The human immunodeficiency virus (HIV) is transmitted through blood and body fluids and gradually breaks down the immune system ­ usually over a threeto15year 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/hivaids

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