COLORADO, USA — A dairy farm worker in northeast Colorado tested positive for the H5N1 avian flu strain after being infected at his work, the Colorado Department of Public Health and Education (CDPHE) said in a release.
The man had direct contact with dairy cows that were infected with the virus, CDPHE said. The man reported his symptoms to state health officials, who then tested him for avian influenza. CDPHE's results were inconclusive, the Centers for Disease Control and Prevention (CDC) said. More specimens were sent to the CDC for additional testing, which confirmed the infection.
This case marks the fourth human avian flu case in the U.S. due to an ongoing multistate outbreak of avian flu in dairy cattle, the CDC said. The other confirmed cases were in Texas, with one case, and Michigan, with two infections.
This is the first human case of avian flu in Colorado since 2022, CDPHE said.
"It's getting more interesting now that more and more humans are testing positive. And it's not surprising because we are seeing an outbreak amongst cattle in a lot of dairy farms," 9NEWS Health Expert Dr. Payal Kohli said.
CDPHE's report of the state's first case of avian flu in a human comes as the USDA https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock reports 23 of Colorado's livestock herds have been impacted by the virus in the last 30 days.
State epidemiologist Rachel Herlihy said the spread into people isn't a surprise.
"With 25% of the herds in our state affected, we know that's potentially a large number of dairy cattle workers in the state that are being exposed to this virus. And so not unexpected that we're seeing this case," Herlihy said.
Herlihy says right now, the only people exposed to the virus are dairy workers in milking parlors who directly work with animals.
But Kohli said cattle and dairy workers becoming infected show the virus is mutating.
"We know that it's mutating because it's now in cattle, it wasn't before. We just have to hope that it doesn't mutate enough to start transmitting from human to human because that's when we would worry about exponential growth and a rapid spread," she said.
CDPHE reported in the dairy worker who caught avian flu, his only symptom was pink eye.
"Pink eye or conjunctivitis is a common symptom, so inflammation of the lining of the eye," Kohli said. "But you can also see upper respiratory tract symptoms as well as fevers and chills, muscle aches, some of the common symptoms that we see with flu."
Tamiflu was used to treat the man. Dr. Kohli says that's a typical course of treatment for flu. But, she said, if you become infected with it, even if your symptoms are mild you should quarantine.
"The more infections you have the more chances the virus gets to mutate and learn and get smarter than us. So, I would advise anyone who is infected with this particular virus to quarantine and isolate and stay away from others and make sure that until they're symptom-free, they really do stay in isolation," Kohli said.
If you're cooking, Kohli said cook meat and eggs thoroughly. Stick to pasteurized milk for now, to be safe.
"The latest information we have from the USDA and FDA, including reports that just came out this week, suggest that the milk supply is very safe. The work they are doing in looking at the effectiveness of pasteurization has all been very reassuring, so we know that commercial milk is safe," Herlihy said.
Both Herlihy and Kohli agree more avian flu cases in humans are likely to follow but that it's expected to stay in those folks working with dairy cattle and poultry. For most Coloradans, there's nothing to worry about.
"The risk to the general public is going to continue to be low," Herlihy said.
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