BThe third flu has been hitting a little too close to home lately. In its testing of the commercial supply of milk, the U.S. Food and Drug Administration (FDA) reported on April 25, that 20% of milk samples tested in the retail market contained “viral fragments” of H5N1 bird flu. Many believe this is an underestimate; experts at Ohio State University found that as much as 40% of milk samples from processing facilities in the Midwest may contain parts of the virus.
The results immediately raised concerns about the safety of the U.S. milk supply and the risk of infection for people who consume it. So far, the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization say the risk of people becoming infected from milk remains low. In the US, there have been only two known recent cases of H5N1 in humans: one in a poultry worker in 2022 and another in March in a person who worked with dairy cows.
The situation is changing rapidly. But here’s what we know now about the risks of bird flu to the milk supply.
Is milk safe to drink?
The FDA says its tests found fragments of the virus – which does not mean that viruses were alive and capable of infecting and causing disease. Agency scientists are carrying out additional tests to determine whether the fragments are still infectious, which would help them decide whether drinking affected milk could lead to infection. “First works of [National Institutes of Health]funded investigators indicate absence of infectious viruses in their studies of retail milk,” the FDA said. he said on your website. “To date, studies of retail milk have not shown results that would alter our assessment that the commercial supply of milk is safe.”
Milk on store shelves is pasteurized, which often kills viruses, and farmers have taken steps to discard milk from sick cows, the FDA says.
see more information: Is it safe to eat eggs and chicken during the bird flu outbreak?
Samuel Alcaine, associate professor of food science at Cornell University, is among the scientists studying the virus in cows to understand how much virus infected animals have, how sick they get, and how infectious those viruses can be if they pass into the milk or for milk. beef. (Cornell is part of the national network of laboratories that test milk samples from sick cows.) Alcaine says pasteurization is designed to kill heat-sensitive pathogens, and recent research on eggs has shown that the process inactivates H5N1. “We haven’t done full studies on milk; people are working on it now,” he says. “But I’m pretty confident that we’re going to see this heat-inactivated virus. Right now, I wouldn’t be at all worried about buying milk at the supermarket. I’m still doing it.”
What is the government doing to ensure milk is safe?
But even these measures may not be able to stop the spread of the virus, since it is unclear how many cows may be infected and asymptomatic (and therefore untested). So far, it appears that bird flu is milder in cows than in birds, in which it can be fatal. “We have heard reports of cows with virtually no signs of illness testing positive,” says Andrew Bowman, associate professor of preventive veterinary medicine at Ohio State University. (Bowman was the scientist who conducted his own test of retail milk and found that 40 percent of the samples contained viral fragments.) “It’s one of those things we’re going to have to understand; clinical signs to identify infected animals.”
Has H5N1 been found in beef?
Health officials are still investigating whether the virus is in beef, but Alcaine says so far it appears the virus is primarily found in cows’ mammary glands. “We’re still trying to understand how cow-to-cow transmission is happening,” he says. “But it is not actually eliminated in feces and it appears that viral loads are lower in the nasal cavity than in the mammary glands.” The same appears to be true of cow muscle. And it’s not clear whether both male and female cows can be infected, since most tests so far have been carried out on milk-producing females.
How widespread is bird flu in livestock?
As of April 26, the USDA confirmed 34 outbreaks of bird flu in cattle in nine states. However, testing is relatively scarce compared to the number of cattle in the U.S.
Why are health authorities concerned about the milk supply?
While the supply of milk is currently considered safe, things could change quickly, health experts say.
They’re watching how the virus moves from species to species and what genetic changes it picks up as it makes these jumps. Bird flu strains are generally not able to infect other species, including mammals. But the most recent case of bird flu in a person was also the first time the virus was found in cows.
The fact that it is now infecting cows – animals that people have closer contact with than other mammals that have harbored H5N1, such as foxes – means that the viruses could potentially be mutating that could spread and cause disease. in a significantly larger number of people.
Bowman says the FDA report is concerning because it suggests this specific strain of H5N1 continues to be transmitted between cows. “This is a rebound in a mammalian host that appears to be maintaining [the infection]”, he says. “In previous repercussions for mammals, they appeared to be mostly individual events that were isolated and did not continue to spread in these species. This is different.”
“Every time another animal or human is infected, it’s another game at the genetic roulette table in terms of whether the virus can transmit from human to human, which is what is needed for a pandemic,” says Michael Osterholm , director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “If you cast too many times, you may end up with a result you don’t want.”
see more information: Experts Can’t Agree on Whether We’re Still in a Pandemic
The biggest concern is if strains of bird flu start appearing in pigs. Pigs tend to be an effective vector for viruses of different species, which pigs transmit to people, as their cells share common characteristics with other animals and humans. If that happens, it’s more likely that a human-compatible version of bird flu could reach people.
On farms, this scenario would not be an exaggeration, as cows and pigs often coexist. The USDA issued dairy workers guidance increase efforts to clean milking equipment, spilled milk, clothing, vehicles and other animals that may come into contact with milk. The agency also warned that infected, unpasteurized milk could be a source of spread to other animals and potentially even people.
More testing is needed to determine whether there is any risk of the virus spreading through airborne particles expelled by infected animals. “The risk is not just respiratory from a breathing cow, but can be in the aerosols created in the milking process itself,” says Osterholm.
This is why the USDA also recommends that dairy workers wear personal protective equipment, such as masks and other body coverings, to limit their exposure to any viral particles.
For now at least, the danger to people remains low for the general public, Alcaine says. “O [infected] The cows are recovering and look like they will produce milk well again,” he says. Still, “it will take some time to understand how this is impacting the dairy cow population.”
This story originally appeared on Time.com read the full story
