Three decades ago, AIDS was an unknown disease. Now, 30 years after the first cases of the illness were documented, the Centers for Disease Control and Prevention has issued a new report about the disease’s spread and how often some at-risk communities get testing.
The report begins: "On June 5, 1981, MMWR published a report of Pneumocystis carinii pneumonia in five previously healthy young men in Los Angeles, California; two had died. This report later was acknowledged as the first published scientific account of what would become known as human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). Thirty years after that first report, the most recent estimate is that 33.3 million persons were living with HIV infection worldwide at the end of 2009."
The full report suggests that men who have sex with men may need HIV tests more often than once a year — perhaps as often as every three or six months, the CDC suggests.
About 1.2 million people in the U.S. were living with HIV in 2008, the CDC estimates, but about 20% don't know it. Here's a map of where HIV diagnoses are most common.