A Michigan farm worker has been diagnosed with bird flu, state officials announced Wednesday, making it the second human case linked to the outbreak in cows.
Authorities said the individual was infected with the virus, called H5N1, after exposure to infected livestock. The individual had only mild symptoms and made a full recovery, authorities said. They did not provide additional details in order to protect the privacy of the farm and farm worker, they said.
In 2022, a person in Colorado with direct exposure to infected poultry became the first confirmed human case of H5N1 in the United States. Last month, the Centers for Disease Control and Prevention reported an H5N1 virus infection in a Texas dairy worker — the first case associated with the outbreak in cows.
The detection of this latest case does not suggest that avian flu is widespread in humans, officials said, adding that the risk to the general public remained low.
“This virus is being closely monitored and we have not seen any signs of sustained human-to-human transmission at this point,” Dr. Natasha Bagdasarian, Michigan’s chief medical officer, said in a statement.
According to the CDC, a nasal swab taken from the individual tested negative for the H5N1 virus, but an eye swab sent to the agency tested positive. Like the infected person in Texas, the Michigan patient reported only eye symptoms, the CDC said.
Veterinarians have reported that some farmworkers have developed flu-like symptoms, but few farmers and farmworkers have agreed to be tested to determine the cause. In Michigan, farmworkers exposed to infected animals were asked to report even mild symptoms, and testing for the virus was made available, Dr. Bagdasarian said.
The virus has been detected in 51 dairy herds in nine states, according to the U.S. Department of Agriculture. But the epidemic is believed to be much more widespread. Michigan officials reported four infected herds that were not included in the federal count. The Food and Drug Administration found traces of the virus in 20 percent of dairy products sampled on grocery store shelves in 17 states.
The virus was likely transmitted from wild birds to dairy cows during a single spread event in the Texas Panhandle as early as last December, scientists said. Federal authorities did not confirm the first infections until late March.
Cows were not thought to be susceptible to the virus, and the virus spread among them undetected, with no visible symptoms, studies show. The virus has been detected in some dairy herds with no known links to the affected farms, suggesting that the virus has spread among asymptomatic cows and that there are infected herds that have not yet been identified.
The virus may have spread between cows largely through contaminated milk, which contains high levels of virus. The virus has also spread from dairy farms to poultry farms, possibly through the movement of contaminated vehicles or equipment. Transportation of infected cows from Texas may have spread the infection to North Carolina and Michigan.
Over the course of the outbreak, the virus has acquired dozens of new mutations, some of which could make it better able to spread between species.
The Texas farmworker diagnosed in April suffered from severe conjunctivitis but made a full recovery, CDC officials reported earlier this month. Authorities were unable to test the individual’s social contacts.
Farm owners are reluctant to test their workers or livestock, fearing financial consequences. And barring extraordinary circumstances, federal and state authorities cannot force farmers or farmworkers to get tested.
Noah Weiland reports contributed.
News Source : www.nytimes.com
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