In experiments, mice get ill from raw milk carrying bird flu virus

Confirming the risks of consuming uncooked cow’s milk when the H5N1 avian flu virus is circulating in U.S. dairy herds, researchers discovered that mice fed the milk shortly bought unwell.

“Our information point out that HPAI A[H5N1] virus in untreated milk can infect vulnerable animals that eat it,” concluded a staff led by virologist Yoshihiro Kawaoka, of the College of Wisconsin–Madison. His staff printed the findings Friday within the New England Journal of Medication.

In late March, researchers first detected traces of H5N1 hen flu in nasal swabs and milk obtained from U.S. dairy cows. Since then, the outbreak has been detected in lots of dairy herds throughout a number of states.

To date, H5N1 doesn’t appear to transmit simply between animals and people: There have been solely two recognized human instances of H5N1 an infection linked to the U.S. dairy cow outbreak. Each have occurred in dairy staff who’ve had prolonged, shut contact with the animals.

Specialists additionally consider the final milk provide to be secure, because the heating concerned in pasteurization kills the virus.

Nevertheless, consuming unpasteurized “uncooked” milk—a craze amongst a small subset of customers—could, in reality, run the chance of passing H5N1 to different mammals, together with folks.

To search out out if that’s true, Kawaoka and his staff gave mice uncooked cow’s milk recognized to be contaminated with the H5N1 virus. The rodents acquired the milk by mouth.

The mice confirmed typical indicators of an infection, reminiscent of “ruffled fur and lethargy” as quickly as in the future after being fed the milk, the researchers reported.

“All of the animals survived till day 4, once they had been euthanized to find out virus titers [levels] in a number of organs,” Kawaoka’s group mentioned.

“We detected excessive virus titers within the respiratory organs [which suggests that infection may have occurred through the pharynx] and reasonable virus titers in a number of different organs, findings in step with the systemic infections usually brought on by HPAI H5 viruses in mammals,” the staff reported.

Excessive ranges of virus had been additionally discovered within the feminine mice’s mammary glands, although they weren’t lactating, the researchers mentioned.

Primarily based on their findings, the researchers consider that mammalian an infection with the avian flu virus can occur after consuming cow’s milk containing the pathogen if the milk has not been heat-treated, as occurs with pasteurization.

Individuals who drink uncooked milk could consider that refrigeration can kill off the H5N1 virus. The researchers investigated that notion, refrigerating the contaminated milk at a temperature of 39 levels Fahrenheit.

Nevertheless, ranges of virus within the unpasteurized milk declined solely slowly whereas stored at this temperature for 5 weeks, suggesting that the “virus could due to this fact stay infectious for a number of weeks” beneath these circumstances, in keeping with the researchers.

As for pasteurization, the scientists put uncooked, contaminated milk by means of heating processes much like these used within the pasteurization course of. They report that ranges of virus had been diminished to undetectable or barely detectable ranges, however in some instances not utterly eradicated.

Kawaoka’s staff burdened that “the circumstances utilized in our laboratory research will not be an identical to the large-scale industrial [pasteurization] therapy of uncooked milk.”

Nonetheless, the analysis appears to substantiate that the true hazard of passing H5N1 onto customers lies within the consumption of uncooked milk.

“Do not drink uncooked milk—that is the message,” Kawaoka advised the New York Occasions.

And there are extra causes than hen flu to keep away from uncooked milk.

Based on one 2022 study from the U.S. Facilities for Illness Management and Prevention, uncooked milk consumption has been linked to 228 hospitalizations, three deaths and sickness in additional than 2,600 folks between 1998 and 2018.

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