Bird flu: Fourth human case in US confirmed in Colorado farm worker

DENVER (KDVR) — Colorado officials say a man who was only reporting symptoms of conjunctivitis recently tested positive for avian flu. He has since recovered.

This is the fourth human case of bird flu associated with U.S. dairy cows this year, according to health officials. The first was identified in March in Texas, and two more were identified in Michigan.

This case was regarding an employee at a dairy farm in northeast Colorado with direct exposure to dairy cattle that were infected with avian flu. Northeast Colorado is also where the first case of highly pathogenic avian influenza was detected on April 25.

According to the Colorado Department of Public Health and the Environment, the worker reported his symptoms to state health officials and specimens were forwarded to the Centers for Disease Control and Prevention for additional testing, which were positive for avian flu. The worker was given antiviral treatment with oseltamivir, which follows the CDC's recommendations, and has since recovered.

The Colorado Department of Public Health and the Environment said the state's last case of H5N1 in humans was in 2022 after someone was exposed to infected poultry. The virus in humans often presents with flu-like symptoms, such as a cough, congestion, sore throat and watery eyes. Eye symptoms were the only symptoms reported by the first two infected individuals who tested positive.

“The risk to most people remains low. Avian flu viruses are currently spreading among animals, but they are not adapted to spread from person to person," said Dr. Rachel Herlihy, state epidemiologist with CDPHE, in a release. "Right now, the most important thing to know is that people who have regular exposure to infected animals are at increased risk of infection and should take precautions when they have contact with sick animals."

H5N1's spread has since led to 10 dairy facilities being placed under quarantine. The bird-borne virus causes cattle to exhibit signs like low appetite, decreased milk production and abnormal colostrum-like milk.

According to CDPHE, it is safe to drink pasteurized milk and eat "properly handled and cooked dairy, beef, and poultry products," because the process kills bacteria and viruses, including avian flu.

The state health agency said people should not to touch dead or sick animals, but if it's unavoidable:

• Wear personal protective equipment including a N95 respirator, eye protection and gloves
• Wash hands with soap and water afterward
• If there's no soap and water available, use an alcohol-based hand rub

There is also an emergency rule enacted for mandatory testing of lactating dairy cattle moving interstate.