UNDATED 9CNN) -- The Centers for Disease Control and Prevention says a new strain of the swine flu has been found, and at least 145 cases have been reported in four states.

As many as 120 cases are in Indiana.

State officials there have been removing hogs from fairgrounds as a precaution.

An epidemiologist from the CDC says many of the cases are a result of human-to-pig contact at fairs.

The CDC says it expects the number of cases from the H3N2 variant will grow in the coming weeks.

Officials also say preliminary steps have been taken to develop a vaccine for the new strain.