Person had direct contact with infected cattle; public health experts say the risk to the public is low
The Colorado Department of Public Health and Environment, in coordination with the Centers for Disease Control and Prevention and Colorado Department of Agriculture, has identified a human case of avian influenza H5 infection associated with a multi-state outbreak of the virus in dairy cattle.
The adult male had mild symptoms, reporting only conjunctivitis (pink eye). He reported his symptoms to state health officials, who tested him for influenza at the State Public Health Laboratory. Specimens forwarded to CDC for additional testing were positive for avian flu. CDPHE gave the individual antiviral treatment with oseltamivir in accordance with CDC guidance. He has recovered. This case is an employee at a dairy farm in northeast Colorado who had direct exposure to dairy cattle infected with avian flu. To protect patient privacy, additional details are not being provided.
“Our partnership with the Colorado Department of Agriculture has been crucial in disseminating information to dairy farmers across the state,” said Jill Hunsaker Ryan, executive director, CDPHE. “Coloradans should feel confident that the state is doing everything possible to mitigate the virus.”
It is safe to drink pasteurized milk and eat properly handled and cooked dairy, beef, and poultry products in the United States. The proper handling and cooking of poultry, meat, and eggs kills bacteria and viruses, including avian flu viruses. An updated study released earlier this week by FDA and USDA reinforced the safety of the commercial milk supply.
“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. 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,” said Dr. Rachel Herlihy, state epidemiologist, CDPHE.
Coloradans should not touch sick or dead animals. If you must handle sick or dead animals, wear recommended personal protective equipment, including an N95 respirator, eye protection, and gloves. If possible, wash your hands with soap and water afterward. If soap and water are not available, use an alcohol-based hand rub.
Nationally, there have been three other cases of avian flu in humans associated with the ongoing multi-state outbreak in dairy cattle that was first identified in the U.S. in March 2024. The last human detection of H5N1 in Colorado was in 2022 in someone who was exposed to infected poultry.
“We continue to work closely with the Colorado Department of Agriculture, local public health agencies, and CDC as we monitor this virus to protect all Coloradans,” said Scott Bookman, senior director of public health readi- ness and response, CDPHE. “While it’s rare for people to become infected with avian flu viruses, direct exposure to infected animals increases that risk.”
If you work with dairy cows that may have avian flu and you start to feel sick, call CDPHE at 303-692-2700 (after normal business hours: 303-370-9395). The Department can help you get a flu test and medicine if needed. More information about avian flu in humans is available at cdphe.colorado.gov/animal-related-diseases/hpai-h5n1.
The Colorado Department of Agriculture has been working on a state response to the highly pathogenic avian influenza (HPAI) outbreak since 2022. CDA has been coordinating with state and federal partners, including CDPHE and the U.S. Department of Agriculture, to confirm and respond to cases. Avian flu is a reportable disease in Colorado and must be reported to the State Veterinarian’s Office. CDA has also adopted an Emergency Rule that requires mandatory testing of lactating dairy cattle moving interstate. More information about CDA’s response to the outbreak can be found at ag.colorado.gov/HPAIresponse.
