AIDS (acquired immune deficiency syndrome) was first recognized in North America in the early 1980s. It is caused by a virus known as HIV (human immunodeficiency virus). HIV infection has become a worldwide epidemic. The World Health Organization estimates that since its discovery, it has caused 36 million deaths worldwide. In 2013, approximately 35.3 million people were living with AIDS. In Canada, over 23,000 AIDS cases were recorded by The Public Health Agency of Canada between 1979 and 2014.
HIV is more common among certain populations at risk, such as bisexual and gay men and people who inject illicit drugs. The infection is also more common among socially disadvantaged communities.