ST. LOUIS – Health officials in two Missouri cities – St. Louis and Springfield – are concerned about a rising number of syphilis cases, especially among gay and bisexual men, many of whom also have the virus that causes AIDS.

Through the first eight weeks of 2005, St. Louis had 26 presumed cases of syphilis, Missouri Department of Health epidemiologist Frank Lydon said Thursday. Eighteen of those with the illness have been interviewed – 12 were men who told investigators they had sex with men, and all 12 were also HIV-positive, Lydon said.

Last year, St. Louis reported 65 syphilis cases. Thirty-four involved men who had sex with men, and 17 were also infected with HIV.

Springfield hadn’t seen any new syphilis cases for several years until last year, when five people were infected with the disease, said Clay Goodard, administrator of community health for the Springfield/Greene County Health Department. Of those five, three were men who had sex with men and two were also infected with HIV.

Already this year, Springfield has reported six new cases, all involving gay and bisexual men. One of those men also has HIV.

Health officials said the co-infection link is no coincidence. Those with syphilis are at 200 percent to 500 percent greater risk of contracting HIV if exposed to the virus.

The syphilis lesion “becomes a moment of opportunity for the HIV virus to find its way into your system,” Lydon said. “It’s an open, healing sore. You don’t need much more than that for the virus to enter your body.”

Syphilis is contracted through vaginal, anal and oral sex. If left untreated, it can cause dementia, blindness, even death.

Other U.S. cities, including Chicago, Seattle, San Francisco, Miami and New York, have also seen syphilis outbreaks among gay and bisexual men in recent years, according to the Centers for Disease Control and Prevention in Atlanta. In San Francisco, syphilis cases among that demographic group numbered just four in 1998, but 260 in 2002.

Missouri health officials and safe-sex advocates fear many in the gay community – especially younger men – are beginning to view HIV and AIDS as a chronic but manageable disease and are becoming blase about taking steps to avoid sexually transmitted diseases.

“This is the first generation that doesn’t see the death,” said Thomas Adams, executive director of the AIDS Foundation of St. Louis. “They’re tired of safe-sex messages.”

Goodard agreed.

“You have a whole new generation of gay men who are not worried about becoming infected with HIV,” he said. “That opens the door for other diseases we’ve always fought such as syphilis and gonorrhea.

“That’s troubling because once you get it into a population, it’s difficult to eradicate.”

Efforts are under way in both St. Louis and Springfield to try and slow the surge in syphilis. Both cities and the state health department have issued alerts to let residents know of the risk.

In Springfield, the health department is developing posters that will go up in gay bars and at adult bookstores.

In St. Louis, the Guardian Project, a collaborative effort of the St. Louis Health Department, the AIDS Foundation and other groups, is targeting gay men through billboards, bus stop kiosks and other advertising. Guardian volunteers each weekend are taking their safe-sex message to nightclubs and gay bars.

“We’re trying to educate St. Louisans to engage in safer behavior, whether that means abstaining or using a condom,” said Duane Westhoff, a 28-year-old Guardian volunteer.