HIV-2 is a type of the human immunodeficiency virus that primarily affects the immune system, leading to AIDS if untreated. It is less common than HIV-1 and is mostly found in West Africa. Unlike HIV-1, HIV-2 generally progresses more slowly and may not lead to AIDS as quickly. It is transmitted through similar means, such as unprotected sex, sharing needles, and from mother to child during childbirth or breastfeeding. Early diagnosis and treatment can help manage the virus effectively.