The APHIS Website documenting outbreaks of HPAI confirmed a cluster of cases involving 1.7 million hens in Merced County, CA. on December 5th. This follows previous outbreaks among turkey, broiler growing and egg farms in the state and following outbreaks in Washington State and Oregon and with concurrent cases in British Columbia associated with fall migration of waterfowl in the Pacific Flyway. An added complication in 2024 is possible extension from infected dairy herds in proximity to poultry farms.
The latest reported outbreak on December 9th involved a complex with 4.5 million hens in Sioux County, IA. The production of this farm was contracted to Michael Foods a subsidiary of Post Holdings. According to an SEC-mandated disclosure the affected complex represented 12 percent of controlled production for Michael Foods. This case suggests dissemination of H5 virus in the Mississippi Flyway. A second complex in Sioux County is awaiting confirmation of the diagnosis
Additional details will be posted when available including:-
- whether pullets were affected,
- the results of whole genome sequencing of the H5N1 isolate,
- duration of depopulation of the complex supervised by APHIS
- results of zonal surveillance of poultry flocks including trapped wild birds and mammals
- findings from epidemiologic investigations to determine the route of infection.