Fourth human bird flu case tied to dairy cow outbreak reported

July 3, 2024

The Centers for Disease Control and Prevention (CDC) reported on Wednesday the fourth human case of bird flu linked to the ongoing dairy cow outbreak in the country, marking the first such case reported in Colorado.

All four cases were reported in people who work on dairy farms where cows tested positive for the H5N1 strain of the virus. Since March, two cases have been identified in Michigan and one case identified in Texas. The cases are all unrelated, the CDC said.

The Colorado man, as with the first two human patients, reported only pink eye symptoms, which the Colorado Department of Public Health and Environment (CDPHE) described as “mild.” In the third case, identified in Michigan in late May, the person experienced respiratory symptoms including cough without fever and eye discomfort with watery discharge.

The Colorado patient took the antiviral, Tamiflu, and has recovered, the CDC said.

The CDC said the risk to the general public remains low. There is a greater risk, however, to people with “close or prolonged, unprotected exposures to infected birds or other animals (including livestock), or to environments contaminated by infected birds or other animals,” according to the CDC.

“The risk to most people remains low,” CDPHE state epidemiologist Rachel Herlihy said in a statement. “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.”

The Colorado man was being monitored, as he is a farmworker who had exposure to infected cattle. He reported his symptoms to state health officials, who conducted tests that were inconclusive. The CDC conducted tests that came back positive.

The CDC has been monitoring states’ flu surveillance systems, “and there has been no sign of unusual influenza activity in people, including in syndromic surveillance,” according to the CDC.

Still, health officials are warning the public to be vigilant about only drinking milk that is pasteurized and only eat “properly handled and cooked dairy, beef, and poultry products.” The CDPHE warned Coloradans not to touch sick or dead animals. If they must do so, the CDPHE said, people should wear personal protective equipment including an N95 respirator, eye protection and gloves.