Is a sexually transmitted disease (STD) caused by Treponema pallidum bacteria. It is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the penis, scrotum, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. The bacteria are passed from the sore of an infected person to another person during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying. While many people infected with syphilis do not experience symptoms for years, they remain at risk if they are not treated. The primary stage of syphilis is usually marked by the appearance of a single sore (called a chancre), but there may be multiple sores. The time between infection with syphilis and the start of the first symptom can range from 10 to 90 days (average 21 days). The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body. The chancre lasts three to six weeks, and it heals without treatment. However, without adequate treatment, the infection moves to the secondary stage. Symptoms associated with the secondary stage include a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. The latent (hidden) stage of syphilis begins when primary and secondary symptoms disappear. Without treatment, the infected person will continue to have syphilis even though there are no signs or symptoms. This latent stage can last for years. Syphilis is treated with antibiotics.