The following was written by Lindsay Bosslet for Public Health Insider.

Public Health has documented a significant increase in syphilis cases in King County. We sat down with Dr. Lindley Barbee, the medical director of the Public Health – Seattle & King County STD Clinic to understand the latest figures and how to prevent the spread of this disease.

The HIV/STD program has documented an increase in the number of syphilis cases. What’s going on?

Syphilis cases are up all over the country, and in King County we are no different. Syphilis is typically more common among men who have sex with men, and part of the increase in syphilis may be changes in sexual behavior due to the expansion of PrEP (PrEP is HIV pre-exposure prophylaxis, a pill you can take every day to prevent HIV). Now we are starting to see it among-heterosexual men and women, and most concerning we are seeing cases in pregnant women as well. Pregnant women can pass syphilis to their unborn baby which can be devastating – including miscarriage, and still birth. This phenomenon is happening locally, but it is also being seen nationally, according to a recent STD surveillance report issued by the Centers for Disease Control and Prevention.

Does that mean almost everyone is at risk?

No. Syphilis is spread primarily through unprotected sex. In King County, most cases of syphilis occur in MSM, and Public Health recommends that all sexually active MSM test for syphilis at least once a year unless they are in long-term, mutually monogamous relationships. Among heterosexuals, the risk of syphilis remains low, but persons who are homeless, using meth, and/or exchanging sex for other commodities are at elevated risk and should test.

We particularly encourage women who engage in any of these activities to get tested if they are pregnant or think they may be pregnant. Syphilis can be passed along to babies, and it can cause lifelong effects if not treated early enough.

What is causing this spike? Why is it affecting a different group of people?

We don’t know just yet. We think that some of this increase may be related to PrEP use among MSM. The increase in PrEP use among MSM is a good thing since it prevents HIV, but the increase in all STDs – syphilis, gonorrhea and chlamydia – may be an unintended consequence. As for the increase among heterosexuals, we are not sure why this is happening, but we think this is related to drug use. We know that more heroin users are also using meth. This is bringing together different groups of people that didn’t used to interact, and some people experiencing chemical dependency and homelessness trade sex for drugs or other necessities. But the truth is, we just don’t know. While we are working to figure this out, our main goal is to help test and treat people before the disease becomes more widespread.

Is syphilis treatable?

Yes, but it’s best to catch it early. If caught early enough, it only takes one shot to treat. More advanced syphilis can require as many as three shots administered over the course of three weeks. Sometimes, syphilis infects the brain, eyes or hearing which can cause blindness, hearing loss, and strokes or other important health problems. Sometimes these symptoms resolve with treatment, but they can also be permanent. Early detection and treatment is key.

What are the signs of syphilis?

The tricky thing about syphilis is that it manifests itself in many different ways – and can easily go unnoticed. People might not notice the first sign of syphilis – a sore on their mouth, genitals or anus – because these sores rarely cause pain or discomfort and can be easily missed. Others experience pink, slightly raised rash that may be confused for other mild viral infections. A rash on the palms and soles is one classic presentation. If you have any of these symptoms – and particularly if you are a man who has sex with men, you should see a medical provider and get tested as soon as possible.

Does Public Health offer testing?

Yes. Those interested in getting tested can visit our STD clinic at Harborview Medical Center. Our services are confidential and offered on a sliding scale. No one will be turned away because of lack of payment. You can also ask for testing when receiving other medical services, just about anywhere.

I work with people experiencing homelessness or have contacts within the homeless communities in King County. How can I help?

When in doubt, recommend testing. Public Health has notified all area healthcare providers to test people experiencing homelessness and using methamphetamines as well as all women in their first trimester of pregnancy, and pregnant women at risk of syphilis again in their third trimester. The best thing you can do is to encourage anyone who may be at risk to seek testing and medical care.