Although there are several modes of transmission of HIV, the most common are through unprotected sex, sharing of needles and syringes, and transmission from mother to child during pregnancy, birth or breast feeding. Other less common modes of transmission include being bitten by an individual infected with HIV, eating food that is pre-chewed by an infected individual, being "stuck" with an infected object (generally in a health care setting) and contact with open wounds and mucous membranes of infected individuals. Blood transfusions, tissue and organ transplants, and tattoos and body piercings also increase the risk of HIV contraction.
The term AIDS is an abbreviation for acquired immune deficiency syndrome, the late stages of infection with the human immunodeficiency virus or HIV. After it infects the body, the HIV virus slowly destroys the immune system.