Bird Flu in Beef Begins to Worry Some Scientistists. Heres Why. – Barron’s

The discovery of bird flu virus particles in the muscles of a dead dairy cow last month came as a shock to Dr. Carol Cardona, a bird flu scientist and a professor at the the University of Minnesotas College of Veterinary Medicine.

It was an eye-opener for me, Dr. Cardona said.

Most reports about the H5N1 virus, the strain of avian flu that appeared in U.S. cattle earlier this year, have described relatively benign symptoms in affected dairy cows: Drops in milk production, dehydration, and fever. To Cardona, those symptoms suggested that the virus spread was minimal within each infected cow.

The number of organs infected, affected, etc., that is directly correlated with the amount of clinical signs you see in an animal, Cardona says. Thats why I was assuming this was restricted to certain parts of the body.

The fact that the U.S. Department of Agriculture had found viral particles in muscle tissue of this one dairy cow, however, toppled that assumption.

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The discovery opens up new routes of transmission of the virus, both to humans and to animals of other species that might come into contact with beef.

The USDA says the beef supply remains safe and the finding doesnt mean a broader outbreak is imminent. But Cardona says its a moment to readjust our expectations around what might be possible with the outbreak.

The failure to stop big events is not the failure to be able to stuff the genie back in the bottle, Cardona says. Its the failure to imagine what could be true.

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To me, its a significant deal, Cardona says. They found this animal, they tested it, thank goodness, and it didnt enter the food chain. Thats a great thing. But that was luck. Now, you have to go through and say, would we have missed any of these?

The Centers for Disease Control and Prevention continues to say that the current public health risk is low. There have only been three identified cases of infection in humans since the dairy cow outbreak was discovered in March, despite the widespread presence of the virus on dairy farms and in unpasteurized milk.

And, so far, the highly sensitive PCR tests that the USDA uses to search for H5N1 in beef has only found viral particles in the muscle of one of 109 dairy cows tested. All of those cows had been pulled by USDA inspectors from the food supply at slaughterhouses because they appeared sick.

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The report on the viral particles found in the dead dairy cows muscle last month has drawn split reactions from food safety experts and virologists. Food safety experts, in particular, dont seem concerned by the latest finding.

You would expect to find some particles of virus in some of those samples, and the fact that weve theyve only found one cow that they even detected particles so far is actually pretty amazing, said Keith Belk, head of the Center for Meat Safety and Quality at Colorado State University.

So far, H5N1 is only known to be present in dairy herds, not in the cattle herds raised solely for beef. Belk said that he is confident that inspectors with the USDAs Food Safety and Inspection Service (FSIS), who are based at commercial slaughterhouses, will catch all the infected dairy cows before they enter the food supply.

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Of the roughly 2.5 million cattle slaughtered at federally inspected plans in the U.S. each month, around 10% are dairy cattle. Dairy cows, Belk says, are generally sent to specialized slaughterhouses, where the volume is lower and the oversight by federal inspectors is more stringent.

Any cow that has symptoms of being infected with the virus is going to be detected, and then subsequently tested, Belk said.

The USDA, in a statement, said it was confident in its inspection process. The cow that tested positive was identified as having signs of illness by FSIS personnel, providing further confidence that the food safety system we have in place is working, a spokesperson said.

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But bird flu scientists had a different take. It is not reasonable to assume that FSIS inspectors will identify and condemn all H5N1 infected cows, said Jrgen Richt, director of the Center of Excellence for Emerging and Zoonotic Animal Diseases and a professor at the Kansas State University College of Veterinary Medicine. For me, this is concerning.

Milk is pasteurized before its sent to consumers, Richt wrote in an email to Barrons. Beef is not.

Cardona, who is trained both as a veterinarian and a scientist, says that she will continue to eat beef, because proper cooking will kill the virus. But she said she was concerned about other animals contracting the virus from beef.

According to a CDC report, half of a group of 24 cats fed milk from sick cows on one dairy farm got sick and died.

The pathways are there, Cardona says. We really have to wake up and start paying attention, because the mitigation strategies are there, too.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com

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Bird Flu in Beef Begins to Worry Some Scientistists. Heres Why. - Barron's