DES MOINES — A state health report shows Iowa’s syphilis rate continues to climb, with 877 cases of that sexually transmitted infection last year. It marks the fourth straight year cases have risen, mirroring a national trend.

State Medical Director Robert Kruse says the reason for the increase is unclear, but he says syphilis usually begins with a painless blister that goes away on its own, so it can be harder to detect in earlier stages. “Versus someone who has chlamydia or gonorrhea,” Kruse says. “They may have pelvic pain, painful urination, discharge, other kinds of symptoms that would have people seek care.”

Iowa’s rates of chlamydia and gonorrhea dropped last year. Kruse says doctors have seen syphilis cases increase for women, which led to a rise in congenital syphilis — where a woman passes the illness to her child during pregnancy.

He says doctors should consider additional screenings for their pregnant patients who are at risk. “We’ve also recommended screening at increased intervals for the infection,” Kruse says, “so, not just during the first prenatal visit, but at that 28 to 32 week gestational visit, and then again, at delivery.”

Kruse says it’s important that Iowans recognize signs and symptoms of STIs and go in for testing if they think they may have been exposed.