Health officials say the number of swine flu cases in Illinois has risen to more than 3,100. There have been 13 deaths in the state from the virus.

The Illinois Department of Public Health released new numbers Thursday, and the rate of new cases is continuing to slow. The tally of 3,166 probable and confirmed cases rose from last week's total by 291 cases.

Two southwestern counties are reporting their first cases.

St. Clair County's health department says a 13-year-old boy and a 45-year-old man are being treated with antiviral medication. One of the cases was confirmed last Friday; the other Wednesday.

In neighboring Madison County, health officials say a 12-year-old boy and a 32-year-old woman have the virus.