The fourth human case of bird flu linked to the current dairy cow outbreak was confirmed on Wednesday in a dairy worker in Colorado, according to the Centers for Disease Control and Prevention.
Previously, one human case had been reported in Texas, and two human cases were reported in Michigan.
As with the previous cases, the patient is a dairy farm worker who came into contact with cows that tested positive for the H5N1 strain of bird flu, or avian influenza.
The worker was previously being monitored because of their exposure to infected cattle and reported symptoms to state health officials.
Testing results were inconclusive at the state level, but the federal health agency said specimens forwarded to the CDC for additional testing were positive for influenza A.
The patient reported eye symptoms only. They received treatment with oseltamivir, an antiviral drug used to treat influenza, and have since recovered.
The CDC said the risk to the general public remains low, but advises people to avoid close, long or unprotected exposures to sick or dead animals. People are also advised to avoid unprotected exposure to animal excrement, litter, unpasteurized milk or materials that have been touched by — or close to — animals with suspected or confirmed bird flu.
In early March, the U.S. Department of Agriculture announced a bird flu strain that had sickened millions of birds across the U.S. was identified in several mammals this year.
A few weeks later, federal and state public health officials said they were investigating an illness among primarily older dairy cows in Kansas, New Mexico and Texas and causing symptoms including decreased lactation and low appetite.
