There were five cases, all puzzling and all seeming to involve some defect or interruption of the immune system.

The doctor to whom the cases had been reported, a young assistant professor specializing in immunology at the University of California Los Angeles (UCLA), had asked his colleagues to watch for interesting "teaching cases" in the field of immunology, and he sensed something unusual in the illnesses of five gay men with chronic fevers, dramatic weight loss, swollen lymph nodes, diarrhea, and thrush, who were also found have a rare skin cancer known as Kaposi’s sarcoma, a rare form of pneumonia known as Pneumocystis carinii, and the DNA virus cytomegalovirus (CMV). All the patients appeared to have severely damaged immune systems.

Michael Gottlieb thought the cases sufficiently unusual to be reported to a professional journal, and he contacted the New England Journal of Medicine, which agreed that the cases should be publicized but told him that publication in the journal would take a minimum of three months. Meanwhile, they advised Gottlieb, he should submit a brief to the Morbidity and Mortality Weekly Report (MMWR), published by the Centers for Disease Control and Prevention.

So, in a terse announcement in the June 5, 1981, issue of MMWR, the world got its first official notice of a new disease, later to become known as HIV/AIDS, which the MMWR in a retrospective calls "perhaps the defining public health issue of our times."

This summer marks the 25^th anniversary of the publication of that initial report in 1981, and an estimated 40million people or more are now living with HIV infection worldwide, with 5 million of them infected during the year 2005 alone.

"The explosive trends in the global epidemic have also occurred in the United States," an editorial in the June 2006 issue of American Journal of Public Health points out. "An estimated 925,000 to 1,025,000 HIV-seropositive persons resided in the United States in 2003. Unless we find ways to field effective AIDS prevention and treatment programs on a global basis, we will continue to stand witness as a dangerous epidemic spins out of control, with tragic repercussions for the rest of this new century."

The American Journal of Public Health editorial notes some of the most important attributes of AIDS that are evident at the quarter-century milepost:

• AIDS emerges first in marginalized communities, where because of drug use patterns, alternative sexualities, gender, racial minority status, or lower socioeconomic status, sociocultural processes operate to create health disparities;
• AIDS is a disease of denial because of the stigmatizing aspects of the epidemic, making effective prevention and treatment responses more difficult;
• AIDS prevention works; meta-analyses of trials has shown that prevention models that directly target safe sexual practice or drug use have significant positive effects. Structural interventions such as testing the supply of transfused blood to eliminate HIV-infected plasma and the use of antiretroviral medications to interrupt vertical HIV transmission from mother to child are among successful prevention strategies.
• Biomedical responses may not be enough to end the epidemic. Vaccines, microbicides, and antiretroviral treatment have great appeal, but they may not be enough to overcome the potent socio-cultural forces that shape the epidemic.

Wondering how history will judge our actions so far, in the first quarter-century of the AIDS epidemic, the Journal editorial compares it to the way medieval Europeans combated the Black Plague. "Certainly future historians will have ample evidence that we recognized that AIDS was one of the great public health catastrophes of our time and that, whatever else motivated our responses, we were not ignorant of the dangers of the disease, of the means by which it was transmitted, of the groups that were at gravest risk of transmission, or of effective strategies to prevent further HIV transmission."

An editorial, "A Quarter Century of AIDS," and an article, "Michael Gottlieb and the Identification of AIDS," appear in the June 2006 issue of the American Journal of Public Health. Requests for reprints of the editorial should be addressed to rstall@pitt.edu. Reprints of the article are available from feee@mail.nih.gov.