Bird Flu Strains Trigger Alarms in US

Multi-state outbreaks demand pre-emptive action on poultry and dairy farms.

Since the spring of 2024, the United States has seen the emergence of new, highly pathogenic avian influenza (HPAI) H5N1 genotypes, specifically clade 2.3.4.4b. These genotypes have led to unprecedented outbreaks affecting both poultry and dairy farms across multiple states and have also resulted in human infections, raising concerns among health officials.

H5N1’s Origins and Spread

First detected in chickens in **Scottland** in 1959, HPAI H5N1 has since spread globally, evolving into diverse lineages and clades through migratory birds and terrestrial avian hosts. The virus was reported in domestic waterfowl in Southern **China** in 1996, known as A/Goose/Guangdong/1/1996. It caused the first known human infections in **Hong Kong** in 1997, with 18 cases and 6 deaths.

Call for Preparedness

The outbreak situation emphasizes the critical need for pre-pandemic preparedness to effectively control HPAI H5N1 in both poultry and dairy farms in the US. According to the CDC, as of June 5, 2024, 12 human cases of HPAI A(H5N1) virus have been reported in the U.S., linked to dairy farm exposures.