A Michigan farm worker has been diagnosed with avian influenza, state officials announced Wednesday, marking the second human case linked to an outbreak in cattle.
Officials said the person contracted the virus, known as H5N1, after coming into contact with infected livestock. Officials said the person's symptoms were mild and he has now fully recovered. He said he did not provide additional details to protect the privacy of the farm and farm workers.
The first confirmed human case of H5N1 in the United States occurred in 2022 in a person who had direct contact with infected poultry in Colorado. Last month, the Centers for Disease Control and Prevention reported that a dairy worker in Texas had been infected with H5N1, the first case linked to a cattle outbreak.
Officials said the detection of the cases did not indicate bird flu was spreading among the population, adding that the risk to the general public remained low.
“This virus is being closely monitored and there are currently no signs of sustained human-to-human transmission,” Michigan Medical Director Dr. Natasha Baghdasarian said in a statement.
According to the CDC, the person's nasal swab tested negative for the H5N1 virus, but an eye swab sent to CDC tested positive. Like the Texas case, the Michigan patient reported only eye symptoms, according to the CDC.
Veterinarians have reported that some farm workers have developed flu-like symptoms, but few farmers or farm workers have agreed to be tested for the cause. In Michigan, farm workers who have had contact with infected animals are being asked to report even mild symptoms, and testing for the virus is available, Dr. Baghdasarian said.
The virus has been detected in 51 dairy herds in nine states, according to the U.S. Department of Agriculture. However, the outbreak is believed to be more widespread. Michigan officials reported four clusters of infections that are not included in the federal tally. The Food and Drug Administration found traces of the virus in 20% of dairy products sampled from grocery store shelves in 17 states.
Scientists say the virus likely jumped from wild birds to dairy cows in a single spillover incident in the Texas Panhandle as early as December. Federal authorities did not confirm the first infection until late March.
Cows are not thought to be susceptible to the virus, and the study found that the virus spread unnoticed among them without any visible symptoms. The virus has been detected in some dairy herds with unknown links to affected farms, and there is evidence that the virus is circulating among asymptomatic cows and that there are infected herds that have not yet been identified. It suggests.
The virus may have spread primarily among cows through contaminated milk containing high concentrations of the virus. The virus may also have spread from dairy farms to poultry farms through the movement of contaminated vehicles or equipment. Transport of infected cattle from Texas may have spread the infection to North Carolina and Michigan.
During the outbreak, the virus has acquired dozens of new mutations, including ones that may make it more adept at spreading between species.
A Texas farm worker diagnosed in April had severe conjunctivitis but has made a full recovery, CDC officials reported earlier this month. Authorities were unable to test the person's social contacts.
Farmers have been reluctant to test their workers or cattle for fear of financial repercussions, and federal and state authorities cannot force farmers or farm workers to get tested unless there are special circumstances.
Noah Weiland Contributed to the report.
