The progression of the species-jumping disease has been unprecedented, including the first-ever U.S. cases of infections in dairy cattle and heightened pandemic risks.

The Centers for Disease Control and Prevention are monitoring the bird flu situation in the United States. Here's what to know and how to stay safe.

A newly identified strain of bird flu, H5N9, discovered at a California duck farm, has prompted concerns about the possibility of a larger outbreak, The Washington Post reported Jan. 29. Health experts are monitoring the situation, particularly the potential for genetic mutations that could make the virus more easily transmissible among humans.

H5N9 is a rare subtype of the influenza A virus that can cause highly pathogenic avian influenza (HPAI), also known as bird flu. It's a reassortment strain that originated from the H5N1, H7N9, and H9N2 subtypes.

H5N1 bird flu hits Georgia’s poultry industry marking the first commercial outbreak in the state Learn CDC prevention tips to protect public health and livelihoods

The H5N1 Avian influenza is decimating bird populations around the world. More than 136 million birds have been affected in the US since the disease arrived in 2022. More than 5 million egg-laying chickens died in the first 16 days of 2025.

Learn more about how a vaccine could help prevent the spread of the avian flu virus but may also cause the virus to evolve faster.

The H5N9 strain of avian influenza is much more rare than the H5N1 which has been responsible for most of the reported human cases and the first human death.

"The H5N1 virus is widely circulating across North America, and these viruses can reassort in species that are susceptible to influenza viruses," Tompkins said. Has H5N9 been seen in the U.S. before?

The findings come at a time when outbreaks of bird flu -- a different subtype of the ... of the highly pathogenic avian influenza (HPAI) H5N1 influenza virus currently circulating

This strategic initiative responds to escalating concerns over the spread of the highly pathogenic H5N1 avian influenza A virus. Recent H5N1 outbreaks have spread beyond birds to involve mammals ...