New numbers show a 28% jump in cases over two years. We break down what's behind these numbers.

If “syphilis” sounds to you like an illness people got in another century, you’re not alone. For decades, the infection was widely considered a disease of the past. But after years of decline, ...

Syphilis may still be contagious for a short time after treatment. People can take precautions to help avoid transmission before and after treatment. This can include avoiding sex for at least 1 week.

During its second stage, syphilis may lead to a rash on one or several parts of the body. It most commonly affects the trunk, palms of the hands, and soles of the feet. The rash typically does not ...

A 5,500-year-old skeleton from the Americas has yielded the oldest genetic evidence yet of a bacterium closely related to the ...