Consider This from NPR - Bird Flu Has Jumped To Cattle And To Humans. What Are The Potential Risks?

Episode Date: April 4, 2024

Bird flu has spread to cows. And now a human has contracted the virus from an infected cow. What kind of risk does this virus pose to people, and are we prepared to treat it?Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Ever since March of 2020, it's easy to feel suspicious of every cough and sniffle. COVID has left lots of people with anxiety, worrying that the next virus could be worse. So news this week raised red flags that a strain of bird flu spread to cattle and has now been detected in a human. Anytime there's a human case, it's of course concerning. Louise Moncla is a virologist at the University of Pennsylvania. The infected person in Texas came in direct contact with a sick dairy cow. It's still unclear how far it may have spread across dairy cattle in the country, but cases have been reported in Texas, Michigan, Kansas, New Mexico, and Idaho. I'd be very surprised if this was not being spread from cow to cow.

The way it's acting, the way people are telling me it gets on their farm and moves. But the big thing to note is we're not seeing mortalities with this at all. That's Joe Armstrong, a veterinarian at the University of Minnesota, who's been tracking this bird flu outbreak in dairy cows. This is the first time H5N1 has been found in dairy cattle, according to the American Veterinary Medical Association. We haven't seen this bird-to-mammal spread in an agricultural setting. Should we have expected it? Possibly. Joanna Harvey is a postdoctoral researcher at the University of Maryland. The virus wiped out massive poultry populations in 2022. And this year, CalMain Foods, the largest producer of fresh eggs in the U.S.,

has temporarily shut down after detecting the virus in their flock and depopulating roughly 1.6 million birds. Harvey says with cattle, and now at least one human being infected, this may not be the bird flu we've seen before. There are distinct changes in this virus that have facilitated what we see as increased global spread and species impacts. Consider this. What kind of risk does this virus pose to people, and are we prepared to treat it? From NPR, I'm Ari Shapiro. It's Consider This from NPR. Bird flu has done enormous damage to poultry and wild bird populations. Now it has been turning up in cattle across several states.

And in at least two cases, humans have been infected. Officials at the Centers for Disease Control and Prevention are working with state health departments to monitor this. And CDC Director Dr. Mandy Cohen is here to talk about that effort. Thanks for joining us. Thanks for having me, Ari. The CDC says the risk to humans from the H5N1 flu that is driving this outbreak is low. Right now, it appears that the two cases in humans were from contact with sick animals. Do you have any reason to believe that humans could pass this on to each other? So we have never seen a case of human-to-human

spread of avian flu here in the United States. And the version of avian flu that we're seeing in cattle and in this one human case is the same strain that we have seen previously in birds. We've never seen that spread human-to-human. That all being said is we've learned through COVID and our experiences, viruses change, and we need to stay ahead of it. That's why we and CDC and the whole of U.S. government is taking this very seriously and monitoring the situation very closely. You say we need to stay ahead of it. Tell us what that involves. What are the steps you're taking? Sure. One is obviously working very closely to make sure we're understanding the extent of the spread, how many cattle and farm are involved, and then obviously looking for any humans that are in contact with cattle or sick birds and testing folks that have symptoms and

making sure that we're understanding if it has spread to other folks. So far, there's only been one case in Texas. The person had very mild symptoms. They're recovering well, but we want to make sure, again, that we are testing folks who may have been in contact. Just so people understand the difference in numbers, there's one case in Texas where the farm worker appeared to have been in contact with a sick cow. A couple years ago, there was another human case where the person appeared to have been in contact with a sick bird. You said widespread testing is important. Is there a risk that cases are going to go under the radar because people are afraid to report, whether it's farm owners who don't want their operation to be shut down or farm workers who might not have health coverage? Well, we're working closely with our state and local partners, our partners through

agriculture and the U.S. Department of Agriculture and farm workers. Again, we want to get ahead of this. So we're trying to talk folks through it and build trust. And, you know, folks have really been receptive. We've been particularly working with a lot of the veterinarians that are part of the farms that have been impacted. So, so far, all working well together. Cows were not thought to be a species at high risk. And so if the virus is now spreading in cows, what are the chances that it could mutate to become a risk to humans? Well, it is true. spreading in cows, what are the chances that it could mutate to become a risk to humans? Well, it is true. This is the first time we've seen avian flu or bird flu in cattle. And as you know, cows are mammals. So this is a new group of animals that we are seeing this virus in.

And that just means more opportunity for this virus to mutate and change. And that's what we want to make sure we are continuing to stay ahead of. Monitoring whether it continues to spread and evolve is one thing. Preparing for the possibility that it might is another. In a New York Times opinion piece, columnist Zeynep Tufekci said, the government needs to gear up to potentially mass-produce vaccines quickly. Do you agree with that? Well, the good news is the United States has been preparing for avian flu outbreaks for more than 20 years. We've invested in our ability to test for this,

to prevent it, and to treat it. And we know that the strain we're seeing right now is the same strain we have seen before. Tests will pick this up. Our treatment, which is Tamiflu, which we have both doses in stockpile and around the country works. And we even have vaccine candidates that are ready to go. So it's very different than what we experienced, for example, at the beginning of COVID, when we're seeing a brand new novel virus where we didn't have tests, we didn't have treatment, and we didn't have vaccine. But just specifically, if it does take time to mass produce vaccines, is that something the U.S. should be doing in earnest right now on the chance that the virus evolves? Well, again, we have never seen a transmission from a human to human. That is something we are watching for very closely. And so there may

be trigger points where we would move to thinking about scaling up vaccine. But remember, there's always a tradeoff there. If we move to manufacturing one type of vaccine, it may be at the expense of being able to manufacture that vaccine for the seasonal flu. Again, something that also impacts us. So we have the ability to scale up if we need to. And again, we're already started down that process and we'll keep monitoring to see if we need to trigger and do that. The cases so far have all been in dairy cows. Should people be concerned about consuming milk and other dairy products? Well, first, FDA has indicated that our milk supply is safe because of the pasteurization process. Unpasteurized and raw milk remains a risk, but the vast, vast, vast majority of our milk supply is safe because of pasteurization. Dr. Mandy Cohen directs the Centers for Disease Control and Prevention.

Thank you for talking with us. Thanks, Ari. This episode was produced by Megan Lim, Janaki Mehta, and Erica Ryan with audio engineering by Stu Rushfield. It featured reporting by Joe Hernandez and Will Stone. It was edited by Jeanette Woods and Patrick Jaron-Watanana. Our executive producer is Sammy Yenigan. It's Consider This from NPR. I'm Ari Shapiro.