The first case of highly pathogenic avian influenza (HPAI) in California in 2022 was confirmed on August 22.

The affected flock was a commercial broiler breeder flock, located in Fresno County. There were 33,900 chickens in that flock, according to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).

According to the California Department of Food and Agriculture (CDFA), the premises is currently under quarantine, and the birds have been euthanized to prevent the further spread of the disease.

CDFA also announced that HPAI was detected in a backyard flock in Contra Costa County, as well.

Prior to the Fresno County and Contra Costa County cases, California had only had two confirmed cases in California, both of which involved backyard poultry. Those cases were in Butte County and Sacramento County. Following the detection of the virus in Butte County, officials in the county declared a local health emergency. However, avian influenza cases in backyard poultry should not have an impact on international poultry trade, in accordance with standards set by the World Organisation for Animal Health (WOAH).

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HPAI cases in the United States had been slowing down during the summer months, with the country going nearly a month without a case of HPAI in a commercial flock. Before this latest case was confirmed, the last confirmed detection of HPAI in the United States commercial flock occurred on July 26 in a commercial turkey flock in Sanpete County, Utah. There were 12,700 turkeys in that flock.

In addition to California and Utah, HPAI has been confirmed in 2022 in commercial poultry in the states of Michigan, Wisconsin, Oklahoma, Minnesota, North Dakota, South Dakota, Nebraska, Kansas, Iowa, Missouri, Kentucky, Indiana, Colorado, North Carolina, Pennsylvania, Delaware and Maryland. The virus has also been found in commercial game bird operations in Texas, New York and South Dakota.

To learn more about HPAI cases in North American commercial poultry flocks, see an interactive map on WATTPoultry.com.

Read our ongoing coverage of the global avian influenza outbreak.