HIV (human immunodeficiency virus) is a virus that attacks cells that help the body fight infection, making a person more vulnerable to other infections and diseases. It is spread by contact with certain bodily fluids of a person with HIV, most commonly during unprotected sex (sex without a condom or HIV medicine to prevent or treat HIV), or through sharing injection drug equipment. If left untreated, HIV can lead to the disease AIDS (acquired immunodeficiency syndrome). HIV is a lifelong condition, but treatments and certain strategies can prevent the virus from transmitting and the disease from progressing. HIV is found in body fluids such as blood, semen, vaginal fluids, and breast milk. It can be passed on through penetrative sex, oral sex, and sharing contaminated needles when injecting street drugs or in hospitals. It can also be transmitted from a mother to her baby during pregnancy, childbirth, or breastfeeding though many children escape infection. HIV cannot be passed on through kissing, coughing, mosquito bites, or touching.