HIV (human immunodeficiency virus) is a virus that attacks the immune system, making it difficult for the body to fight off infection and some diseases. Without treatment, HIV eventually causes AIDS (acquired immunodeficiency syndrome).

Initial HIV symptoms are similar to those of the flu and include fatigue, fever, weight loss, and swollen lymph nodes in the neck, armpits, or groin. Although there currently is no cure for HIV infection, a combination of medicines called highly active antiretroviral therapy, or HAART, helps prolong life for most people. With treatment, a person with HIV infection may live for many years without developing AIDS.