A fourth person has tested positive for bird flu in the outbreak linked to dairy cows, this time in Colorado.
The Centers for Disease Control and Prevention said Wednesday that the patient, a dairy worker at a farm where cows had also tested positive for the virus, had eye symptoms and has recovered after getting the antiviral drug Tamiflu.
The case mirrors the course of illness seen in two earlier cases in this outbreak, in Texas and Michigan dairy workers. The only symptoms either developed was pink eye. A third patient, also in Michigan, did develop upper respiratory symptoms, including sore throat, cough and congestion.
All of the patients have recovered, and none were connected to one another.
“Based on the information available at this time, this infection does not change CDC’s current H5N1 bird flu human health risk assessment for the U.S. general public, which the agency considers to be low,” the agency said in a news release Wednesday.
There is no evidence, the CDC said, of increased flu-like illnesses that would indicate that the virus — a strain called H5N1 — is spreading widely in people.
Since the outbreak was first detected in March, more than 780 people exposed to sick cows have been monitored, and 53 have been tested for the virus, the CDC said Tuesday in a briefing with reporters.
Federal health officials said that 4.8 million doses of a vaccine for this particular flu strain could be available in the coming weeks. Drugmaker Moderna is also in the early stages of an mRNA vaccine for bird flu.
As of Wednesday, 139 herds in 12 states had been affected, according to the Department of Agriculture.
The CDC recommends that anyone in contact with dairy cattle wear protective equipment, including safety glasses, waterproof aprons and boots that can be sanitized. Health officials also strongly warn against drinking unpasteurized raw milk. Pasteurization has been shown to neutralize the virus in milk samples.
