National HIV Testing Day (NHTD) was originally established on June 27, 1995 to promote testing for HIV. Annual observation will take place once again on June 27. In the hopes of inspiring you to get tested, a brief review of the origins and history of the virus follows.


In an article published in Retrovirology, Dr. Robert Gallo, credited as co-discoverer of HIV, outlines the World Health Organization's (WHO) history of the disease:

  • Silent spread (date ?-1981)
  • Recognition (1981-1982)
  • Intense discovery (1982-1985)
  • Global mobilization (1986-1988)
  • Ending the problem by blood testing (1984), public education (1986), anti-viral treatment (1986), and development of a vaccine (date ?)

The primate-to-man origin of HIV had been suspected nearly from the earliest days of awareness, though which primate was unknown. People in rainforests (in particular, hunters), Gallo suspects, were occasionally infected for a long time but then they died with their disease. The transference of the virus from rainforests to the wider world is seen, from Gallo's perspective, as a consequence of post-World War II changes: increased travel (and increased promiscuity), mounting intravenous drug addiction, and blood and blood products moving from one nation to another for medical purposes.

Although originally researchers proposed the 1970s as the years of "silent spread" of the disease, Gallo and other scientists believe that process began much earlier. Outside of sub-Saharan Africa, Haiti appears to have the oldest HIV/AIDS epidemic; using gene sequences recovered from archival samples of the earliest known Haitian AIDS patients, researchers believe that subtype B of the virus likely moved from Africa to Haiti in or around 1966 and spread there before dispersing elsewhere. Most probably, then, the virus had been in Africa for years before that date.

Despite the unknown date of origin, identification of the disease by clinicians is clear.


In 1981, U.S. clinicians defined the disease as an immune disorder they labeled 'acquired immunodeficiency syndrome' (AIDS) and the following year, they had identified risk groups, called the 4 H's: hemophiliacs, heroin addicts, homosexuals, and Haitians. Gallo and his colleagues initiated their experimentation in May 1982 that led to discovery of human immunodeficiency virus (HIV). "At the time, there were at least a dozen theories as to the cause of AIDS, including non-infectious causes," wrote Gallo. He speculated that AIDS would be caused by a retrovirus in the HTLV (Human T-cell Lymphotropic virus, which causes a type of leukemia) family and soon learned his theory was only partially correct; HIV was indeed a retrovirus, but separate from HTLV.

A period of intense discovery during the years 1983-85 quickly followed isolation of HIV. Demonstrating that HIV was the cause of AIDS offered surprising challenges, most especially due to the long period between infection and signs of disease (five to 15 years). "Physicians and public health officials do not ask a patient what they did a decade earlier, but rather think in terms of days or weeks," wrote Gallo. The numerous infections a patient develops as they present with AIDS was a second hurtle, as scientists didn't understand which, if any, caused the virus.

Described by Jonathan Mann of WHO as "the fastest pace of discovery in medical history," the many noteworthy advances included: discovery of HIV (1983-84); convincing evidence HIV was the cause of AIDS (1984); modes of transmission understood (1984-85); genome sequenced (1985); most genes and proteins defined (1984-'85); main target cells -- CD4 T cells, macrophages, and brain microglial cells -- elucidated; key reagents produced and made available for scientists worldwide (1984-'85); genomic heterogeneity of HIV (1984); first practical life saving advance (1985); the blood test (1984); close monitoring of the epidemic due to wide availability of the blood test (1985); the SIV-monkey model (1985); the beginning of therapy - AZT (1985); and initial understanding of pathogenesis (1985).

After these heady days of early discovery, scientists organized a worldwide attack.

Mobilization and Beyond

Key within the period of global mobilization was education to prevent infection, a practical advance that continues today. "There is proven success in some places, but not all, and sometimes there is only temporary success," wrote Gallo. Among the advances occurring since 1986, none were more important, Gallo suggests, than therapy. AZT showed that a viral disease could be treated, resulting in a decline in virus levels and weakened signs of AIDS. All treatments thereafter were built on this fresh understanding of the disease and came about through contributions from a number of scientists, including those who studied HIV replication, those who developed the culture systems, and those who worked in the pharmaceutical industry.

In many cases, practical advances since 1986 have extended earlier ones: more widespread use of testing and educational programs; refined therapies; greater knowledge about HIV drug resistance and how to avoid it; better care of patients; and learning about serious co-infections especially of tuberculosis and hepatitis C.


Although the first identified cases were in MSM (men who have sex with men) in the U.S. and western Europe, the greatest impact of the epidemic has been in sub-Saharan Africa, where most transmission occurs between heterosexuals. Today, the nine countries in southern Africa that account for less than two percent of the world's population represent about one third of global HIV infections. Although HIV screening, access to sterile equipment by IV drug users, and antiretroviral treatment of pregnant women have been highly effective (when broadly implemented), prevention has been difficult. Many believe the greatest challenge remains the global community of MSM in which HIV remains endemic at high prevalence.

Gallo ends his reflections by drawing attention to the "silver lining on the dark AIDS clouds." He notes the many positive spin-offs in immunology, cancer biology, basic virology, and molecular biology; he remarks upon the focus AIDS research has provided to therapy of viral infections and to vaccine development. "Consider how AIDS has inspired far greater tolerance (at least in the West) of differences in sexuality and much greater scientific and humanitarian collaborations between developed and less developed nations," he wrote. One smaller achievement is the change in various policies at the Food and Drug Administration (FDA).

ACT UP and Iris Long

AIDS Coalition to Unleash Power (ACT UP) describes itself as a "diverse, non-partisan group of individuals united in anger and committed to direct action to end the AIDS crisis." Formed in 1987 at the Lesbian and Gay Community Services Center in New York, their motto soon became "Silence = Death." This group was largely responsible for transforming the FDA.

Iris Long was among those in ACT UP who became involved with the FDA. Having received her Ph.D. from the Department of Pharmacy at the University of Connecticut and having worked at Sloan-Kettering, Long had naturally became interested and decided to volunteer when the AIDS epidemic began. Although she had worked with other groups, she found a home at ACT UP, where co-founder Larry Kramer welcomed her knowledge and experience.

Essentially, Long helped the organization understand the need to inspire the FDA to test more drugs. Her experience with her dying mother had shown Long the necessity to become a fierce advocate for those who are sick. "I knew at that time in my life that if you want drugs, you're going to have to fight for these things," she explained in an interview. "You're going to have to fight whatever bureaucracy is there. I didn't really understand the whole bureaucracy thing completely - with doctors and institutions - the grants and things like that...but I knew ... this is something you had to know about."

With Long's direction, then, ACT UP began to study, protest, and recommend new policies and practices to the FDA. One of these was "compassionate use," in which the FDA allows companies to provide their experimental drugs to people with life-threatening diseases outside of clinical trials. Another change instigated by ACT UP and Long was 'parallel tracking;' the FDA established a 'parallel' administrative system to expand the availability of drugs beyond controlled clinical trials. In a controlled trial, patients are chosen because they have not previously been treated with other medications. With the more inclusive parallel system, the so called "dirty" results from trials with previously treated patients expanded scientists' understanding of experimental drugs and contributed to a creation of 'drug cocktails' as treatment.

Sources: Gallo RC. A reflection on HIV/AIDS research after 25 years. Retrovirology 2006.

Gilbert MT, Rambaut A, Wlasiuk G, Spira TJ, Pitchenik AE, Worobey M. The emergence of HIV/AIDS in the Americas and beyond. PNAS. 2007.

Sharp PM, Hahn BH. Origins of HIV and the AIDS pandemic. Cold Spring Harb Perspect Med. 2011.

Schulman S. ACT UP Oral History Project. The New York Lesbian & Gay Experimental Film Festival, Inc. 2004.