Syphilis :
Syphilis is a sexually transmitted infection that is caused by bacteria. It develops when an individual has any sexual contact with someone who is infected with this disease. This infection progresses in four stages. First, a hard lump appears on the anus, genitals or mouth. The lump disappears in a few months and rashes appear on the body in the second stage. In the third stage, the bacteria continue to live in the body and it may not show any outward signs. In the final stage, the infection causes serious problems like heart problems, blindness and brain damage. The infection can be diagnosed with a blood test. If it's in the first stage, then the fluid or skin from the sore may be viewed under a microscope to provide a diagnosis. It can be cured by taking antibiotics.