A type of avian influenza that has been extremely deadly in birds has been confirmed in U.S. dairy cattle in Texas and Kansas, the Division of Agriculture introduced on Monday.

It’s the first time that cows contaminated with the virus have been recognized.

The cows seem to have been contaminated by wild birds, and lifeless birds have been reported on some farms, the company mentioned. The outcomes have been introduced after a number of federal and state companies started investigating stories of sick cows in Texas, Kansas and New Mexico.

The sickness has primarily affected older cows, inflicting signs that embody diminished urge for food, fever and a sudden drop in milk manufacturing. Up to now, the united statesD.A. mentioned, there had been few or no stories of deaths within the affected herds.

In a number of circumstances, the virus was detected in unpasteurized samples of milk collected from sick cows. Pasteurization ought to inactivate the flu virus, specialists mentioned, and officers harassed that the milk provide was protected.

“At this stage, there isn’t any concern in regards to the security of the industrial milk provide or that this circumstance poses a threat to client well being,” the company mentioned in a press release.

Exterior specialists agreed. “It has solely been present in milk that’s grossly irregular,” mentioned Dr. Jim Lowe, a veterinarian and influenza researcher on the School of Veterinary Medication on the College of Illinois at Urbana-Champaign.

In these circumstances, the milk was described as thick and syrupy, he mentioned, and was discarded. The company mentioned that dairies are required to divert or destroy milk from sick animals.

The cattle infections come on the heels of the nation’s first detection of extremely pathogenic fowl flu in goats, which was introduced by Minnesota officers final week.

Up to now, the flu samples from sick cows haven’t contained genetic mutations which are identified to make the virus extra prone to infect people, the agriculture company mentioned, including that the danger to most of the people remained low.

“There’s nonetheless no trigger to panic,” mentioned Stacey L. Schultz-Cherry, a virologist and influenza knowledgeable at St. Jude Youngsters’s Analysis Hospital. “It simply seems prefer it’s one other spillover occasion as a result of contact with diseased wild birds.”

Nonetheless, she famous, cows weren’t considered among the many species that have been significantly prone to avian influenza, and the circumstances have been one other worrisome flip in a world fowl flu outbreak that has devastated wild fowl populations over the previous few years.

The outbreak has been brought on by a brand new type of fowl flu virus, referred to as H5N1, that emerged in Europe in 2020. Wild birds can unfold the virus, by their feces and oral secretions, to farmed poultry and different animals. Outbreaks usually flare up within the spring and summer time, when migrating birds are on the transfer.

Though avian influenza viruses are tailored to unfold primarily amongst birds, the brand new model of H5N1 has grow to be so widespread in wild birds that it has additionally repeatedly unfold to mammals, particularly scavenging species, corresponding to foxes, that may feed on contaminated birds.

Infections of mammals, which give the virus new alternatives to evolve, are all the time a supply of some concern, Andrew Bowman, a molecular epidemiologist and influenza knowledgeable at Ohio State College, mentioned. Scientists have lengthy been involved {that a} fowl flu virus that developed to unfold extra effectively amongst mammals, together with people, might set off the following pandemic.

At this level, Dr. Bowman mentioned, it stays unclear whether or not the contaminated cows have all picked up the virus immediately from birds or whether or not the virus can also be spreading from cow to cow.

“That’s a query that’s going to need to get resolved shortly,” he mentioned. “If we’ve transmission cattle to cattle, that’s a unique story. That definitely makes me a little bit extra nervous.”

Further testing and evaluation are underway. “This can be a quickly evolving state of affairs, and U.S.D.A. and federal and state companions will proceed to share extra updates as quickly as info turns into accessible,” the company mentioned.