On 5 June 1981 a short report of five cases of pneumocystis pneumonia in young homosexual men in Los Angeles marked the discovery of AIDS, the first pandemic of the 20th century caused by a completely new virus, HIV.

On 5 June 1981 a short report of five cases of pneumocystis pneumonia in young homosexual men in Los Angeles marked the discovery of AIDS, the first pandemic of the 20th century caused by a completely new virus, HIV.