The USDA said Sunday that new cases of bird flu have been detected in a commercial chicken flock in Pennsylvania and a domestic flock in Utah, with the disease now spreading to more than 30 states in the country.
Earlier this month, the ministry said it was looking at vaccines as an option to protect poultry from the deadly bird flu as the country grapples with its worst outbreak since 2015. February.
The USDA said federal and state officials are working together to step up monitoring and testing in areas around infected swarms.
US authorities have said that newly discovered cases of highly pathogenic avian influenza are not an immediate public health problem.