Experts believe three more cats in Los Angeles County are infected with the H5N1 bird flu. Two others succumbed to the illness earlier this month after drinking recalled raw milk from Fresno-based Raw Farm LLC dairies.

Of the three newly ill cats, two died and one tested positive for influenza A, an unusual finding in domestic cats that had not been exposed to infected birds or contaminated dairy products. The two deceased could not be tested during their lifetime, but experts believe that their deaths were probably due to the H5N1 virus.

The three cats all lived in the same household.

Influenza A viruses include most seasonal human flu viruses and H5N1. Health authorities are not yet sure where the cats became infected with H5N1 – although they indicated in a statement that they are investigating raw meat as a source and are awaiting test results.

“The risk of H5 avian influenza remains low in Los Angeles County, but these confirmed cases of the virus in domestic cats serve as a reminder that consumption of raw dairy and meat products can cause serious illness in cats,” said Barbara Ferrer, Director of the Los Angeles County Department of Public Health, in a statement.

She urged county residents to “avoid raw dairy products and undercooked meat products, limit contact with sick or dead animals, report sick or dead birds, and keep pets or poultry away from wild animals and birds.”

The final three cats all had respiratory illnesses and had no known exposure to raw milk; Investigators are checking whether the animals ate raw meat.

According to health authorities, the cats lived exclusively indoors.

People who had direct contact with the cats are being monitored for symptoms and given antiviral medication. According to the researchers, there have been cases of transmission of bird flu from cats to humans.

It’s unclear how many cats have died since H5N1 began circulating in dairy cows earlier this year. However, they are extremely susceptible to the virus, and dead barn cats are considered an early biological warning that a dairy is infested with the virus.

On a Texas dairy farm this spring, 12 barn cats died after drinking infected raw milk. Sykes also noted a 2023 outbreak in South Korea in which shelter cats ate pet food made from H5N1-infected raw duck. At one animal shelter, 38 of 40 cats died after eating the contaminated food.

Last year, the World Health Organization reported sporadic cat deaths in areas where H5N1 avian flu was circulating, including at one site in Poland where a group of 46 cats died; 29 of these animals were found to have tested positive for the avian influenza virus.

Larger cats, including captive lions, tigers and panthers, have also died as a result of eating meat contaminated with bird flu. This also applies to wild California bobcats and mountain lions.

Symptoms of H5N1 infection in cats include difficulty breathing, bloody diarrhea and neurological abnormalities – loss of motor control, seizures, depressed mental state, stiff body movements, blindness, circling, copious eye and nasal discharge and coma – with rapid worsening and in some leading to Death cases.