The Centers for Disease Control and Prevention (CDC) announced Wednesday that a second H5N1 bird flu case has been identified by officials.
A 55-year-old Michigan dairy worker became ill after working with H5N1-infected cattle, the CDC said in a press release. While an upper respiratory tract sample tested negative, a specimen from his eye confirmed the H5N1 bird flu infection.
A Texas farm worker was diagnosed with the disease in March. Both the Michigan and Texas patients suffered from conjunctivitis, or pink eye. Neither showed signs of a respiratory infection.
"Conjunctivitis (eye infection) has been associated with previous human infections with avian influenza A viruses and is part of the current CDC case definition for A(H5N1) surveillance," the CDC explained in a Wednesday press release.
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"While it’s not known exactly how eye infections result from avian influenza exposures, it may be from contamination of the eye(s), potentially with a splash of contaminated fluid, or touching the eye(s) with something contaminated with A(H5N1) virus, such as a hand."
The Texas case marked the first human case of H5N1 bird flu in the United States. Globally, it was the first time a human caught H5 bird flu from a cow.
The United States Department of Agriculture (USDA) has found that at least 49 dairy herds across nine states have been exposed to H5N1. On Wednesday, the CDC maintained that the health risk that H5N1 bird flu poses to humans is still low.
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"Based on the information available, this infection does not change CDC’s current H5N1 bird flu human health risk assessment for the U.S. general public, which the agency considers to be low.," the CDC said. "However, this development underscores the importance of recommended precautions in people with exposure to infected or potentially infected animals."
Officials are still monitoring the outbreak, but maintain that pasteurized milk is safe to drink.
"I can say without reservation that our commercial milk and meat supplies are safe," USDA official Eric Deeble said during a briefing on May 16. "At no time were animals that are sick from H5N1 or any other animal disease permitted to enter into our food supply."
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The CDC is encouraging Americans to avoid exposure to dead animals and animal waste. Officials also discourage drinking raw milk.
"Following these recommendations is central to reducing a person’s risk and containing the overall public health risk," the organization advised.
Fox News Digital's Melissa Rudy contributed to this report.