For the first time since 2017, H7N9 bird flu has been reported on U.S. poultry farms

The United States has seen its first outbreak of the highly deadly H7N9 bird flu on poultry farms since 2017. The United States is still dealing with another strain of bird flu that has infected humans and sent egg prices to record highs.

The Paris-based World Organisation for Animal Health (WOAH), citing US officials, said on Monday that the latest H7N9 outbreak occurred at a farm in Noxupie County, Mississippi, that raises 47,654 commercial broilers.

"Highly pathogenic avian influenza (HPAI) H7N9 virus with North American wild bird ancestry has been detected in a commercial broiler flock in Mississippi," the report said. Culling of infected poultry is currently underway."

Usda is working with state animal health and wildlife officials to conduct a comprehensive epidemiological investigation and enhance surveillance in response to this outbreak.

The spread of bird flu has severely affected poultry herds worldwide, disrupting supply chains and driving up food prices. Bird flu has also spread to mammals, including cows in the United States, raising fears among governments of a new pandemic.

The strain of bird flu that has caused the most damage to poultry and killed one person in the United States in recent years is H5N1.

However, the World Health Organization says H7N9 has been more deadly since it was first detected in 2013, killing nearly 40% of those infected.