See how syphilis rates are spiking across the country

Health officials declared a syphilis outbreak last month in Las Vegas area, where cases of the sexually transmitted disease have more than doubled since 2014. Just a few weeks later, a similar outbreak made headlines in Fresno County, Calif.

But those outbreaks aren’t isolated. Syphilis is on the rise in many cities and states across the country. The number of cases of the bacterial disease climbed by 15 percent from 2013 to 2014. In 2014, the most recent year of data available, there were 63,450 new cases of the disease nationwide.

Syphilis is a bacterial infection that spreads from person to person, typically through sexual contact. It’s also possible for a pregnant woman to spread syphilis to her unborn child. The condition presents as a sore on the genitals or in the mouth, and if untreated for a few weeks or months, can cause rashes on the skin, fever, and fatigue.

The number of US cases stayed relatively stable from 2010 until 2014, when the figures started to creep up. Health officials say there’s no obvious explanation for why, although rates of other sexually transmitted diseases are increasing, too.

Health officials say they are eyeing a handful of reasons, including increasing PrEP use among men who have sex with men. PrEP, or pre-exposure prophylaxis, is a pill taken daily to prevent HIV infection in people who are at risk of getting the virus. Officials are concerned that people taking PrEP might not realize it doesn’t protect against other STDs, and engage in sexual activity that puts them at greater risk for contracting infections like syphilis.

If infection is caught early on, the condition is easy to treat with a simple dose of penicillin or another antibiotic. But if it goes untreated for years, it can cause damage to internal organs.

The Centers for Disease Control and Prevention runs a program to dole out grants to state and local programs to provide their citizens with STD prevention resources. But since the data also show that rates of syphilis can vary dramatically from one area to the next, the CDC says it is allowing some flexibility in where those dollars are directed.

The programs “often include addressing STD disparities by race, ethnicity, or socioeconomic status,” said Jo Valentine, a health equity official in the CDC’s STD prevention branch.

African-Americans contracted syphilis at a far higher rate than other population groups, though African-Americans aren’t any more likely to take part in high-risk sexual behaviors than people of other races or ethnicities, Valentine said.

“A range of factors work to drive severe racial disparities and may put individuals at high risk for STDs,” she said.

Those factors: poverty, a lack of health insurance, and limited access to community resources. The disparities make it more difficult for some people to receive STD testing or treatment if they do contract syphilis, Valentine said, allowing the disease to spread more rapidly than it might in populations with better access to health care.

Those same factors that might be playing into the increase in syphilis cases among the entire US population, too, Valentine said.

Cases of syphilis grew more rapidly in Mississippi than in any other state, but health officials there say that the figures could be deceiving; cases in 2013 were underreported when the state health department switched over to a new operating system that year.

“We may have had some cases lost in translation in the conversion between systems,” said Nicholas G. Mosca of the Mississippi State Department of Health, noting that data showed similar changes in other STD rates that suggested those records were lost.