Less than two months after a first case, a second person was infected with avian flu in the United States in connection with an epidemic of this virus which spread among the country’s cow herds, health authorities announced on Wednesday May 22. This person works on a farm where the H5N1 virus infected cows, in the state of Michigan (North), said the Centers for Disease Prevention and Control (CDC). For health authorities, however, the risk assessment for the American population remains “low”.
A first case was announced in Texas, in the southern United States, on April 1. This was “probably” the first worldwide infection of a human with avian flu via a cow, according to the CDC. A human case of avian flu had already been discovered in the country in 2022, in Colorado, but it was then an infection from poultry.
Like the Texan patient, the person infected in Michigan only showed symptoms in the eyes, the CDC specifies. Experts are concerned about the growing number of mammals infected with the disease, although cases in humans remain rare. There is currently no evidence of human-to-human transmission, but scientists fear that high circulation could facilitate a mutation of the virus that makes this type of transmission possible.
Consumption of pasteurized milk is safe
The World Health Organization (WHO) expressed “huge concern” in mid-April about the increasing spread of the H5N1 strain of avian flu to new species. Cattle herds in at least nine American states are affected by this epidemic. The first report was made on March 25.
The CDC on Wednesday again emphasized the importance of precautionary measures for people exposed to sick or potentially infected animals. These people must in particular avoid “close, prolonged and unprotected” contact with these animals, as well as with their excrement, or even with unpasteurized raw milk.
“Given the high levels of H5N1 virus in raw milk from infected cows, as well as the extent of spread of this virus among dairy cows, additional similar cases in humans may be identified,” the CDC said . But “sporadic infections in humans – without continued spread – will not change the risk assessment for the general public,” they added.
At the end of April, the US Medicines Agency (FDA) confirmed that milk sold in stores in the United States was “safe”, with the pasteurization process being “effective” in killing the avian flu virus.