New cases of highly pathogenic avian influenza (HPAI) have been confirmed in counties with previously reported cases, according to information on the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) website.

One of the new cases is in Cecil County, Maryland, while the other is in Charles Mix County, South Dakota.

South Dakota case

The latest confirmed case of HPAI in Charles Mix County involves a commercial flock of 36,000 turkeys, and that case was confirmed on March 12.

The other case of HPAI in that county was in a commercial flock of mixed poultry, according to APHIS. While APHIS stated that 47,330 birds were susceptible, the agency did not elaborate on what species of poultry were involved in that flock, information from the World Organisation for Animal Health (OIE) revealed that there were turkeys in that flock. That case was confirmed on March 5.

The two Charles Mix County cases are the only HPAI cases in commercial poultry reported to date in South Dakota.

Maryland case

The latest case in Cecil County was confirmed on March 10 and involved a commercial layer flock that included 664,061 chickens.


The previous case in that county was confirmed on March 4 and also involved a commercial layer operation. That flock included 496,272 chickens.

To date, there have been three confirmed HPAI cases in Maryland. The other case was in Queen Anne’s County, and involved a flock of 150,000 broiler chickens.

Elsewhere in North America

In addition to South Dakota and Maryland, HPAI has been confirmed in commercial poultry flocks in the U.S. states of Indiana, Kentucky, Missouri, Iowa and Delaware. It has also appeared in a commercial flock in the Canadian province of Nova Scotia.

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

Read our ongoing coverage of the global avian influenza outbreak.