Dr. Marcus Pereira: We have to prepare for the worst and hope for the best. That’s the way to go here. And people have to have their antennas up. The authorities have to be doing their work in monitoring this, so that we are ready to go when this thing jumps to humans.

Courtney: Welcome to Health Matters, your weekly dose of the latest in health and wellness from NewYork-Presbyterian. I’m Courtney Allison.

With bird flu in the news, you might be wondering, “should I be worried?” This week, we’re joined by Dr. Marcus Pereira, an expert in infectious disease from NewYork-Presbyterian and Columbia, to help answer your questions about bird flu.

Dr. Pereira explains how the virus can spread from an animal to a human, the symptoms, and if it’s safe to eat eggs, meat, and dairy products.

Courtney: Hi, Dr. Pereira. Thank you so much for joining us today.

Dr. Marcus Pereira: Oh, I’m so glad to be here. Thank you for the invitation.

Courtney: So we’re here to talk today about bird flu, which has been circulating in the news quite a bit lately. Can you tell us: What is bird flu? And how concerned should the general public be?

Dr. Marcus Pereira: Sure. Well, we can start with what is bird flu.

So, as many of you know, there’s multiple different types of influenza virus, right? So there’s the seasonal influenza, usually both a mixture of influenza A and B viruses, and those have been circulating among humans for decades. And that’s what the vaccine is designed to protect us from and every year they change slightly and that’s why we get the vaccine updated each year.

So that’s the background of influenza that’s always normal for humans to be exposed to. Now, bird flu, what everybody’s hearing in the news, is an emerging pathogen that may be of potential risk to humans. From what we know of it, it was first identified in 1996 in China, and the exact denomination is influenza A H5N1.

And each influenza virus has its own designation. So the current human influenza viruses are usually like H3N2 and something like that. But this happened to be H5N1. There’s nothing special about that particular designation other than it’s unique to this particular type of virus that originated in birds and has been circulating for a few decades now among local bird populations.

But the issue has been that since last year, it took off and started infecting multiple different populations. First, of wild birds around the globe. And then it made the transition to other mammals. But then in 2024, we first detected in cows and among chickens in poultry farms. And that, sort of, raised all sorts of alarms because these are populations that humans get exposed to.

And there’s obviously a lot of poultry farms and cattle farms that have a lot of these animals and they have been extensively impacted by this particular bird flu virus.

Courtney: I read that it’s also concerning that it’s spread to cattle because their respiratory systems are similar to humans. Can you explain why that’s significant?

Dr. Marcus Pereira: So we are much closer physiologically to cows and pigs and sea mammals like seals and otters and so forth. So that, then the jump from mammals to humans, it’s much easier for the virus to accomplish than from birds or other types of, like, non-mammal animals to get to humans. And that’s the concern. It’s getting close enough to us anatomically and physiologically.

That could then potentially start infecting humans and then make the definitive and most concerning transition of human to human transition, right? Like, it’s just a matter of experimentation and time for the virus to then, to be able to infect from human to humans.

Courtney: So I was going to ask how it spreads to humans. It sounds like right now contact with animals?

Dr. Marcus Pereira: That’s exactly right. So intense contact with infected animals. Because some of these animals don’t appear to be sick. So the cases of humans who have developed bird flu so far, they generally have been a very mild set of symptoms, including things like a mild cough, mild fatigue, low grade fevers, and very interestingly, also conjunctivitis, which is the medical term for pink eye. So in cows, studies have shown that the milk is full of influenza virus.

So dairy workers, they’re at high risk. And if you’re cleaning the chicken coop, for example, you know, you may get yourself inoculated with the bird flu virus. The way that, sort of, dairy workers were infected was through milking the cows. And there’s a lot of, sort of, aerosolized milk that gets in the air or the dairy farm workers got their hands full of milk and then were, you know, scratching their eyes or touching their eyes and then transmitted the virus directly onto their eyes and then hence the pink eye.

Courtney: What can we do to protect ourselves? I guess first on the farm worker level, if you’re coming into contact with potentially infected animals and just a regular member of the public.

Dr. Marcus Pereira: If a farm is known to have some bird flu, the farm workers absolutely need to be wearing protective equipment: mask, gloves, gowns, and even goggles, right?

So I cannot even imagine how difficult it would be for a worker at this time. And then for the general population, what can people do to protect themselves? One, if you come across animals, right, whether these are dead birds in your backyard, don’t touch them. And there’s pretty good guidance in the CDC website and other websites about what to do if you find a dead animal in your backyard.

Certainly wearing gloves, wearing masks, and being very careful about disposing of that, like triple bagging, for example. Some counties, for example, they urge the person to contact the Department of Health or the Department of Environmental Services. Additionally, I think that it’s a great opportunity to emphasize that everybody should get the influenza vaccine if they have not obtained that so far.

It’s still an important, sort of, element to protect yourself. And the idea there is not that the current human influenza vaccine is going to protect you against bird flu, but the last thing we want is for humans to be infected with both the regular human influenza and then the bird flu. Because if a human has both viruses, that’s how the virus is going to acquire the ability to infect humans and cause human to human transmission, right? And then now we’re in a pandemic situation.

Courtney: Say a human catches bird flu, is this worse than the flu that we’re more used to that transmits around humans? Or is it the mutations make it more dangerous? Or…

Dr. Marcus Pereira: Well, most of the cases that we’ve seen so far of humans acquiring bird flu have been very mild. Again, it’s pinkeye and maybe some mild cold-like symptoms. And they, most people have recovered. We’ve only had one documented fatality.

That was that older gentleman in Louisiana and a couple of severe cases. Everything else has been pretty mild and that’s maybe the silver lining here. But, you know, there’s no guarantee that once it jumps to humans and then it has widespread human to human transmission, if that happens, there’s no guarantee that it will be mild.

And because we do have historical knowledge, right? Think about the 1918 influenza pandemic, which really killed millions of people. That was, in some ways, similar to what’s happening right now. It was in sort of an animal reservoir. It jumped to humans who had no widespread immunity to that virus and really caused, you know, obviously devastating impact.

Courtney: Yeah.

Dr. Marcus Pereira: So that’s what we’re worried about, you know, and we don’t really know, is it going to be something like that or maybe a milder pandemic? I think it’s difficult to know ahead of time.

Courtney: How contagious is bird flu?

Dr. Marcus Pereira: Well, between animals, for the animals that it’s established a foothold, it’s been very contagious, right?

So you have these reports of populations of wild birds being decimated within a week or so, including also mammals, for example, in Patagonia of sea lions being wiped out. So once it achieves that transmission within a species, it can really spread like wildfire. Like once it reaches a dairy farm, all the cows are infected. Same with chickens. It’s spreading very rapidly.

Courtney: So how might a doctor diagnose bird flu?

Dr. Marcus Pereira: Great question. So someone coming in, clearly with flu-like symptoms, you do a battery of tests and you don’t identify the usual viruses, including no influenza. So that might be a situation where you might think of, should I contact my local health department and see if this person should be tested for it?

And obviously the more particular risk factor is: were they exposed to any kind of animal, whether sick or not, at this point, right? That could have been a mode of transmission for that. So I think that we’re all being taught to ask, were you around any animals, sick or not? Whether these are birds, cattle, other mammals, if someone clearly has flu-like symptoms, but the general tests for the regular human influenza is negative, that might be a reason to test.

There’s also some effort into looking at wastewater testing, that you can detect whether bird flu virus is circulating in that community. So wastewater, right? It contains a number of different pathogens and people started using that as a way to detect what kind of viruses are circulating in a particular community.

That kind of monitoring took off during COVID. And, you know, initially they were just seeing like, could this correlate with a major outbreak? And it does actually, sort of. Wastewater levels of, for example, SARS-CoV-2 went up when there was a major outbreak in that particular area. And if you go to the CDC website, actually, there are some data about wastewater surveillance for bird flu.

The idea is that then the health department can alert hospitals to say, “Hey, we’re seeing an uptick in wastewater bird flu. You might want to consider testing your patients or considering bird flu in your patients more regularly.”

Courtney: And so if a person does contract bird flu, what are the recommended treatments?

Dr. Marcus Pereira: It looks like our currently available anti influenza therapies, like Tamiflu, for example, seem to be active against bird flu. And that’s what has been used for farm workers who have been exposed. And they had mild symptoms to begin with, but it looks like there was some symptom relief with the use of Tamiflu, also known as oseltamivir, right? That’s the generic term for that antiviral. Other anti influenza medications like baloxavir and zanamivir are also active against bird flu.

Courtney: Does the U. S. have a vaccine against bird flu yet?

Dr. Marcus Pereira: There are studies for an mRNA vaccine, but you can’t get it right now. You can’t go to your doctor and ask for the bird flu vaccine. It’s not available yet.

Courtney: Right. So yeah, it’s not at the local drug store.

Dr. Marcus Pereira: No, unfortunately not.

Courtney: So I’d love to talk about what’s on a lot of people’s minds, which I think is, impacts to the food supply. I think there’s a lot of concern about bird flu possibly being in eggs.

Dr. Marcus Pereira: Yeah.

Courtney: So let’s start there. Do you think it’s safe to eat eggs?

Dr. Marcus Pereira: It is safe to eat eggs, but they have to be cooked, so the virus can be killed off by heat. Right? So raw eggs should not be consumed by anyone. Raw milk or unpasteurized milk should also not be consumed by anyone. We know that there’s plenty of bird flu virus among infected cows and it gets into the milk.

But the pasteurization process, which is heating up the milk that kills off all the germs, you know, that’s a tried and true technique that has been used now for over a hundred years. So that makes the milk supply safe. When it comes to eggs, you just have to cook them and that should eliminate the threat of the virus.

Courtney: Is there anything else we should be avoiding? I mean, is it safe to eat chicken, beef?

Dr. Marcus Pereira: Yes, as of now, it is safe to consume all of those things, provided that they are cooked. And, you know, this is not a time to experiment with, like, raw chicken, raw beef, raw eggs. I mean, you’re just putting yourself at risk.

As long as things are properly cooked, studies have shown, you know, that you can kill off the virus, and hence making it safe for you to consume it.

Courtney: So today, what are you kind of watching out for in the news and following the studies with all this?

Dr. Marcus Pereira: Yeah, just because it may transmit from human to human, it may or may not be severe, or it may be severe in certain populations like immunocompromised individuals or those with preexisting lung conditions, right?

Like, you know, COPD or asthma, for example, and in others who are generally healthy might be okay, or the reverse, actually. And this is what, unfortunately, we experienced with the 1918 pandemic. That flu strain infected children and those at healthy age more so than the elderly. And that was obviously very devastating.

So anyways, the type of clinical scenarios, whether it’s mild, severe, and who’s getting sick from it, will be very important to know. For example, the 2009 swine flu pandemic, if you remember, there was an enormous alarm and anxiety about that. It turned out that that virus was a reassortment between birds and pigs that made their way to humans.

It wasn’t that severe. People had mild symptoms. They came through, people got it. And there were no major consequences of that, right? So that was obviously a lucky break that we had. And maybe we’ll have another lucky break with this, but we can’t bet on it, right?

We have to prepare for the worst and hope for the best.That’s the way to go here. And so people have to have their antennas up. The authorities have to be doing their work and monitoring this, understanding what is happening, and preparing us with treatments and vaccines so that we are ready to go when this thing jumps to humans.

Courtney: Dr. Pereira, thank you so much for your expertise and for such a wonderful conversation on a topic that’s on a lot of people’s minds.

Dr. Marcus Pereira: Well, pleasure is all mine. Thank you so much.

Courtney: Our many thanks to Dr. Marcus Pereira. I’m Courtney Allison.

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