2nd human case of bird flu confirmed amid U.S. dairy cow outbreak

A Michigan farmworker has been diagnosed with bird flu, state health officials announced in a statement Wednesday, marking the second human case associated with the current outbreak in U.S. dairy cows. 

The latest patient, who had been in contact with cows presumed to be infected, had mild symptoms of an eye infection and has recovered, according to a statement shared by the Centers for Disease Control and Prevention.

"The risk to the public remains low," Michigan health officials said.

A nasal swab from the person tested negative for the virus, but an eye swab tested positive, "indicating an eye infection," the CDC said. An investigation is underway to understand more details on the worker's situation. 

The first case, which was also mild and presented as the eye infection conjunctivitis, happened in late March after a farmworker in Texas came into contact with cattle suspected of being infected. 

Since 2020, the H5N1 bird flu virus, also called HPAI or highly pathogenic avian influenza, has "caused extensive morbidity and mortality events" in animal species across the U.S., according to the Fish and Wildlife Service. The virus, carried by migratory birds, has also affected poultry flocks in numerous states.

So far, the virus does not appear to have spread from person to person, but public health officials are closely monitoring for any signs of the virus mutating to transmit more easily.

"There's no evidence that has happened yet, but that's the big concern," CBS News chief medical correspondent Dr. Jon LaPook explained earlier this month. 

"The worry would be if it changes in mutations, genetic composition, so that it can spread easily from human to human."

The detection of the virus in U.S. livestock earlier this year — which has now been confirmed in 51 dairy herds in nine states, according to the U.S. Agriculture Department — has also raised questions about food safety, especially around milk. 

Testing confirms pasteurization is working to kill the virus, and the Food and Drug Administration says the commercial milk supply is safe. 

Health officials strongly advise against drinking raw milk, despite influencers promoting it on social media.

"Do not consume unpasteurized dairy products," Dr. Nidhi Kumar recently told CBS New York. "I know there are people that are real advocates for it, but this is not the time to do it."

The Centers for Disease Control and Prevention calls raw milk "one of the riskiest foods."

"Raw milk is milk that has not been pasteurized to kill harmful bacteria," the agency's website explains. "Raw milk can be contaminated with harmful germs that can make you very sick," with symptoms including diarrhea, stomach cramping and vomiting,

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• Bird Flu