The HIV virus primarily exists in the blood, semen, vaginal secretions, ascitic fluid, and bodily fluids of infected persons. There are three main transmission pathways: sexual contact, blood products, and mother-to-child transmission, which include homosexual, heterosexual, and bisexual contact; sharing needles for intravenous drug use, invasive medical procedures, tattooing, as well as transmission from an HIV-positive mother through placental delivery and breastfeeding. Normal activities such as handshaking, hugging, polite kissing, sharing meals, and living together do not transmit the HIV virus.