Making Sense of the Source and Transmission of COVID-19
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FIONA POWELL: The fault, does not lie with animals, says Bucknell, doctor DeeAnn Reeder, a leading bat biologist and expert in white nose syndrome, rather emerging infectious disease outbreaks have been exponentially increasing in recent decades due to changes in human behavior including ecotourism, exotic pet ownership, and the loss of biodiversity among many other things. I had the opportunity to speak by phone to Dr. Deann Reader recently and she outlined the origins of the novel Corona virus that causes COVID- 19 and our possible new normal.

DR. DEEANN REEDER: My name is DeeAnn Reeder. I'm a professor of biology at Bucknell university and I'm a wildlife biologist who studies emerging infectious diseases that come out of animals. The reason that's relevant to understanding COVID-19 is because all the evidence strongly suggests that this is a zoonotic pathogen causing this disorder. So what does that mean? Let me start by saying that the majority of emerging infectious disease outbreaks all around the world originate in animals. That's what we mean by the genesis of a pathogen that is able to jump from animals to people. And we call that jump a spillover event. And some of these pathogen sources are domesticated animals like pigs and chicken and cattle and goats and sheep, but most outbreaks actually originate in wildlife species. And that's what I study. In the case of the current pandemics, the molecular studies of the gene sequences of the virus that causes COVID- 19 strongly suggest a bat origin.

Getting to the question of how do we know that there's a bat origin, right? Just have to say that, but what does that mean? What kinds of evidence do we have? You can create what we call a phylogenetic tree or sort of a family tree for everything living, but you can also create one of those for viruses and you can include in that family tree of the virus that causes COVID-19 and it turns out that this virus sits within the branches on that tree that are all occupied by virus sequences, isolated from different species of horseshoe bats. Some reports have suggested that a second type of mammal, which is called a pangolin, not to be confused with penguins, the birds, but pangolins, the mammal, but that type of male could be the source of the virus or could somehow be an intermediate link between bats and people.

Most people have no idea what a pangolin is or at least before COVID-19 they'd never even heard of them. They were unique and critically endangered lineage of scaled mammals or scaly mammals that are found in Africa and Asia. I always sort of describe them as an Armadillo on steroids. We have found closely related corona virus is in pangolin and it's also the case that pangolins are prevalent in the illegal wildlife trade, especially in Asia. In the illegal wildlife trade are prized for their meat and for their scales which supposedly have some medicinal properties. In fact, they are the most trafficked animal in the world. It's also possible that the virus that causes COVID-19 is recently mutated or recombined virus originating in wildlife or one bat species to the next. The closest strain that we have found of this virus in animals, probably dates about 50 years ago.

So there's a gap. There's pieces of information that we don't know. We don't know where it was in an animal exactly in a bat or a pangolin just before this outbreak happened, but there's precedents for these kinds of genetically combination of viruses happening in other emerging infectious disease outbreaks. So it's possible that this is some sort of a hybrid virus and we will find out more with time. What I think it's really important is to know what else is in this viral family tree. So there's a virus called SARS corona virus, and for those of us who've been around for a while where you would remember that that caused the SARS pandemic in 2002 and 2003 and in fact the virus that causes COVID-19 is called SARS coronavirus too. And I think because the media has not been calling this virus by its official name, I think people haven't been understanding how closely related it is to the virus that caused the original SARS pandemic.

SARS was defeated in July of 2003. It was more deadly than COVID-19, but we think less contagious didn't spread as far and we weren't traveling as extensively at the time. There's a number of reasons why I think SARS was shut down in a way that we've not been able to with COVID-19. But one of the pieces of good news in the fact that we know that the current virus and the original SARS virus are closely related because scientists continued to study that SARS coronavirus in the interim. So SARS went away in the human population 17 years ago, but scientists still continued to study the SARS coronavirus and other related corona viruses, including the virus that causes MERS, middle east respiratory syndrome, and they repeatedly warned of the potential for another coronavirus pandemic to emerge. Now, before SARS, people didn't really worry too much about Corona viruses.

We really didn't study them extensively. We knew that there were several strains that had been identified that caused the cold, but they really didn't get any attention on the global scientific stage until SARS happened, and then MERS happened and so corona viruses in the last decade or decade and a half have really emerged as a group of viruses that people had been studying extensively.

Bad news is that when we repeatedly warned that, as scientists, that there was a potential for another coronavirus pandemic emerge, it was largely ignored by the world, but the good news is it's a work on potential antiviral drugs for corona viruses like those that cause SARS and MERS and antiviral drugs for other viruses as well, including Ebola and HIV. Work on those and potential antiviral drugs has continued and because of that we have a number of candidate treatments available now for testing and some of these are drugs that have already gone through human clinical trials for other purposes and so could potentially be rolled out as soon as we have some evidence of efficacy and others are similar in the pipeline of being tested. But the fact that we have multiple candidate treatments is really good news in our fight against COVID-19.

POWELL: We know that this is a zoonotic disease and we got it from animals, but zoonoses implies that it can go back and forth and we can give it to animals as well, doesn't it?

REEDER: It does. We call that a reverse zoonosis or a spill back and that's always a risk. I think we don't understand the degree to which that is a risk for SARS coronavirus Two, but I think that it's a significant risk. We know that with the original SARS virus 2002, 2003, that there were a number of reverse zoonoses. There are some concerns of reverse zoonoses for example, from bat researchers all around the world, including in the United States potentially working in the field while they're sick and exposing our bats to this coronavirus. Bats in North America are already just reeling under the effects of white nose syndrome. This emerging infectious disease of bats, this fungal pathogen that killed millions and millions of bats in the last decade.

We don't want to add insult to that injury by potentially giving them another pathogen that that might be detrimental to them or even worse, we could give them a pathogen and that virus decides that it's perfectly happy to live with them and it doesn't make them sick and then they actually can serve as a reservoir. So I think some real concerns are starting to be raised amongst those of us who study wildlife, about the potential for it to just go back into wildlife species all around the world. And then of course we're all really a little bit worried about our own dogs and cats.

POWELL: Could it jump from humans to farm animals and therefore into our food system or wouldn't that be a great concern because presumably if we consume an animal because this is not the kind of virus that will affect us by eating it.

REEDER: Right, exactly. So, a couple of things there. One is that corona viruses in general have what we call really wide host breadth. So corona viruses only like to infect one or two species. And they only have the ability to bind to the cells of very specific species. And other pathogens are really quite good at infecting lots of different species and corona viruses are in that group. So there is a potential that a number of different types of animals could become infected by this pathogen.

And you know, I know already the biomedical work is being able to show that primates can be infected, ferrets can be infected. I don't know that anybody has done any testing in domesticated animals as well. I think that there is absolutely no risk to our food chain in terms of people getting sick from domesticated animals that might have this because it's not something that is ... it's not we'll call a fecal oral transmission router. It's not going to ... by eating it, we're actually completely destroying the pathogen. So that's not a transmission route or this pathogen. The risk I think would be that if it gets into pig farms or chicken farms or so on, and then you actually might have people being sick as well, that affects the health overall of our domesticated animal populations. And then bio security that is associated with that.

POWELL:So we might see this as the beginning of a new normal, although as you said, we've had zoonoses for a very long time. It's just that it, this coronavirus is a new type of coronavirus, which is why it's called novel.

REEDER: So this is novel and it's really important that we think about it in that way because most people and most animals will have no preexisting immunity to this pathogen. So that's really the concern with novel pathogens that it's literally sort of we say come out of nowhere except that, that we're pretty darn sure which emerged at some point out of bats, maybe through an immediate host of some sort, but it is novel to people and to other animals that it then might spread to and when you don't have a herd immunity ... So once you have a pathogen in a region or an area, and most of the individuals in there have already experienced that pathogen, it looks very, very different. So two years from now, I think this is still going to be in our human population, but it will look very different.

We hopefully will have developed herd immunity where enough people are immune that it sort of keeps it from circulating. You know, sometimes I feel like chicken little, like I'm just always, and other colleagues who did the same work, we're just sort of feel like we're always out there saying these are huge risks, nobody's listening. We're not prepared. We have rolled back pandemic preparedness in this country over the last few years in really dangerous ways and Ebola wasn't enough to scare us.

There's still Ebola outbreak raging in democratic Republic of Congo and yet nobody's even talking about it anymore. We sort end up with this news fatigue. So we have these things, they emerge, you get all these little pictures every year at state fairs and you have Lyme disease outbreaks, but until it happens to someone, you know, I think it just doesn't become personal enough to internalize it and think that we have to change what we're doing. I think in the case of COVID-19 that we're going to get to a point pretty quickly where everybody knows somebody who's had it or been sick or God forbid has died from it. And I surely hope that the world will wake up to the likelihood of future emerging pathogens. Need to recognize the new normal, that the way that we live on lives makes it much more likely for pathogens to emerge. And so we have got to be absolutely ready for the next pandemic.

POWELL: Dr DeeAnn Reeder, professor of biology and animal behavior at Bucknell university.

Dr. DeeAnn Reeder was one of the panel who spoke during the recent Keystone Edition Television broadcast on Covid-19. You can watch the show here.