Every Human Case of Avian Flu Reported So Far

There are now 46 human cases of avian flu in the United States, according to the U.S. Centers for Disease Control and Prevention. The cases are mostly in California, with 21 cases in dairy farm workers, and Colorado, which has 10 cases, mostly poultry farm workers, and also Washington, which has 11 infected poultry workers. Globally since 2003, avian flu cases have reached 903, as of August 2024.  

The disease has proliferated in wild bird populations at more than 10,000 cases, and has spread to wild mammals far more sporadically, but cases have been found in foxes, otters, sea lions and bears. In farm animals, avian flu is spreading to and between cattle and infecting dairy farm workers. While human cases remain rare and linked to exposure to animals, health officials warn the situation — and risk level — could change at any moment.

Public Health Officials Recommend Protective Measures 

The CDC has updated its guidelines for employers to reduce risk of disease spread for workers and others who come in contact with animals. Those at risk includes poultry and dairy workers, poultry and dairy farmers, owners of backyard chickens, dairy lab employees, food processing workers who handle raw milk and slaughterhouse workers. And protective measures include proper ventilation, protective equipment, testing and isolation processes for anyone exhibiting symptoms and handwashing stations. 

An important precaution for everyone is to get your seasonal flu shot. While the current flu shot does not prevent against avian flu, public health officials say it can help reduce the risk of getting sick with seasonal and avian flu at the same time, which is an important risk reduction measure.

Highly pathogenic bird flu is thought to have first emerged in U.S. poultry in 1924, which “caused severe losses in live bird markets in New York City,” according to the Centers for Disease Control. While there has been no documented human-to-human spread of avian flu anywhere around the world, there is some debate as to the origins of the deadly 1918 flu pandemic that killed 20-40 million people globally. The CDC writes that the influenza responsible did have “genes of avian origin,” as did a 1957 pandemic that killed 1.1 million people worldwide.

This piece was last updated November 7, and was originally published February 23, 2023.