COLUMBIA, S.C.- South Carolina Department of Health and Environmental Control officials say 13 people in the state have tested positive for the swine flu virus.

The lab results were announced by the U.S. Centers for Disease Control and Prevention (CDC) Thursday.

DHEC officials say the 13 people who have the virus are all associated in some way with a recent school trip to Mexico. The trip was sponsored by a private school in Newberry.

Jerry Gibson, M.D., chief of DHEC’s Bureau of Disease Control, said they have been asked to voluntarily isolate themselves for a short time.

Anyone who was exposed to them is asked to voluntarily quarantine themselves at home. Those in isolation will receive appropriate care, Gibson said.

So far, DHEC has tested 22 residents for the virus.

CDC workers also say there is one confirmed case of swine flu in west Georgia. The woman is from Kentucky and was visiting the state.