Right? They're going to help or they're going to come and stick their face in there and all of a sudden you're breathing on the person. You're not at a 6-foot distance.
Think about as much as we can do to separate owners from all the things that we do.
Treatment areas, so the back end of the clinic – just thinking about how we move through them and where tables are, where materials are so we're not walking by each other all the time. Think about how many procedures that can go on. It's not that hard to do. It's just a matter of stepping back and looking at it and thinking, okay, what can we do here and here? In different scenarios, what would we have to do to reduce the risk?
Exits – In some clinics, you can have a really nice one-way flow where they come in and they never turn back in that direction. In some you just can't. If you have one door, you have one door. Think about how we can prevent cross-contact of people with staff and with other people, and bringing in things like remote billing so they don't have to come back, or billing in the waiting room so they don't go from the waiting room to an exam room, back to the waiting room, to the front desk, they just work their way through.
Again, that's really just having a look at your clinic. I'll come back to that really quickly.
Like I said, a lot of the transmission in human hospitals happen in lunchrooms or break rooms where people let down their guard with their PPE. Think about offices and lunchrooms and how to separate people, and how to time things so people aren't hanging out (especially for long times) together, and barrier.
Reducing staffing numbers – I'm not talking about fewer people working. We're talking about fewer people working in the clinic at the same time, or fewer people working in the same room. You can still have people that are working, but we've got them spaced out differently. We don't have congregation sites. We've got people that are working but aren't working in the clinic – people that are doing management activities, people that are doing phone followup phone calls, doing telemedicine, doing records time. There are some IT issues trying to do that, but the more we can move people out to their homes or to other rooms, then we could still have people working the same amount of time doing the same amount of care without having them creating a risk in the clinic, so think about how we can maintain some degree of remote working.
Telemedicine is obviously a huge topic. It's great for a lot of things. Limit the number of patients you see. Limit the number of visits that require someone to be there. We can get hybrid appointments – I'll mention that in a second. We can reduce the number of people that come into the clinic, the number of animals that come into the clinic, and the number of vets that have to be in the clinic at any given point.
Obviously, we can't do everything by telemedicine. We need to see some animals, but even in cases where we need to see the animals, this is where hybrid appointments come in.
For a new puppy visit, you've got one vet who is working Monday and they're doing telemedicine and we've got a few new puppy/new kitten calls. You do the new puppy call, you talk about nutrition, you talk about everything else, you figure out what health problems that are there, and you get all that discussion done where you need the owner. Then they do a curbside visit which is a quick drop-off, a physical exam, everything is good, vaccinate, send him home with some stuff, and off you go. We've had that communication with the owner. We've had the good level of care, but we kept the owner out of the clinic and we've had a quick visit.
These are the types of things that we have to be creative with.
Whatever you're doing, we can do risk assessments. If you're doing curbside drop-off, the risk is low. We've got a very short time of contact. We can get barriered. We can wear masks, we can have hand hygiene. We can keep that exceptional low risk.
With people waiting in the reception area the risk is variable, but it's potentially high if you have a lot of people with poor ventilation and they're there for a long period of time. If we have to, we think about masks and ventilation and barriers and flow and distancing, but ideally we don't have them there. If you're starting to bring people in or if you are bringing people in or you're doing different types of things, just sitting back and thinking about the risk and the preventative measures for each one of those individual steps is useful.
An exam room is a really hot, closed space, close contact, potentially prolonged time, droplet generation activities like talking – so again, use exam rooms for client holding and not for exams. Bumping up the ventilation, wearing masks, distancing as much as you can, trying as much as we can to prevent the clients from holding the animal and things like that. Minimizing that close prolonged contact.
I said this before – the ideal thing for me for an exam room is the client goes in the exam room, we get the animal, we have a little chat, take the animal back, do our thing, and come back. We can explain things, you can demonstrate things, you can show things, and that might only take a minute as opposed to that 15-minute exam. If we need to demonstrate something, if there needs to be any restraint, bring someone with us so the client can still be at the back side of the room. You can show the things without creating risk.
This doesn't really decrease efficiency. I think it makes a lot of sense.
We've got some people saying, "Well, this is weird. Clients are going to think it's weird. They're not going to like it." Change is hard, but it's normal. It's going to be normal. This is an example from dentistry. If we talk about telemedicine being hard in veterinary medicine, for me with telemedicine dentistry I have a hard time figuring out how it's done, but they're talking about it. They're doing teledentistry, and they're starting to do more of that.
There are a couple of comments here that basically are the same as what we're saying. The reason I'm saying this is that it's not going to be, "Oh, look at this crazy thing my vet's doing." It's, "Well, my vet's doing the same thing as my doctor and my dentist," or "Why are my doctor and my dentist doing this and my vet isn't? That doesn't make a lot of sense." The notion of sitting in the waiting room these days is largely done.
To maintain social distancing, dentists are having to rethink what things look like. It's reduction, and some have removed chairs from their waiting rooms. It's changing how we think about staff and patient flow through an office. It's exactly the same thing we're talking about.
We aren't going to be abnormal or strange. I think if we do this, we might be abnormal or strange if we don't.
Just to wrap up here, and then we're going to do some questions – this is a drawing I pulled off the Internet. I have no idea whose clinic it is. It might be yours. It's an example of thinking about what we can do. Every clinic is different, so you really have to think about your clinic. I'm happy to chat with you about your clinics.
Think about how we move people through and move animals through.
What usually happens? Someone comes in and they check in at the desk. They go to the scale. They hang around the waiting room. They may go back and check out things. We've got a lot of movement there.
The technician comes in, maybe checks into reception, gets the record, maybe comes in to say hi, how are you doing, and go into the exam room.
Then we've got another person that's coming in at the same time, and they're doing the same thing. The more overlapping arrows we have, the more transmission risks. Limiting the number of people that come into the clinic, through curbside, through telemedicine, prevents some of that crossing. Limiting the number of people that come into the clinic frees up exams rooms so we don't have the people waiting around, so we can be servicing the same number of clients or have fewer of them in your rooms.
Instead of that happening, someone comes in, they check in at the desk, okay, they've got Plexiglass here, wash your hands, wear your mask, and go right in the exam room. You bypass anyone. You're there by yourself.
The technician comes, says, hi, how are you doing. Hopefully, we've got your record. Maybe we've got it from telemedicine or a phone call, or I'll just ask a few questions here. You can stay in the corner. I'll stay here. We're going to go back, do what we need to do with Fluffy, and then we'll drop it back off. Maybe we'll bill you out here. Maybe you'll pop back to the reception.
This is where I come back to clinic flow – go to the reception, and maybe you head out the side door, or we bill you out in the exam room, and you go out the back door.
We're trying to figure out how we can make things efficient, make things easy, reduce the amount of time we spend with people and the contact we have with people. I've been in enough clinics where you look at it and say, "We can't do everything perfectly, but we can always do something." I have yet to see a clinic where we can't do something that makes sense and isn't disruptive. This is where you need a fresh set of eyes. Sometimes bringing in someone new is good. Sometimes it's just a matter of separating it from your normal daily activities. Don't try to do it for 30 seconds or think about it when you're doing an appointment. Take some time – five minutes – and watch how things move. How can we do this? Or ask a client. How could we do this to make things easier? What does this seem like? I think we can make some logical changes to our clinics.
With that, I'll head into questions. We're a couple of minutes over here. I'm always happy to answer questions. There's my email. You can get me through the boards as well. If it's something that's urgent, put urgent in the title. I get a crapload of emails, but I try to reply to any clinical questions, infectious disease questions, and COVID questions as quick as possible. If you don't hear back from me quickly, send me another email to chase me because I may have just missed it, but don't hesitate to email it if you have any questions.
If you do have any questions, toss them in the chat. There are some there right now. I'll start going with those, and if there are any others we want to add, jump in as we go.
Q: You may address this tonight, however a main question I have is in regards to best practice and fomites. We are doing curbside. We bring animals in from the parking lot. Cats are in carriers, dogs are on their leashes. I have heard some people bathing animals when they come in. I don’t find it to be super practical. Things that seem manageable would be using our own leashes etc. Curious to get your expertise. Thank you for putting this on tonight!
Scott Weese: Fomites – I didn't get into fomites. Yeah.
Is there a risk of coat contamination? Sure. Is it a big risk? Probably not a huge risk. Like I said at the start, fomites are a potential source. Your dog and your cat are just like your cell phone and your chair and everything else. If I'm infected and I'm coughing and sneezing on my cat, there's virus on my cat's hair coat. How much virus is there, how long it stays there, and the clinical implications of that are the big questions.
We talked about things like bathing, wiping them down with a biocide. We just don't know. We don't have good evidence that fomites are an issue. I think we're getting less and less concerned about fomites being an issue over time. If we bathe them, we're increasing the contact with them – so is that good or is that bad? It's an easy-to-kill virus. A soap bath will definitely do it, wiping them down with a biocide wipe will do it, chlorhexidine rinses, all these things will do it. I wouldn't do that as a routine thing. Where the real concern comes in is you've got this cat that was sitting on its owner's lap, and this owner has active COVID, and they've been coughing on the cat, and then that cats make it into your clinic right away. The cat's gone from the owner to you in 20 minutes, so there's a plausible chance. This is why we flag high-risk situations, and this is why we've identified COVID in the household. We're going to wear gloves, we're going to wash our hands, and we're going to have PPE on.
I think our routine practices are probably good enough. If we're worried about it, wiping them down with a biocide wipe makes sense, but I don't think I would go to an extreme. I think I'd back off. Like I was saying, yeah, you can go ahead and try it. "It may not hurt" was maybe my line a few months ago. Now it's like, "Yeah, I probably wouldn't bother." I think you've got to focus on our good practices. If you know the owner was sick and they and they were really sick and they're coughing all the time and their cat has spent all day in bed and it's coming with them and it's coming right to you, then that's a high-risk thing. I would consider wiping them down, but I wouldn't do that routinely, and I wouldn't get into anything more than that.
Good question. Who knows? The risk is probably low. We know dogs can get infected with this virus. There's no doubt about that. Experimentally, they don't shed much virus and for long. One of the Hong Kong dogs that was followed, they were able to isolate virus, so it was infective virus in the dog's nose. That's a plausible risk.
I think the practical risk is probably much lower in a dog than a cat or a ferret because they just aren't very susceptible hosts. They can get infected, but they're not good hosts. They don't get a lot of virus there.
Q: Can a dog get it from another dog in a daycare or dog park setting?
Scott Weese: I think if your dog is going to get it in the dog park, it's going to get it from an owner and not the dog. My biggest risk would be the dog is running around with another dog and then it goes and sees the owner, and the owner says, "Hi, nice doggie" and touches his face. If that owner has COVID (which is how the dog would have COVID, right?) that's probably a greater risk than getting it from the dog.
It's one of these things where the risk isn't zero, but it's very low.
Q: What about insects (mosquitos, fleas etc)?
Scott Weese: We don't really have much concern about them, or realistically any concern about them. Is there a theoretical risk? Well, yeah. A fly lands on my nose and gets some secretions and he goes and flies up your nose, yeah, but in the real world, no. We're not really worried about those.
Q: If seroprevalence is 14% in feral cats (Wuhan), how likely is it there is already a reservoir established in feral cats in Wuhan? Is there any serosurveillance underway of feral/shelter cats in US cities with high rates of community transmission?
Scott Weese: That's a great question. Transmission is one thing. Sustained transmission is the other.
I've heard of some being done in the U.S. We're doing some in Canada. I think the risk of sustained transmission in feral animals is probably low because they've got a fairly narrow window when they're shedding, so this isn't a virus where you're infectious for weeks or months. You've got to be transmitting that over a very short period of time. This cat has to get infected, and then within a few days it has to infect another cat that then in a few days has to infect another cat. It could get into a colony and burn through a community cat colony. It's probably going to burn through that colony fairly quickly. If there is some protective immunity (which there seems to be from one experimental study), I don't think we have enough big feral cat populations where we would see sustained transmission – I hope. That's why we're looking at the feral animals. We want to make sure that that's not the risk. I think the risk probably is low because your average feral cat community is relatively concise. There are certain other species where they've got a lot bigger population or they've got populations that move between each other – I think there would be a bigger risk.
The bigger concern probably for feral cats is short local epidemiological issues. An indoor/outdoor cat gets infected, it goes and infects the colony of cats, so those cats expose other cats who could maybe bring in another household, but that's going to be in close confines. I think there's potential concern there for local short-term things, but I don't think we're going to have an issue where it's being maintained in New York City despite being eradicated in people because it's circulating the feral cat population. I just don't think there's enough fuel for the fire. It's a pure guess, but I don't think there's enough fuel for the fire to keep it there long term.
Q: Where can one find this data (RT, % per meeting 100 people, etc.)? This is incredibly helpful to assess county risk.
Scott Weese: You just have to look around. Twitter is an amazing source for some of this stuff. There is some really good medical Twitter information. There's a lot of good surveillance stuff that comes out, but I think you have to look in your area. Some states put out information. Sometimes you have academics or biostatisticians that put out information. Like I said, in Ontario, we get information from the government, but a lot of the data I put from that one person on Twitter, he's a biostatistician who takes all the data that's publicly available. Some places in the U.S. you can get really good data, and some you can't. Essentially, you've got to troll around the Internet, and look at your local public health unit site. You can get that broader data on that Statnews site and other places like the Johns Hopkins. You can see higher levels – overall numbers – but if you really want to get that refined, you need to find someone who is taking the data and crunching it.
Q: Also, so a staff member who is a college student, when they are contacting a lot of new people at the school... Make them wear a mask 24/7 and avoid break room, or not even in clinic?
Scott Weese: I guess the higher risk they are, the more important the preventative measures are. This is where you get into that bubble. You certainly wouldn't want to have a bubble with someone who is a student that's hanging out with lots of new people at a college or university. I think that you really should be considering masks all the time in the clinic, cloth masks, except when you're by yourself if you're in your own room. Anytime you're with someone else, I think we should wear a mask.
If you've got a high-risk person like that or if you have a really high-risk person for getting seriously ill, then you really want to emphasize mask use.
"Not even in the clinic" comes down to how risky they are. I think it's talking to them. Some people will get it and some people won't. It's how much risk you are willing to accept. The more people they contact, the riskier behaviors there are, the more risk they pose to your clinic. Masking will reduce that risk. Distancing will reduce that risk and won't eliminate it. It comes down to that personal decision in the clinic.
Q: Would there be a risk of releasing a mink (in captivity in rehab) to the wild that was in rehab with someone exposed to COVID?
Scott Weese: Yeah, I certainly wouldn't want to. The good thing about wild mustelids is they don't tend to live in really dense populations. We're certainly worried about that from mink farms because mink escape not uncommonly. There are enough non-wild-type mink coats that are out there, you know these are from escaped domestic mink. That's one of the bigger concerns is really focusing on biosecurity on mink farms, not getting out there and infecting wild mustelids. I think any animal that's being rehabbed with someone with COVID, I would not release it until at least 14 days after its removal from that person or 14 days after that person was deemed negative.
Fourteen days is kind of a guess that it would behave like any other species. If it's a raccoon, we know nothing about raccoons. I really don't want raccoons. We've got more raccoons than people in a lot of cities around here, and that's a population I'd be more concerned about based on their density and their social behaviors.
I think any rehab species, if you have a person that's infected, I want them quarantined. We talked about it in community cats too. Any community cat caretakers, if they're sick, we really want them staying away from their animals. We don't necessarily think about this, we might think I've got COVID so I'm staying away from people and I'm doing a really good job. This community is just down the road a little bit. I'm going to go out and I'm still going to do whatever. Now we really don't want that happening, because we don't want to get exposure.
Q: What if everyone in your work bubble wears a mask with an exhale valve? They aren't protecting you, but you are protecting you, etc.
Scott Weese: Well, then no one is wearing a mask basically. You're getting a little bit of protection from them because your mask is helping a little bit, but remember your mask is protecting your nose and your mouth and not your eyes, so if you're encountering infectious aerosols, you're only doing part of the job. Masks will do something, but they aren't there as the primary protection tool. The primary protection tool is preventing aerosols and droplets from being generated. If everyone is wearing a mask with an exhalation valve, you're not doing a whole lot. If someone is wearing an exhalation valve, they're protecting themselves a little bit, but they're not protecting you. That's why we just don't want these anywhere.
I flew through all this stuff pretty quickly, so I'm happy to answer any of them. Hang on.
Q: I had to run after a crying child, so I may have missed this! If doing curbside, and you bring a dog into your clinic, would you put on a clinic leash or leave the dog's leash on. May seem silly, but it's something my staff is pushing hard on. I am happy to do what is reasonable and safe!
Scott Weese: Yeah, the clinic leash question. I get this all the time. What is the risk of the leash? This is cost benefit. The risk of the leash is probably pretty low, and this is why we do our routine things. If we're wearing gloves and we're washing our hands and we're querying health status... if the dog is from a household with COVID, the leash is high risk. If the dog is from a household without known COVID, the risk is low. Someone would have had to deposit something on that leash, probably right before it came. Yeah, they could be an asymptomatic carrier, but the risk gets lower and lower. It's cost/benefit. If you can do the transfer – if it's effective, efficient, it's something that works in your system – switching leashes is fine. If it's a situation where you've got an animal where it's going to create a risk of losing the animal or it takes more time, you spend more time in that person's face while you're changing leashes, so you're probably not helping yourself out.
I don't really have a firm line on this. I think it comes down to switching leashes probably confirms a little bit of a benefit, but if switching leashes makes it more likely you're going to lose an animal or you're going to spend more time with the client, then you lose that benefit. If we wash our hands and we wear gloves... if we've got higher risk situations, we'll have to wash our hands, not stick the leash up your nose, and we're probably good. It's a pretty minimal thing for me.
I think we might have gotten through them all. Like I said, I'd be happy to take any of the questions. Anything on the boards, we'll hit back up. Send me an email if you have any questions. With that, Carla if you have anything to jump in on?
Carla Burris: I was just going to say a big thank you for spending some time helping us wade through all of this tonight. Thank you to everyone for your time, and have a lovely evening.
Scott Weese: Great! Thanks everyone.
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