A man working on a dairy farm in northeast Colorado has become the fourth human in the United States to test positive for bird flu this year.  He had direct contact with infected cattle, and his symptoms included pink eye.

The Colorado Department of Public Health and Environment reports that in coordination with the U.S. Centers for Disease Control and Prevention and the Colorado Department of Agriculture, it has identified a human case of avian influenza H5 infection associated with a multi-state virus outbreak 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 following CDC guidance. He has recovered.” The report said. “This case is an employee at a dairy farm in northeast Colorado who had direct exposure to dairy cattle infected with avian flu.”

Additional details were not provided to protect patient privacy, and the state wants the public to take this information on faith. Three others who worked with cattle in Michigan and Texas suffered from bird flu earlier in this year and recovered. So did a Colorado poultry worker in 2022.

“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 of CDPHE. “Coloradans should feel confident that the state is doing everything possible to mitigate the virus.”

According to CDPHE, it is safe to drink pasteurized milk and eat properly handled and cooked dairy, beef, and poultry products in the United States. 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 the FDA and USDA reinforced the safety of the commercial milk supply. However, health officials continue to warn against drinking raw, unpasteurized milk.

The avian flu outbreak has so many moving parts that the Centers for Disease Control and Prevention keeps many of them on an ever-changing scoreboard.

As of July 1, it shows poultry kills at 97, 263,548

States involved in the outbreak that began early in 2022: 48

As of July 1, dairy herds with infections: 136 in 12 states

And 9,523 wild birds have been detected in all 50 states with the avian flu virus.

Experts were caught off guard when, since about March, avian flu has been found in one dairy herd after another.  The U.S. Food and Drug Administration (FDA) recently reported that pasteurized grocery store milk remains safe from the highly pathogenic avian virus H5N1,

Those findings were based on more recent studies that found some infectious bird flu remained after typical pasteurization. More recent research replicated commercial pasteurization procedures and found that milk from the dairy case is safe. Those who consume raw milk without pasteurization cannot say the same thing.

July announced that the drugmaker Moderna is getting $176 million from the U.S. government to develop a messenger-RNA-based bird flu vaccine for humans. The H5 vaccine is in clinical development, and phase 3 trials could begin in 2025.

This action came after the mid-June disclosure that there is little or no natural immunity in humans to the H5N1 avian flu virus. Through blood tests, the Centers For Disease Control showed “extremely low to no population immunity” among Americans to the H5N1 avian flu virus.

The virus may be susceptible to antiviral medications, and the Department of Health and Human Services (HHS) has 4.8 million vaccine doses on order just in case.