Third person tested positive for bird flu in US, CDC says

A third person has now tested positive for H5N1 in the US, the second case discovered in Michigan, the US Centers for Disease Control and Prevention (CDC) announced on Thursday.

A farm worker who had contact with sick cows tested positive for the virus. This new case does not appear to indicate human-to-human transmission of the highly pathogenic bird flu, as it was discovered at a different farm than the previous case in Michigan, officials said.

Only 39 people in the US were tested for H5N1 during the 2024 outbreak. according to to the CDC. More than 350 people are being monitored for symptoms, including 220 people in Michigan, officials said.

H5N1 was also recently present detected in the muscles of a dairy cow intended for beef consumption. No additional virus particles were found in other beef samples and the contaminated meat did not enter the food supply, U.S. Department of Agriculture (USDA) officials said.

The USDA also announced $824 million in new funding Thursday to protect the health of livestock during this outbreak. The agency has not yet announced plans to compensate affected farms for lost production, which could spur case reporting.

This is the first time during the U.S. outbreak that a person with H5N1 has shown respiratory symptoms, unlike the previous two cases involving only conjunctivitis, commonly known as “pink eye.”

The respiratory symptoms are concerning because they “increase the likelihood that someone will be exposed to the virus compared to conjunctival symptoms,” Dr. Nirav Shah, deputy director of the CDC, told reporters Thursday. “Someone who coughs is more likely to transmit the virus than someone with an eye infection such as conjunctivitis.”

But so far no close contacts, including other farm workers, have reported symptoms, he said.

“To date, none of the close contacts of this person have developed or reported symptoms and have been offered Tamiflu,” Shah added.

The person has been given antiviral drugs for the flu and is “recovering,” he said.

Officials have “not seen anything in our genetic analysis so far that suggests changes in the virus that would make it easier to transmit among people,” Shah said.

Noting that Michigan’s second human case was not unexpected, Shah said, “To their credit, the Michigan team is actively identifying employees who may be ill, and this helps us ensure these employees receive appropriate treatment. ”

While many farmers and farmworkers across the country have been reluctant to get tested, Michigan has been an outlier. The cases of bird flu in humans were detected through their monitoring program which includes daily text messages to monitor symptoms – even mild symptoms like eye irritation.

Michigan officials are also conducting serological surveys to understand whether farmworkers have previously been infected with H5N1.

Shah emphasized the importance of using personal protective equipment for workers in close contact with animals, but acknowledged the difficulties of wearing such equipment during hot summer weather.

The CDC asked states to continue monitoring for flu through the summer — a time when monitoring is typically slower due to low viral circulation.

“CDC has recently taken steps to improve influenza surveillance during the summer. Specifically, CDC is working with commercial laboratories to increase their admission of influenza-positive test specimens to public health laboratories during this normally low summer season of influenza activity,” Shah said.

The CDC has ordered 4.8m H5N1 vaccines that seem to be a good fit for this strain, and they are considering vaccinating farmworkers and others at risk.

At this time, the CDC does not recommend H5N1 vaccination for anyone, not even agricultural workers.

“Right now, there is no one for whom vaccination is recommended,” said David Boucher, director of infectious disease preparedness and response at the Administration for Strategic Preparedness and Response. “But that is of course something we are always looking for.”