More than half of cats died after drinking raw milk from bird flu-infected cows

More than half of the cats around the first Texas dairy farm to test positive for bird flu this spring died after drinking raw milk from infected cows, scientists reported this week, providing a window into the harmful consequences of the virus during its unprecedented spread across the country. cattle industry.

The report, published Tuesday in the Centers for Disease Control and Prevention’s journal Emerging Infectious Diseases, chronicles the first investigations by veterinarians and university laboratories into an illness that began spread through cows across the region earlier this year.

Texas farm cats had been fed raw milk from cows found to be infected with highly pathogenic avian influenza, or HPAI H5N1. A day after the farm started noticing the cows getting sick, the cats started getting sick too. By the end, more than half of the cats were dead.

“The cats were found dead without any apparent signs of injury and belonged to a resident population of (approximately) 24 domestic cats fed milk from sick cows,” the scientists wrote.

Tests of samples taken from the brains and lungs of dead cats returned results suggesting “large quantities of virus.” Autopsies of the cats also revealed “microscopic lesions consistent with a serious systemic viral infection,” they said, particularly in the eyes and brain.

About 1 in 5 milk samples checked by the Food and Drug Administration from U.S. retailers tested positive for H5N1, although the agency said last week that studies so far show that pasteurization works to kill the virus in milk; only harmless fragments remained. Officials have repeatedly urged Americans do not drink raw milk.

Although the spread of the virus from cows to cats through raw milk is new, cats have long been known by scientists as one of the species particularly vulnerable to serious illness from H5N1.

The U.S. Department of Agriculture said deaths and neurological illnesses in cats had been “widely reported” on farms where the virus was present.

In contrast, only a fraction of cows – up to 15% – developed signs of disease in infected herds, the scientists said. Officials said cows largely recovered within a month of their infection. The virus has been devastating for flocks of poultry who faced numerous deaths or had to be put down after contracting the virus from wild birds.

Previous research has linked deaths and neurological disorders in domestic cats to infections with the H5N1 virus. An earlier study published by the Thai journal CDC in 2006 suspected that a cat contracted the virus after eating an infected pigeon.

But recent infections prompted the CDC to issue new guidance this month for veterinarians treating suspected cases of H5N1 in cats, calling for enhanced measures, such as wearing respirators and protective eyewear, to avoid contracting the virus.

“Although it is unlikely that people will become infected with the avian influenza virus through contact with an infected wild, stray, feral or domestic cat, it is possible, especially if there is prolonged, unprotected exposure to the animal,” the agency said in its report. advice.

Some human cases have also been suspected of being caused by eating infected birds, such as in Cambodia earlier this year.

Meanwhile, authorities have scrambled to curb the spread of the virus among dairy cattle, which is believed to have spread from cow to cow since first contamination by wild birds earlier this year.

“Ingestion of food contaminated with feces from wild birds infected with HPAI virus is presumed to be the most likely initial source of infection on dairy farms,” the scientists wrote.

The U.S. Department of Agriculture announced Monday that it will test ground beef sold at retailers for the H5N1 virus and study how cooking beef could reduce the potential risk posed by the virus, following the epidemic. an earlier order intensifying testing on dairy cattle shipped across state lines.

It is unclear whether samples of ground beef have tested positive for the virus so far. The results “are forthcoming” and will be shared as soon as they are available, the spokesperson said.

Meanwhile, more than 2,000 tests have been carried out by the department so far this month on cattle.

“As of April 30, 34 dairy herds have been affected by the H5N1 virus. For context, there are more than 26,000 dairy herds across the country,” the spokesperson said in a statement.