The U.S. Department of Agriculture says pigs in a commercial herd in Indiana have tested positive for the swine flu virus.

This is the first instance of swine flu in a commercial herd in the United States.

The USDA says it discovered four tissue samples that tested positive for the virus using its swine surveillance program.

The USDA says the pigs as well as the people caring for the pigs have recovered. The sample was collected in late October.

Last month, tests confirmed several show pigs at the Minnesota State Fair contracted the virus, also known as H1N1.