Introduction

Summary

The official birth date of the AIDS epidemic is 5 June 1981. In an article of fewer than 500 words published in the Centers for Disease Control’s (CDC) Morbidity and Mortality Weekly Report, American clinicians described a cluster of five cases of Pneumocystis carinii pneumonia, a very rare infection of the lungs hitherto seen only in patients with severely compromised immune systems. These five initial cases were diagnosed between October 1980 and May 1981. All were gay men living in Los Angeles who had previously been healthy and were not receiving drugs that suppressed the body’s immune response. Quite a strange coincidence.