Intravenous drug abuse: use of contaminated needles.
Infected blood products through transfusion.
Perinatally by mother to infant.
Breast milk of infected women.
HIV, or human immunodeficiency virus, is a virus that can be transmitted through contact with infected blood or sexual fluids. The infected fluids or blood need to come into contact with mucus membranes or open wounds in order for the virus to get into a new host body.
Mother to Child
A pregnant mother who has HIV can transmit the virus to the fetus or baby. The infant can become infected in utero, during delivery or through feeding on infected breast milk. If the mother is infected, retro-viral therapy can start. Treatment may also include a C-section instead of vaginal birth and avoiding breast feeding. According to Planned Parenthood, without treatment 1 in 25 babies born to infected mothers will get HIV, with treatment only 1 in 100 babies will become infected.
This was a more common way to contract HIV in the 1970s and '80s. Since 1985 the United States has been testing for HIV in all donated blood, blood products and organs.