A Michigan dairy worker has been diagnosed with bird flu, marking the second human case associated with the ongoing outbreak in U.S. dairy cows.
The male worker, who had been in contact with infected cows at a farm, experienced mild eye symptoms but has since recovered, according to U.S. and Michigan health officials.
Although a nasal swab from the worker tested negative for the virus, an eye swab taken on Tuesday came back positive, indicating an eye infection. The worker developed a “gritty feeling” in his eye earlier this month, but Dr. Natasha Bagdasarian, Michigan’s chief medical executive, described it as a “very mild case.” The worker did not receive treatment with oseltamivir, a medication recommended for treating bird flu.
Health officials emphasize that the risk to the public remains low, but farmworkers exposed to infected animals are at higher risk and should be provided with protective equipment, especially for their eyes. An investigation is ongoing to determine whether the Michigan farmworker was wearing protective eyewear at the time of exposure.
This case follows the first known instance globally of a person catching this version of bird flu from a mammal, which occurred in late March when a farmworker in Texas was diagnosed with eye inflammation and subsequently recovered.
Since 2020, a bird flu virus has been spreading among various animal species, including dogs, cats, skunks, bears, seals, and porpoises, in numerous countries. The detection of the virus in U.S. livestock earlier this year raised concerns about food safety and the possibility of human-to-human transmission.
As of Wednesday, the virus had been confirmed in 51 dairy herds across nine states, with 15 of those herds located in Michigan. The CDC’s Dr. Nirav Shah stated that the case was “not unexpected” and that more infections could be diagnosed in people who work around infected cows. U.S. officials have tested 40 people since the first cow cases were discovered, with Michigan testing 35 of them.
Despite the concerns, there is currently no indication that the virus is causing flu-like illness or spreading among people. Epidemiologist Michael Osterholm noted that if several people were seriously ill with respiratory illness, it would have been detected by now.
While the virus has been found in high levels in the raw milk of infected cows, government officials assure that pasteurized products sold in grocery stores are safe, as heat treatment has been confirmed to kill the virus.
This latest case marks the third time a person in the United States has been diagnosed with the Type A H5N1 virus, following a prison inmate in Colorado who contracted the virus while killing infected birds at a poultry farm in 2022, prior to the virus’s appearance in cows.
The Associated Press contributed to this article.