Some STDs are passed from a mother to her child before birth. The disease enters the baby's bloodstream during childbirth as the baby passes through the birth canal, or after birth if the mother nurses the baby and her breast milk is infected. Some viral STDs, especially AIDS, may be transmitted by blood contact such as open wounds, between people who share infected needles or received through a transfusion of infected blood. Some people believe that STDs can be transmitted through shaking hands or other contact. It is also thought it can be caught through contact with objects such as clothing or toilet seats. Such transmissions are extremely rare and highly unlikely. .
Chlamydia, caused by the Chlamydia trachoma's bacterium, is the most commonly transmitted STD in the United States. About 500,000 chlamydia infections are reported each year. But because chlamydia may not produce noticeable symptoms, it often goes undiagnosed. It is estimated that the true number of people infected with chlamydia is nearly ten times the number of reported cases. When symptoms develop, men may experience painful or burning urination or a discharge from the penis. Women may experience burning urination, vaginal secretion, or mild lower abdominal pain. If left untreated, chlamydia damages reproductive tissue, causing inflammation of the urethra in men and possibly (PID) in women. PID can cause chronic, debilitating pelvic pain, infertility, or fatal pregnancy complications. Chlamydia infections are diagnosed by testing penile and vaginal discharge for the presence of the bacteria. .
Gonorrhea, caused by the bacteria Neisseria gonorrhea, infects the membranes lining certain genital organs. Although roughly 325,000 gonorrhea infections are reported each year in the United States, experts estimate that closer to 800,000 people are infected annually. Like chlamydia, gonorrhea is often symptoms, and men are more likely to develop symptoms than women are.