An unidentified dairy worker in northeastern Colorado became the fifth person in the US with a confirmed highly pathogenic bird flu infection, but he had only mild symptoms.
The person, an adult male, developed conjunctivitis, or pink eye, after exposure to infected cows, the Colorado Department of Public Health and Environment said Wednesday. He took an antiviral drug as a precaution and has recovered.
State officials have not released other details, including the name of the farm, how the virus may have jumped from the cows to the worker, and whether authorities have tested other people who lived or worked with the man.
The first person to test positive for the highly pathogenic H5N1 bird flu in the United States was a poultry worker in Colorado in 2022. One dairy worker in Texas and two in Michigan contracted the virus this spring. All four cases were mild. (The virus got its name because it causes a high mortality rate among poultry.)
Normally, H5N1 circulates among wild birds, sometimes spreading to chickens and other domestic poultry. Sometime in December or January, the species made the jump to dairy cattle and has since spread to herds in at least twelve states, including Colorado. Because testing is largely voluntary, no one can be sure whether the virus has reached other states.
The virus generally appears to cause mild symptoms in cattle, but has proven fatal in domestic cats and some wild mammals. Right now it’s not well adapted to spreading from person to person, but every time it infects someone it gets a new roll to pick up mutations that allow it to take hold in people.
State epidemiologist Dr. Rachel Herlihy said people who don’t interact closely with livestock or birds are at low risk. To protect themselves, people should not touch sick or dead animals, and if they must, they should wear gloves, goggles and an N95 mask and wash their hands afterwards.
“At this time, the most important thing to know is that people who are regularly exposed to infected animals are at increased risk of infection and should take precautions if they come into contact with sick animals,” she said in a news release.
The department also recommended drinking raw milk. Pasteurized milk and fully cooked beef and chicken are safe.
If you work with animals that may be infected and develop flu-like symptoms or eye inflammation, call the state health department at 303-692-2700 to arrange tests and medications if necessary.
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