State and Butler County health departments say preliminary laboratory tests indicate possible H3N2 variant flu virus, which can be contracted by humans from being around infected hogs. Officials say all 10 had contact with hogs at the Butler County Fair, which ended last weekend.

The U.S. Centers for Disease Control and Prevention is also investigating, but hasn't confirmed swine flu.

Health officials say all 10 are recovering from their illness. Swine flu symptoms include cough, sore throat, fever and body aches.

Indiana authorities last week said they were investigating similar cases involving four people who had swine contact at a northwest Indiana fair.