Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It typically progresses through four stages: primary, secondary, latent, and tertiary. Symptoms can vary, but early signs often include sores, rashes, and flu-like symptoms. If left untreated, syphilis can lead to serious health complications affecting the heart, brain, and other organs. The infection is primarily spread through sexual contact, but it can also be transmitted from an infected mother to her baby during pregnancy. Diagnosis is usually made through blood tests, and treatment typically involves antibiotics, such as penicillin. Early detection and treatment are crucial for preventing long-term health issues.