INDIANAPOLIS (AP) — State health officials are urging Indiana’s medical providers to be aggressive in testing patients for syphilis amid a statewide surge in the disease.

The State Department of Health said Friday that preliminary data show 357 early infectious syphilis cases diagnosed between Jan. 10 and Oct. 3. That’s a nearly 53 percent increase from the number of cases diagnosed during the same period last year.

People with early syphilis cases have had the sexually-transmitted disease less than a year. Most of Indiana’s cases this year are among men who have sex with men.

The federal government said last year syphilis cases had reached their highest level since 1995, with gay and bisexual men accounting for most of those cases.

Syphilis is a potentially deadly bacterial disease that’s curable with appropriate antibiotics.