U.S. orders cows tested for avian influenza after food milk tests positive

The Department of Agriculture has ordered the dairy industry to test dairy cows for highly pathogenic infections. Avian influenzaor before HPAI H5N1 travels between states, federal officials announced Wednesday.

USDA’s move to tighten testing requirements for HPAI H5N1 comes after the Food and Drug Administration disclosed On Tuesday, it was announced that a sample of pasteurized milk sold on grocery store shelves had tested positive for the virus, making it clear whether the positive test was caused by lingering dead “viral particles” or live infection. This prompted further research to determine whether it was caused by a sexually transmitted virus.

The announcement also comes after federal authorities said they had discovered an “isolated” but alarming change in the virus in cattle, which U.S. officials believe was contracted from wild birds. .

State veterinarians and laboratories that test positive for the virus in cattle will be required to report the results to the Department of Agriculture. Farms with sick cattle must be inspected before moving cattle across state lines.

“The main focus is order, initially it will be a lactating cow. But there is certainly an opportunity to expand beyond that if needed,” Mike Watson, director of the USDA's Animal and Plant Health Inspection Service, told reporters Wednesday.

official said before Based on analysis of genetic sequences collected from sick cows, researchers found that the unprecedented spread of the virus among dairy cows was likely traced back to a single spillover event from wild birds.

Since then, genetic data and research suggests the virus is spreading to infect cattle around the world. at least 8 states and human dairy worker In Texas. Making matters worse, egg farms in Texas and Michigan are also suspected of having contracted the virus, which spreads from cows. millions of poultry They are culled due to infection from wild birds.

“These farms were in close proximity to the affected dairy farms, so there could be lateral flow from the dairy farms to these poultry operations and then to these egg-laying operations. It could be transmission of the virus through fomites such as “on clothing or vehicles,'' said Jamie Jonker, chief scientific officer at the National Milk Producers Federation. This was stated in a Health Information Center webinar.

Officials said the virus was initially undetectable in the respiratory tract of most infected cows, suggesting it was not transmitted through the air between cows like other types of influenza. Instead, his H5N1 HPAI in the current epidemic has been found almost exclusively. in raw milk And the cow organs that produce it. Officials believe the virus may have spread between cows during the milking process on the farm, via surfaces contaminated with infected raw milk.

However, Watson said signs of the virus were found in the lung tissue of at least one cow headed for slaughter. Watson said the cow was condemned by USDA inspectors and was not added to the food supply.

Federal scientists also discovered a mutation in another sick cow in Kansas that carries a genetic change that makes influenza easier to spread to mammals.

“This one sequence change and one dairy cow with H5N1 in its lung tissue appear to be isolated events so far, but new transfers of H5N1 between wild birds and dairy cows are likely to lead to further Testing is required,” Watson said.

Most of the cows have recovered from the virus without dying, Watson said.That's in stark contrast to something like mass death seen in birds etc. other species. However, dairy industry officials have previously said that some cows have not yet regained their ability to produce milk, raising concerns that some may have long-term problems.

“We need time to develop a better understanding to support future courses of action, so this federal order is critical to increasing the information available to USDA,” Watson said.

H5N1 HPAI virus detected in pasteurized milk

Health officials say previous studies that have pasteurized eggs for the HPAI H5N1 virus and milk for other bacteria have shown that this process is sufficient to eradicate the danger from residual traces of the virus in milk. He said he thinks this suggests that the product is pasteurized, but says research is currently underway to verify that it has been pasteurized. Milk remains safe.

“A positive PCR test does not necessarily mean that the sample contains an intact infectious agent, but rather whether the intact pathogen is still present or infectious “Additional testing is needed to determine whether any remains.” At a press conference.

This includes what the FDA has said is the “gold standard” for determining whether the virus it has discovered can be transmitted, by collecting the H5N1 HPAI particles it has discovered and making sure they are Check to see if it grows in chicken eggs.

Research supported by the National Institutes of Health also detected H5N1 HPAI fragments in milk. Initial testing of these samples suggested that the virus in the pasteurized milk was not infectious and was trying to reproduce in cells and chicken eggs.

“While this is welcome news, this effort studied a small number of samples that are not necessarily representative of all retail milk. So to really understand the scope here, we will wait for the FDA. “There is a need for this,” the National Institute of Allergy and Infectious Diseases said. Directed by Dr. Jeanne Marazzo.

Prater said the samples were obtained from a national survey of the U.S. milk supply, but did not provide details about where the samples were found or what type of milk tested positive.

“We don't have any information to share yet, but it will be announced soon and that's all we can share at this time,” Prater said.

Prater said milk from cows known to have symptoms of the virus has not entered the supply chain. However, Professor Prater said the virus could enter the supply chain from other sources, perhaps from cattle that have not yet shown symptoms or have previously recovered.

Prater said the FDA has some data that could help law enforcement trace where the virus-laden milk entered the food supply.

“At this point, we will be able to review the information we are collecting as part of this. Our traceability information is good, but not perfect,” Prater said.