The human immunodeficiency virus (HIV) is transmitted through blood and body fluids and gradually breaks down the immune system usually over a three-to-15-year period leading to acquired immunodeficiency syndrome, or AIDS. Learn more about HIV/AIDS and Doctors Without Borders/Médecins Sans Frontières (MSF)'s response to the virus at http://www.msf.ca/en/hiv-aids 0:12 - What is HIV 0:23 - Transmission 0:34 - What kind of cells does HIV infect 0:55 - What are the impacts of HIV