Second US dairy worker infected with bird flu confirmed

Similar to the Texas case, the patient in Michigan only reported eye symptoms, the CDC said. The Michigan worker had mild symptoms and recovered, according to the state’s Department of Health and Human Services.

The worker had regular exposure to livestock infected with bird flu, Michigan said.

The CDC said “similar additional human cases could be identified” given high levels of the virus in raw milk from infected cows, and the extent of the spread in dairy cows.

Nirav Shah, CDC’s principal deputy director, said the agency received the Michigan patient sample on Tuesday and confirmed the positive test result that evening. The CDC said the investigation is just getting underway, and investigators are looking into whether the worker was wearing or was offered protective equipment.

A nasal swab from the Michigan worker tested negative for influenza in the state, but an eye swab from the patient was shipped to CDC and tested positive for the H5N1 virus, the CDC said.

The US Department of Agriculture (USDA) said it believes unpasteurized milk is the primary vector for transmitting the virus among cows, though officials do not know exactly how it spreads.

To limit transmission in cattle, the USDA in late April started requiring dairy cows to test negative before being shipped across state lines.

“It’s likely that there will be several cases that emanate from exposure to infected cows and their milk amongst farm workers,” said Dr. Amesh Adalja, an infectious disease expert at the John Hopkins Center for Health security.

“The key thing is to make sure that testing is wide enough to capture them.”