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Special Reviews

The evolving epidemiology of HIV/AIDS

De Cock, Kevin M.a; Jaffe, Harold W.a; Curran, James W.b

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doi: 10.1097/QAD.0b013e328354622a



With regret, references [87,88] in the article, ‘The evolving epidemiology of HIV/AIDS’ by De Cock et al. are listed, incorrectly. The correct references are:

87. Cohen J. An unsafe practice turned blood donors into victims. Science 2004; 304:1438–1439.

88. Mastro TD, Yip R. The legacy of unhygienic plasma collection in China. AIDS 2006; 20:1451–1452.

AIDS. 26(13):1733, August 24, 2012.


In this review, we describe the epidemiology of the HIV/AIDS epidemic, both chronologically and by HIV transmission route, and highlight prevention interventions and other factors potentially affecting transmission and spread. We first discuss recognition of the epidemic, discovery of HIV transmission routes, and initial prevention efforts during the early to mid-1980s. We then examine how the epidemic and prevention approaches evolved during the pre-antiretroviral therapy (ART) era, and conclude by describing the current epidemic and prospects for control. In an earlier publication, we have discussed the broader implications of the world's three decades of experience with HIV/AIDS [1].

A medical mystery

What became known as AIDS was first described in a report published on 5 June 1981. Gottlieb and colleagues reported five young, previously healthy, homosexual men treated for Pneumocystis carinii (now Pneumocystis jiroveci) pneumonia (PCP) in three Los Angeles hospitals [2]. Those tested had evidence of T-lymphocyte depletion, and two had died. Over the following months, additional cases of PCP, other opportunistic infections, and Kaposi's sarcoma among MSM were reported from several US cities. Although the cause of the immunodeficiency was unknown, cases in sex partners [3] along with the results of a national case–control study [4] strongly suggested a sexually transmitted infection.

By January 1983, the major transmission routes of the still unidentified ‘AIDS agent’ had been described. Heterosexual transmission was indicated by reports of similar immunodeficiency in female sex partners of men with AIDS in New York [5]. Unexplained immunodeficiency and opportunistic infections in infants born to mothers with AIDS-related illnesses pointed to mother-to-child transmission [6]. Several lines of evidence indicated transmission through blood and blood products, including cases in injection drug users (IDUs) and persons with hemophilia. Moreover, the development of the disease in an infant in San Francisco following receipt of a platelet transfusion from a donor with subsequent PCP was reported [7–9]. Later cases in healthcare workers (HCWs) with occupational exposure to blood were also consistent with blood-borne transmission [10].

By February 1983, the Centers for Disease Control (CDC) had received reports of 1000 persons with AIDS in the United States; mortality had been 39% [11]. Almost all were MSM, IDUs, persons with hemophilia, or, perplexingly, recent immigrants from Haiti with undetermined risk factors. Seventy-two percent of affected MSM were non-Hispanic whites; in contrast, about three-quarters of affected IDUs were blacks or Hispanics. The report of the first thousand cases concluded that trends suggested ‘gradual extension of an infectious agent into new populations’.

Although HIV had not yet been identified, the US Public Health Service issued the first recommendations for AIDS prevention in March 1983 [12]. The report noted that having multiple sex partners increased the risk of AIDS and recommended that members of groups at increased risk refrain from donating plasma and/or blood. Later that year, the causative agent was identified [13], and in 1985, antibody testing became available [14]; this test enabled further prevention measures such as deferral of seropositive persons from plasma and blood donation and heat treatment of clotting factor preparations to inactivate the virus. Guidelines were issued for HCWs to avoid occupational exposure to blood and for IDUs to avoid sharing needles and other injection equipment. Infected mothers were advised to consider delaying pregnancy until more was known about the risk to the infant [15].

Little was known at that time about HIV/AIDS outside of the United States. After AIDS had been diagnosed in Haitians recently entering the United States, cases were described in Haiti. Although initial reports of these cases suggested male bisexual activity and blood transfusion as important risk factors [16], follow-up studies indicated heterosexual transmission as the predominant mode of spread [17]. Elsewhere, member countries of the WHO European Region had reported 267 cases through October 1983 [18], including cases among Africans seeking care [19]. Initial studies in Africa revealed large numbers of cases in heterosexual patients in central African cities such as Kinshasa, Zaire (now the Democratic Republic of Congo), and Kigali, Rwanda [20,21].

Although HIV transmission routes had been established, some feared transmission through insect bites or ‘casual’ contact with infected persons. These fears persisted until studies from south Florida found no correlation between HIV infection and mosquito exposure [22] and studies from the Bronx, New York, found no casual transmission between AIDS patients and their family members [23].

An evolving epidemic

Over the next decade, perceptions of HIV/AIDS evolved from a medical quandary primarily affecting MSM in the United States to a pandemic of uncertain magnitude threatening diverse populations around the world. The pandemic was not one phenomenon but a patchwork of epidemics moving through different groups and countries at different times. They were characterized by waves of unapparent HIV infections followed by visible epidemics of disease and death. Peak HIV prevalence was useful as an indicator to compare the severity of epidemics between locations and over time [24].

Molecular epidemiologic studies have provided insights into the origin and broad geographic transmission patterns of HIV-1 [25]. The virus is thought to have entered human populations in the early twentieth century through cross-species transmission of related chimpanzee retroviruses found in western equatorial Africa [26,27]. By the early 1980s, multiple genetic subtypes of HIV-1 were present in Kinshasa, Zaire [28]. Examination of genetic sequences of HIV-1 recovered from early Haitian patients suggested spread of HIV-1 infection from Africa to Haiti in the 1960s and later introduction to the United States [29], although multiple introductions were likely.

By the mid-1990s, more than 20 million persons were estimated to be living with HIV/AIDS, the vast majority in sub-Saharan Africa [30]. Largely reflecting the African epidemic, sexual transmission accounted for at least three quarters of all new infections, most in heterosexuals. Overall, women accounted for about 40% of infected adults. With exceptions of sub-Saharan Africa and Haiti, however, fears of a ‘generalized,’ self-sustaining, heterosexual epidemic throughout the world did not materialize. In retrospect, lack of generalized heterosexual spread in the large populations of Asia was one of the most important observations for understanding global HIV/AIDS epidemiology [31]. In the United States, MSM continued to account for the majority of cases [32]. Male-to-male transmission also predominated in western Europe, particularly in northern countries, in Australia and New Zealand, and in parts of Latin America [30,33]. The HIV/AIDS burden in western Europe, however, was also heavily affected by immigration from Africa, whereas southern Europe had relatively more IDU-associated HIV/AIDS.

Using a back-calculation method, Brookmeyer [34] reconstructed the AIDS epidemic in the United States and concluded that HIV incidence in MSM had peaked in the mid-1980s and then rapidly decreased. Substantial behavioral change among MSM contributed to early incidence declines [35,36], but high mortality among men most likely to transmit HIV must also have played a role. Further, the falling incidence predated substantial government funding for HIV prevention and likely reflected prevention efforts within the MSM community itself. Prevention guidelines for MSM emphasized the need for HIV testing, informing partners of infection status, and safe sex practices [15].

Early efforts to assess the burden of disease in Africa and elsewhere were based on reporting of AIDS cases to WHO using clinical case definitions [37]. Despite incomplete diagnosis and reporting, these efforts usefully documented the occurrence of AIDS in specific countries and extension globally. Once serologic testing for HIV became available, the extent of HIV spread along with its risk factors and modes of transmission were studied systematically. Sentinel surveillance for HIV infection was initiated in pregnant women, who by definition were sexually active, relatively representative of the general population, and comparable between locations. This approach has remained an important basis for estimating HIV incidence and prevalence throughout the world [38,39], although such estimates have remained controversial [40–42]. But, despite providing important insights into populations at risk and epidemic trends [43,44], the practice of unlinked anonymous testing, especially the inclusion of pregnant women, has been questioned [45].

Silent spread of HIV from Central Africa began in the late 1970s, and by the early-to-mid 1980s, when AIDS was becoming apparent in Kenya, the majority of female sex workers in Nairobi were already infected [46,47]. Although ascertainment and reporting biases may affect our understanding, spread to countries of western Africa occurred later in the 1980s [48,49], with extension to southern Africa most intense from the 1990s onward. Studies in urban centers across the continent showed especially high rates of HIV infection in female sex workers and other persons with high numbers of partners [46,47,50].

In the African epidemic, genital ulcer disease, particularly chancroid, was a strong co-factor for HIV infection [51,52]. Other, nonulcerative, infections such as gonorrhea also appeared to increase transmissibility by increasing HIV shedding [53]. As chancroid became less common in many locations, herpes simplex type 2 (HSV-2) emerged as the predominant cause of genital ulcer disease associated with HIV [54]. Ecologic studies also demonstrated that African countries with low male circumcision rates (southern and, to a lesser extent, eastern Africa) generally had high HIV infection rates and vice versa (highly circumcised west African populations were less heavily infected with HIV) [55]. These studies and analytic observations [51,52] provided evidence that lack of circumcision increased the risk for males acquiring HIV infection and prompted later research that culminated in intervention trials and subsequent programmatic implementation.

An additional complexity in the African epidemic was a second AIDS virus, HIV-2, first reported from west Africa in 1986 [56]. Like HIV-1, this virus is thought to have entered human populations through cross-species transmission: a highly related retrovirus is present in sooty mangabeys in this geographic area [26,27]. HIV-2 is transmitted through sexual contact and blood, but very rarely from mother to child [57]. Although the virus causes AIDS, it has a slower rate of disease progression than HIV-1 [58–60] and is overall less transmissible [61].

Initial prevention efforts in sub-Saharan Africa concentrated on limiting heterosexual transmission through the ‘ABC’ strategy: abstain, be faithful, and use condoms, a message communicated in culturally meaningful or colorful phrases such as ‘zero grazing’ and ‘condomize’ ([62], this issue). The fall in HIV prevalence in childbearing women in Uganda during the early 1990s has been attributed to this approach, although this interpretation is controversial [63,64]. But, as in the United States, massive numbers of deaths of potential HIV transmitters must have influenced epidemiology. A more clear-cut prevention success was Thailand's ‘100% condom campaign’, which targeted female sex workers and their clients [31,65,66]. Another early, oft-cited ‘prevention success’ occurred in Senegal, where HIV/AIDS never spread widely [65]. Senegal was exemplary in its openness and political commitment. However, the predominance of HIV-2, concentration of HIV-1 in high-risk groups, universal nature of male circumcision, and traditional and religious cultures in the country may have been more powerful factors than specific HIV prevention campaigns.

In the late 1980s, studies in the former Zaire showed a 21% risk of HIV transmission from an infected mother to her infant in the perinatal period [67]. Prolonged breast feeding, the norm in sub-Saharan Africa for cultural and socio-economic reasons, increased transmission by an additional 14% [68], resulting in an overall transmission risk of 30–45% [69]. These breastfeeding findings caused difficult policy choices between advocating replacement feeding, associated with the risk of malnutrition, diarrhea, and respiratory disease, and continued breastfeeding, which increased the risk of HIV infection [69–71]. Not until the advent of interventions based on antiretroviral therapy (ART) could this conundrum begin to be addressed [72–74], ([75], this issue).

The global epidemic evolved somewhat differently in IDUs than in MSM. Most affected were IDUs in southern Europe, parts of south and south-east Asia, and countries of the former Soviet Union. For example, HIV prevalence among IDUs living in one Ukrainian city rose from less than 2% to more than 50% in less than a year [30]. The US Institute of Medicine concluded that treating drug dependence, including the use of opioid agonist medications, was the preferred risk reduction approach for IDUs. However, the provision of clean injecting equipment was an effective intervention when treatment was not available or accessible [76]. Unfortunately, the use of funds from the US government, the largest funder of HIV/AIDS programs globally, was prohibited for needle and syringe exchange.

Whereas donor deferral and HIV screening of blood almost eliminated transfusion-acquired HIV in industrialized countries, the risk remained in many developing countries. Contributing factors included lack of infrastructure for blood collection, storage, and HIV testing; use of paid or family members as donors; lack of high-risk donor exclusion; high rates of unnecessary transfusions; and increased transfusion needs by pregnant women and children because of malarial anemia [77,78]. Nonetheless, through WHO and donor leadership in prioritizing national blood transfusion services, numerous HIV infections were averted each year in sub-Saharan Africa [79]. Further, the consensus belief that any transmission of HIV by blood transfusion was unacceptable helped prioritize prevention of this mode of transmission.

Additional studies in health care settings showed that the risk of infection in HCWs exposed percutaneously to HIV-infected blood, most often through a needle stick, was approximately 0.3%. This risk was shown to be reduced by about 80% with the use of zidovudine as postexposure prophylaxis [80]. Another transmission risk in healthcare settings was reported in a CDC investigation of an HIV-infected dentist in Florida who transmitted the infection to five of his patients [81]. Although the specific route of transmission could not be determined, subsequent guidelines established procedures for restricting the practices of infected HCWs who performed certain invasive procedures [82]. Extensive HIV transmission occurred in the late 1980s among abandoned Romanian children living in chronic care hospitals and orphanages; only 10% of mothers of infected children were themselves HIV-infected and most children were thought to have contracted HIV from injections with contaminated needles and syringes or blood transfusions [83,84]. An outbreak of nosocomial infection was also documented in Benghazi, Libya, affecting almost 400 children [85]. Despite the occurrence of such tragic events, they were not major contributors to pandemic spread [86].

A number of outbreaks of HIV infection have been recognized among blood or plasma donors in whom attention to sterility of equipment and to overall blood safety was inadequate. The most devastating experience was in China where up to 250 000 predominantly rural villagers across five provinces may have been infected with HIV through the commercial blood trade in the early 1990s [87,88]. Commercial blood and plasma donation was extensive in this region and hygienic practices were inadequate, such as pooling of cell fractions and return to donors after plasma separation. Although these practices were corrected in the mid-1990s, high rates of disease and death were documented a decade later [87,88].

A defining event, 15 years after AIDS was first described, were reports at the International Conference on AIDS in Vancouver in 1996 of lowering of viral load and delayed progression of HIV disease in persons taking combination ART [87]. The advent of effective therapy for HIV disease meant that AIDS case surveillance no longer gave unbiased insight into earlier trends in HIV transmission but henceforth was influenced by late diagnosis, inadequate access to care, failure of adherence to medications, or drug resistance. In response, CDC shifted emphasis onto the reporting of HIV diagnoses for surveillance purposes [88].

Now and the future

Three decades after the first description of AIDS, an estimated 34.0 million (uncertainty range 31.6–35.2 million) people were living with HIV, 2.7 million (uncertainty range 2.4–2.9 million) had become newly infected with HIV over the previous year, including 390 000 children, and 1.8 million (uncertainty range 1.6–1.9 million) HIV-infected persons died [89]. More than two-thirds of HIV infections, roughly 22.9 million persons, were in sub-Saharan Africa, which also accounted for close to 80% of women and 90% of children living with HIV. South and south-east Asia were home to some 4.0 million HIV-infected persons, and the Americas, including the Caribbean, to about 3.0 million. Although HIV/AIDS has caused appalling mortality in MSM and IDUs, the experience of sub-Saharan Africa has made HIV/AIDS the greatest challenge to global health in modern times. Moreover, there has been a severe secondary epidemic of HIV-associated tuberculosis, with an estimated 350 000 deaths among the 1 100 000 persons affected by both infections in 2010 [90].

In stark contrast to early observations from central Africa, southern Africa is now firmly established as the global HIV/AIDS epicenter: nine countries in southern Africa account for less than 2% of the world's population, but represent about one-third of global HIV infections and almost half of the world's HIV-associated tuberculosis. Lack of male circumcision and high rates of HSV-2 infection are frequently cited factors associated with high HIV prevalence [91]. The suggested role of concurrent sex partners [92] and putative viral subtype-specific differences in transmissibility is controversial. Urbanization and population movement along with the sociopolitical changes that have occurred over the past two decades have also likely contributed to the southern African epidemic.

Globally, HIV incidence probably peaked around 1997 [89]. In many countries such as the United States, however, incidence has remained relatively stable for over a decade [93], and without additional prevention efforts, the burden of HIV/AIDS continues. Determinants of current and future HIV/AIDS epidemiology include the natural history of regional and local epidemics themselves, social and behavioral trends, and the effects of public health and medical interventions. To what extent HIV/AIDS epidemiology in Africa could have been mitigated by early emphasis on proven public health measures and focus on groups at highest risk, especially sex workers and their clients, remains for discussion [94,95].

As we enter the fourth decade of the pandemic, biomedical approaches to prevention are emerging as more promising than current mass communication and behavioral interventions. Randomized clinical trials have provided strong evidence for the use of antiretroviral drugs, both as treatment and as preexposure prophylaxis, for preventing sexual transmission of HIV ([62,75], this issue). In particular, the high prevention impact of treatment among discordant couples in the HPTN 052 study [96], combined with ecologic evidence [97] and results of mathematical modeling [98], suggest that early and widespread initiation of ART in people with HIV could substantially reduce sexual transmission in generalized HIV epidemics in sub-Saharan Africa, as well as the incidence of HIV-associated tuberculosis [99]. Randomized clinical trial data from sub-Saharan Africa also provided strong evidence that male circumcision partially prevents female-to-male sexual transmission [100–102], and led to policy guidance [103]. Despite tremendous progress [104] and huge prevention potential [105,106], the extent to which these interventions can be brought to scale remains uncertain [107], as does their current population-level impact. For example, even in the United States, only 28% of HIV-infected persons are estimated to be on treatment and have suppressed viral loads [108].

Prevention of mother-to-child transmission has seen a step-wise introduction of evidence-based interventions, with impressive impact in industrialized countries ([62], this issue). In the United States, for example, near-universal testing of pregnant women, provision of appropriate antiretroviral treatment or prophylaxis, and avoidance of breastfeeding by HIV-infected mothers have virtually eliminated new pediatric HIV infections [109]. The concern that the findings of the ACTG 076 study [110], which showed the benefits of zidovudine monotherapy, could not be implemented in Africa led to the search for simpler regimens. The HIVNET 012 study [111], which used single-dose nevirapine, was initially greeted with enthusiasm because of the simplicity, low cost, and relatively high efficacy of the regimen (about 50%). Unfortunately, challenges to program adherence, transmission through breastfeeding, and recognition that monotherapy was a risk factor for later drug resistance all became apparent, and single-dose nevirapine is now considered a suboptimal approach.

The most important intervention for preventing mother-to-child transmission of HIV is to identify and treat pregnant women who need ART for their own health, currently defined as those with CD4+ cell counts less than 350 cells/μl [112]. Discussion continues about approaches that could replace WHO's complex current recommendations for pregnant women and infants [113], but a pragmatic approach being considered by some countries (e.g., Malawi) would be to provide immediate and lifelong combination ART for all HIV-infected pregnant women irrespective of CD4+ cell count.

United Nations Agencies have set a goal of reducing new pediatric HIV infections from the 2009 baseline of approximately 400 000 infections to less than 40 000 infections by 2015, a 90% reduction [114]. Currently, available interventions can lower mother-to-child transmission rates in breastfeeding populations to less than 5%, and success will require much more aggressive uptake of HIV testing and provision of ART. Linkage of these interventions to other efforts to improve maternal and child health, including safe delivery in health facilities, will be essential, especially in Africa.

Globally, about 3 million IDUs are estimated to be infected with HIV, and drug injection accounts for almost one-third of HIV incidence outside of sub-Saharan Africa. The greatest number of HIV-infected IDUs resides in eastern Europe and south-east Asia [89], where their access to services is limited because of stigma, discrimination, and the definition of drug dependence as a law enforcement rather than public health issue. Along with HIV, IDUs suffer high rates of hepatitis B and C infections as well as tuberculosis, and can be an important source of sexual transmission of HIV. Experience in other parts of the world where HIV has been successfully controlled in IDUs illustrates that currently available interventions can be effective [115]. Ecologic evidence also suggests that expansion of ART among HIV-infected drug injectors has a prevention benefit [97].

Perhaps the greatest challenge is among MSM, in whom there is little evidence of sustained prevention success [116]. HIV has become endemic in MSM populations in the industrialized world; annual HIV incidence rates around 2–3% are common, as are prevalence rates of 10–30%. In the United States, HIV incidence in young MSM, especially young black MSM, continues to increase [92]. In a venue-based study in 21 American cities, 24% of black MSM aged 20–29 years were HIV-positive; most were unaware of their infection [117].

While largely overlooked earlier in the epidemic, recent studies have documented populations of MSM in low- and middle-income countries, including in Africa [118]. When HIV epidemiology is studied in these groups, high rates of infection are invariably found, typically higher than those in the general population. Using the Incidence by Mode of Transmission Model, UNAIDS and The World Bank have estimated that MSM may account for 7.5%–14% of all new HIV infections in Nigeria, for example [119]. Studies in these countries often document extreme stigma, discrimination, and human rights abuses toward people who practice same-sex behavior – factors preventing openness and active HIV prevention. Even in more tolerant societies, however, such as in western Europe, prevention efforts are generally failing to reduce HIV incidence in men.


Although heterosexual transmission remains the dominant mode of spread worldwide, we have witnessed encouraging trends in Africa's generalized epidemics [120,121], evidence of efficacy of biomedical interventions (especially ART-based prevention and male circumcision) [122], and successful prevention program scale-up [104]. ART-based prevention approaches have the potential to reduce all modes of transmission ([75], this issue). Cautious optimism is justified when this reality and the tools available are contrasted to the history of the pre-ART era. However, continued funding, intensified program implementation, massive scale-up of HIV testing, surveillance, and appropriate intervention and implementation science are critical to success.

Much more can be done to prevent and treat HIV infection in IDUs and sex workers, whose needs remain neglected and for whom targeted services can substantially reduce HIV transmission. Mother-to-child transmission of HIV is largely preventable, trends are encouraging, and the world's attention is now focused on this problem. Although continued efforts are needed to improve blood safety [123] and reduce healthcare-associated infections, blood transfusion and medical injections are not major modes of HIV transmission. Strikingly, HIV among MSM, the issue that first brought AIDS to attention, remains largely refractory to current interventions in all countries of the world. Because of treatment advances, HIV prevention may seem less important to MSM in high-income settings today than in earlier decades. In low-income and middle-income countries, however, HIV/AIDS in MSM is just beginning to be addressed. Without changes in attitudes of society as a whole and greater behavioral change by MSM themselves, HIV will remain highly endemic throughout the global community of MSM for the foreseeable future.

Collectively, we are at a pivotal moment in the HIV/AIDS epidemic. We now have the tools to change the course of the global epidemic. Whether we have the resources and political will to use those tools remains to be determined. It will be for future generations to judge whether we did all that we could.


Conflicts of interest

There are no conflicts of interest.


1. De Cock KM, Jaffe HW, Curran JW. Reflections on 30 years of AIDS. Emerg Infect Dis 2011; 17:1044–1048.
2. Centers for Disease Control. Pneumocystis Pneumonia – Los Angeles. MMWR 1981; 30:250–252.
3. Centers for Disease Control. A cluster of Kaposi's sarcoma and Pneumocystis carinii pneumonia cases among homosexual male residents of Los Angeles and Orange Counties, California. MMWR 1982; 31:305–307.
4. Jaffe HW, Choi K, Thomas PA, Haverkos HW, Auerbach DM, Guinan ME, et al. National case–control study of Kaposi's sarcoma and Pneumocystis carinii pneumonia in homosexual men. Part 1: Epidemiologic results. Ann Intern Med 1983; 99:145–151.
5. Centers for Disease Control. Immunodeficiency among female sexual partners of males with acquired immune deficiency syndrome (AIDS) – New York. MMWR 1983; 31:697–698.
6. Centers for Disease Control. Unexplained immunodeficiency and opportunistic infections in infants – New York, New Jersey, California. MMWR 1982; 31:665–667.
7. Centers for Disease Control. Update on Kaposi's sarcoma and opportunistic infections in previously healthy persons – United States. MMWR 1982; 31:294–301.
8. Centers for Disease Control. Pneumocystis carinii pneumonia among persons with hemophilia A. MMWR 1982; 31:365–367.
9. Centers for Disease Control. Possible transfusion-associated acquired immune deficiency syndrome (AIDS) – California. MMWR 1982; 31:652–654.
10. Anonymous. Needlestick transmission of HTLV-III from a patient infected in Africa. Lancet 1984; 324:1376–1377.
11. Jaffe HW, Bregman DJ, Selik RM. Acquired immune deficiency syndrome in the United States: The first 1,000 cases. J Infect Dis 1983; 148:339–345.
12. Centers for Disease Control. Prevention of acquired immune deficiency syndrome (AIDS): report of inter-agency recommendations. MMWR 1983; 32:101–104.
13. Barré-Sinoussi F, Chermann JC, Rey F, Nugeyre MT, Chamaret S, Gruest J, et al. Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS). Science 1983; 220:868–871.
14. Centers for Disease Control. Provisional Public Health Service inter-agency recommendations for screening donated blood and plasma for antibody to the virus causing acquired immunodeficiency syndrome. MMWR 1985; 34:1–5.
15. Centers for Disease Control. Additional recommendations to reduce sexual and drug abuse-related transmission of human T-lymphotropic virus type III/lymphadenopathy-associated virus. MMWR 1986; 35:152–155.
16. Pape JW, Liautaud B, Thomas F, Mathurin J-R, St Amand M-MA, Boncy M, et al.Characteristics of the acquired immunodeficiency syndrome (AIDS) in Haiti. N Engl J Med 1983; 309:945–950.
17. Pape JW, Liautaud B, Thomas F, Mathurin J-R, St Amand M-MA, Boncy M, et al.The acquired immunodeficiency syndrome in Haiti. Ann Intern Med 1985; 103:674–678.
18. Centers for Disease Control. Acquired immunodeficiency syndrome (AIDS) – Europe. MMWR 1983; 32:610–611.
19. Clumeck N, Sonnet J, Taelman H, Mascart-Lemone F, De Bruyere M, Vandeperre P, et al. Acquired immunodeficiency syndrome in African patients. N Engl J Med 1984; 310:492–497.
20. Piot P, Taelman H, Bila Minlangu K, Mbendi N, Ndangi K, Kalambayi K, et al. Acquired immunodeficiency syndrome in a heterosexual population in Zaire. Lancet 1984; 324:65–69.
21. Van De Perre P, Lepage P, Kestelyn P, Hekker A, Rouvroy D, Bongaerts J, et al. Acquired immunodeficiency syndrome in Rwanda. Lancet 1984; 324:62–65.
22. Castro KG, Lieb S, Jaffe HW, Narkunas JP, Calisher CH, Bush TJ, et al. Transmission of HIV in Belle Glade, Florida: lessons for other communities in the United States. Science 1988; 239:193–197.
23. Friedland GH, Saltzman BR, Rogers MF, Kahl PA, Lesser ML, Mayers MM, et al. Lack of transmission of HTLV-III/LAV infection to household contacts of patients with AIDS or AIDS-related complex with oral candidiasis. N Engl J Med 1986; 314:344–349.
24. Hargrove J. Migration, mines and mores: the HIV epidemic in southern Africa. S Afr J Sci 2008; 104:53–61.
25. Pepin J. The origins of AIDS. New York:Cambridge University Press; 2011.
26. Sharp PM, Bailes E, Chaudhuri RH, Rodenburg CM, Santiago MO, Hahn BH. The origin of acquired immunodeficiency viruses: where and when?. Phil Trans R Soc Lond B 2001; 356:867–876.
27. Sharp PM, Hahn BH. Origin of HIV and the AIDS pandemic. Cold Spring Harb Perspect Med 2011; 1:a006841.
28. Kalish ML, Robbins KE, Pieniazek D, Schaefer A, Nzilambi N, Quinn TC, et al. Recombinant viruses and early global HIV-1 epidemic. Emerg Infect Dis 2004; 10:1227–1234.
29. Gilbert MTP, Rambaut A, Wlasiuk G, Spira TJ, Pitchenik AE, Worobey M. The emergence of HIV/AIDS in the Americas and beyond. Proc Natl Acad Sci U S A 2007; 104:18566–18570.
30. UNAIDS. HIV/AIDS: The global epidemic. Estimates as of December 1996.;jsessionid=2365BA90F2A65BDEDFD0E4BC0521582A?a=d&d=HASH01da2574c26597a69f118659.2&c=unaids&sib=1&dt=&ec=&et=&p.a=b&p.s=ClassifierBrowse& [30 Accessed January 2012]
31. United Nations. Redefining AIDS in Asia: crafting an effective response. Report of the Commission on AIDS in Asia. New Delhi: Oxford University Press; 2008.
32. Centers for Disease Control and Prevention. HIV/AIDS surveillance report. U.S. HIV and AIDS cases reported through December 1995. [Accessed 30 January 2012]
33. European Centre for the Epidemiological Monitoring of AIDS. HIV/AIDS surveillance in Europe. End year report 1999. [Accessed 30 January 2012]
34. Brookmeyer R. Reconstruction and future trends of the AIDS epidemic in the United States. Science 1991; 253:37–42.
35. Wiley JA, Coates TJ, Stall R, Saika G, Morin S, Charles K, et al. Reported changes in the sexual behavior of men at risk for AIDS, San Francisco, 1982-84: the AIDS Behavioral Research Project. Public Health Rep 1985; 100:622–629.
36. Becker MH, Joseph JG. AIDS and behavioral change to reduce risk: a review. Am J Public Health 1988; 78:394–410.
37. Colebunders R, Francis H, Izaley L, Kabasele K, Nzilambi N, Van Der Groen G, et al. Evaluation of a clinical case-definition of acquired immunodeficiency syndrome in Africa. Lancet 1987; 329:492–494.
38. WHO, UNAIDS, CDC. Guidelines for conducting HIV sentinel serosurveys among pregnant women and other groups. [Accessed 31 January 2012]
39. Pappaioanou M, Dondero T, Petersen L, Onorato I, Sanchez C, Curran JW. The family of HIV seroprevalence surveys: objectives, methods, and uses of sentinel surveillance for HIV in the United States. Public Health Rep 1990; 105:113–119.
40. Chin J. The AIDS pandemic. The collision of epidemiology with political correctness. Oxon:Radcliffe Publishing; 2007.
41. UNAIDS, WHO. AIDS epidemic update, December 2007. [Accessed 6 February 2012]
42. De Cock KM, DeLay P. HIV/AIDS estimates and the quest for universal access. Lancet 2008; 371:2068–2070.
43. Davis SF, Byers RH Jr, Lindegren ML. Prevalence and incidence of vertically acquired HIV infection in the United States. JAMA 1995; 274:952–955.
44. Davis SF, Rosen DH, Steinberg S, Wortley PM, Karon JM, Gwinn M. Trends in HIV prevalence among childbearing women in the United States, 1989–1994. J Acquir Immune Defic Syndr 1998; 19:158–164.
45. Rennie S, Turner AN, Mupenda B, Behets F. Conducting unlinked anonymous HIV surveillance in developing countries: Ethical, epidemiological, and public health concerns. PLoS Med 2009; 6:30–34.
46. Kreiss JK, Koech D, Plummer FA, Holmes KK, Lightfoote M, Piot P, et al. AIDS virus infection in Nairobi prostitutes. N Engl J Med 1986; 314:414–418.
47. Piot P, Plummer FA, Rey M-A, Ngugi EN, Rouzioux C, Ndinya-Achola J, et al. Retrospective seroepidemiology of AIDS virus infection in Nairobi populations. J Infect Dis 1987; 155:1108–1112.
48. DeCock KM, Odehouri K, Moreau J, Kouadio J, Porter A, Barrere B, et al. Rapid emergence of AIDS in Abidjan, Ivory Coast. Lancet 1989; 334:408–411.
49. De Cock KM, Barrere B, Diaby L, Lafontaine MF, Gnaore E, Porter A, et al. AIDS: the leading cause of adult death in the West African city of Abidjan, Cote d’Ivoire. Science 1990; 249:793–796.
50. Mann JM, Nzilambi N, Piot P, Bosenge N, Kalala M, Francis H, et al. HIV infection and associated risk factors in female prostitutes in Kinshasa, Zaire. AIDS 1988; 2:249–254.
51. Simonsen JN, Cameron DW, Gakinya MN, Ndinya-Achola JO, D’Costa LJ, Karasira P, et al. Human immunodeficiency virus infection among men with sexually transmitted infections. N Engl J Med 1988; 319:274–278.
52. Cameron DW, D’Costa LJ, Maitha GM, Cheang M, Piot P, Simonsen JN, et al. Female to male transmission of human immunodeficiency virus type 1: risk factors for seroconversion in men. Lancet 1989; 334:403–407.
53. Moss GB, Overbaugh J, Welch M, Reilly M, Bwayo J, Plummer FA. Human immunodeficiency virus DNA in urethral secretions in men: association with gonococcal urethritis and CD4 cell depletion. J Infect Dis 1995; 172:1469–1474.
54. Weiss HA, Buvé A, Robinson NJ, Van Dyck E, Kahindo M, Anagonou S, et al. The epidemiology of HSV-2 infection and its association with HIV infection in four urban African populations. AIDS 2001; 15 (Suppl 4):S97–S108.
55. Bongaarts J, Reining P, Way P, Conant F. The relationship between male circumcision and HIV infection in African populations. AIDS 1989; 3:373–377.
56. Clavel F, Guétard D, Brun-Vézinet F, Chamaret S, Rey M-A, Santos-Ferreira MO, et al. Isolation of a new human retrovirus from West African patients with AIDS. Science 1986; 233:343–346.
57. Adjorlolo G, De Cock KM, Ekpini E, Vetter KM, Sibailly T, Brattegaard K, et al. Prospective comparison of mother-to-child transmission of HIV-1 and HIV-2 in Abidjan, Ivory Coast. JAMA 1994; 272:462–466.
58. Kanki PJ, De Cock KM. Epidemiology and transmission of HIV-2. AIDS 1994; 8 (Suppl 1):S85–S93.
59. Marlink R, Kanki P, Thior I, Travers K, Eisen G, Siby T, et al. Reduced rate of disease development after HIV-2 infection as compared to HIV-1. Science 1994; 265:1587–1590.
60. Jaffar S, Grant AD, Whitworth J, Smith PG, Whittle H. The natural history of HIV-1 and HIV-2 infections in adults in Africa: a literature review. Bull World Health Organ 2004; 82:462–469.
61. DeCock KM, Adjorlolo G, Ekpini E, Sibailly T, Kouadio J, Maran M, et al. Epidemiology and transmission of HIV-2. Why there is no HIV-2 pandemic. JAMA 1993; 270:2083–2086.
62. Laga M, Piot P. Prevention of sexual transmission of HIV: real results, science progressing, societies remaining behind. AIDS 2012; 26:1223–1229.
63. Collins C, Coates TJ, Curran J. Moving beyond the alphabet soup of HIV prevention. AIDS 2008; 22 (Suppl 2):S5–S8.
64. Stoneburner RL, Low-Beer D. Population-level HV declines and behavioral risk avoidance in Uganda. Science 2004; 304:714–718.
65. UNAIDS. HIV Prevention needs and successes: a tale of three countries. An update on HIV prevention success in Senegal, Thailand and Uganda. 2001. [Accessed 6 February 2012]
66. Rojanapithayakorn W, Hanenberg R. The 100% condom program in Thailand. AIDS 1996; 10:1–7.
67. Ryder RW, Nsa W, Hassig SE, Behets F, Rayfield M, Ekungola B, et al. Perinatal transmission of the human immunodeficiency virus type 1 to infants of seropositive women in Zaire. N Engl J Med 1989; 320:1637–1642.
68. Dunn DT, Newell ML, Ades AE, Peckham CS. Risk of human immunodeficiency virus type 1 transmission through breastfeeding. Lancet 1992; 340:585–588.
69. DeCock KM, Fowler MG, Mercier E, de Vincenzi I, Saba J, Hoff E, et al. Prevention of mother-to-child HIV transmission in resource-poor countries. Translating research into policy and practice. JAMA 2000; 283:1175–1182.
70. Guay LA, Ruff AJ. HIV and infant feeding: an ongoing challenge. JAMA 2001; 286:2462–2464.
71. Nduati R, John G, Mbori-Ngacha D, Richardson B, Overbaugh J, Mwatha A, et al. Effect of breastfeeding and formula feeding on transmission of HIV-1. A randomized clinical trial. JAMA 2000; 283:1167–1174.
72. The Kesho Bora Study Group. Triple antiretroviral compared with zidovudine and single-dose nevirapine prophylaxis during pregnancy and breastfeeding for prevention of mother-to-child transmission of HIV-1 (Kesho Bora study): a randomised controlled trial. Lancet Infect Dis 2011; 11:171–180.
73. Thomas TK, Masaba R, Borkowf CB, Ndivo R, Zeh C, Misore A, et al. Triple-antiretroviral prophylaxis to prevent mother-to-child HIV transmission through breastfeeding: the Kisumu Breastfeeding Study, Kenya – a clinical trial. PLoS Med 2011; 8:1–12.
74. Chasela CS, Hudgens MG, Jamieson DJ, Kayira D, Hosseinipour MC, Kourtis AP, et al. Maternal or infant antiretroviral drugs to reduce HIV-1 transmission. N Engl J Med 2010; 362:2271–2281.
75. Vella S, Schwartländer B, Sow SP, Eholie SP, Murphy RL. The history of antiretroviral therapy and of its implementation in resource-limited areas of the world. AIDS 2012; 26:1231–1241.
76. Institute of Medicine. Preventing HIV infection among injecting drug users in high-risk countries. An assessment of the evidence. Washington, DC: The National Academies Press; 2006.
77. Moore A, Herrera G, Nyamongo J, Lacritz E, Granade T, Nahlen B, et al. Estimated risk of HIV transmission by blood transfusion in Kenya. Lancet 2001; 358:657–660.
78. Schutz R, Savarit D, Kadjo JC, Batter V, Kone N, Ruche LG, et al. Exclusion of high risk donors for reducing transfusion-transmitted HIV infection in a West African city. BMJ 1993; 307:1517–1519.
79. Dhingra N. Making safe blood available in Africa. Committee on International Relations. Subcommittee on Africa, Global Human Rights and International Operations. U.S. House of Representatives; 2006. [Accessed 1 February 2012]
80. Cardo DM, Culver DH, Ciesielski CA, Srivastava PU, Marcus R, Abiteboul D, et al. A case–control study of HIV seroconversion in healthcare workers after percutaneous exposure. N Engl J Med 1997; 337:1485–1490.
81. Ciesielski C, Marianos D, Ou C-Y, Dumbaugh R, Witte J, Berkelman R, et al. Transmission of human immunodeficiency virus in a dental practice. Ann Intern Med 1992; 116:798–805.
82. Centers for Disease Control. Recommendations for preventing transmission of human immunodeficiency virus and hepatitis B virus to patients during exposure-prone invasive procedures. MMWR 1991; 40 (RR-8):1–9.
83. Hersh BS, Popovici F, Jezek Z, Satten GA, Apetrei RC, Beldescu N, et al. Risk factors for HIV infection among abandoned Romanian children. AIDS 1993; 7:1617–1624.
84. Hersh BS, Popovici F, Zolotusca L, Beldescu N, Oxtoby MJ, Gayle DH. The epidemiology of HIV and AIDS in Romania. AIDS 1991; 5 (Suppl 2):S87–S92.
85. Yerli S, Quadri R, Negro F, Barbe KP, Cheseaux J-J, Burgisser P, et al. Nosocomial outbreak of multiple bloodborne viral infections. J Infect Dis 2001; 184:369–372.
86. Schmid GP, Buvé A, Mugyenyi P, Garnett GP, Hayes RJ, Williams BG, et al. Transmission of HIV-1 infection in sub-Saharan Africa and effect of elimination of unsafe injections. Lancet 2004; 363:482–488.
87. De Cock KM, Churchill D, Grant A, et al. Summary of Track B: clinical science. AIDS 1996; 10 (suppl 3):S107–S113.
88. CDC. Guidelines for human immunodeficiency virus case surveillance, including monitoring for human immunodeficiency virus infection and acquired immunodeficiency syndrome. MMWR 1999; 48 (No RR-13):1–27.
89. UNAIDS. World AIDS day report, 2011. How to get to zero: faster, smarter, better. [Accessed 1 February 2012]
90. World Health Organization. Global tuberculosis control 2011. [Accessed 15 February 2012]
91. Buvé A, Caraël M, Hayes RJ, Auvert B, Ferry B, Robinson NJ, et al. The multicentre study on factors determining the differential spread of HIV in four African cities: summary and conclusions. AIDS 2001; 15:S127–S131.
92. Tanser F, Barnighausen T, Hund L, Garnett GP, McGrath N, Newell M-L. Effect of concurrent sexual partnerships on rate of new HIV infections in a high prevalence, rural South African population: a cohort study. Lancet 2011; 378:247–255.
93. Prejean J, Song R, Hernandez A, Ziebell R, Green T, Walker F, et al.Estimated HIV Incidence in the United States, 2006–2009. PLoS One 2011; 6:e17502.
94. Pepin J. The origins of AIDS. New York: Cambridge University Press; 2011. pp. 215–220.
95. De Cock KM, Mbori-Ngacha D, Marum E. Shadow on the continent: public health and HIV/AIDS in Africa in the 21st century. Lancet 2002; 360:67–72.
96. Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, Kumarasamy N, et al. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med 2011; 365:493–505.
97. Montaner JSG, Lima VD, Barrios R, Yip B, Wood E, Kerr T, et al. Association of highly active antiretroviral therapy coverage, population viral load, and yearly new HIV diagnoses in British Columbia, Canada: a population-based study. Lancet 2010; 376:532–539.
98. Granich RM, Gilks CF, Dye C, De Cock KM, Williams BG. Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model. Lancet 2009; 373:48–57.
99. Williams BG, Granich R, De Cock K, Glaziou P, Sharma A, Dye C. Antiretroviral therapy for tuberculosis control in nine African countries. Proc Natl Acad Sci U S A 2010; 107:19485–19489.
100. Auvert B, Taljaard D, Lagarde E, Sobngwi-Tambekou J, Sitta R, Puren A. Randomized controlled intervention trial of male circumcision for reduction of HIV infection risk: the ANRS 1265 trial. PLoS Med 2005; 2:e298.
101. Bailey RC, Moses S, Parker CB, Agot K, Maclean I, Krieger JN, et al. Male circumcision for HIV prevention in young men in Kisumu, Kenya: a randomised controlled trial. Lancet 2007; 369:643–656.
102. Gray RH, Kigozi G, Serwadda D, Makumbi F, Watya S, Nalugoda F, et al. Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial. Lancet 2007; 369:657–666.
103. World Health Organization/Joint United Nations Programme on HIV/AIDS. WHO/UNAIDS technical consultation on male circumcision and HIV prevention: research implications for policy and programming. Conclusions and recommendations. Geneva: World Health Organization; 2007. [Accessed 16 February 2012]
104. WHO. Global HIV/AIDS response: epidemic update and health sector progress towards universal access: progress report 2011. [Accessed 16 February 2012]
105. Williams BG, Lloyd-Smith JO, Gouws E, Hankins C, Getz WM, Hargrove J, et al.The potential impact of male circumcision on HIV in sub-Saharan African populations. PLoS Med 2006; 3:1032–1040.
106. Cohen J. Breakthrough of the year. HIV treatment as prevention. Science 2011; 334:1628.
107. Shelton JD. ARVs as HIV prevention: a tough road to wide impact. Science 2011; 334:1645–1646.
108. Centers for Disease Control and Prevention. Vital signs: HIV prevention through care and treatment – United States. MMWR 2011; 60:1618–1623.
109. Centers for Disease Control and Prevention. HIV Surveillance Report. Vol. 21; 2009. [Accessed 1 February 2012]
110. Connor EM, Sperling RS, Gelber R, Kiselev P, Scott G, O'Sullivan MJ, et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment. N Engl J Med 1994; 331:1173–1180.
111. Guay LA, Musoke P, Fleming T, Bagenda D, Allen M, Nakabiito MB, et al. Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomised trial. Lancet 1999; 354:795–802.
112. WHO. Antiretroviral therapy for HIV infection in adults and adolescents. Recommendations for a public health approach: 2010 revision. [Accessed 1 February 2012]
113. WHO. Antiretroviral drugs for treating pregnant women and preventing HIV infection in infants. Recommendations for a public health approach (2010 version). [Accessed 1 February 2012]
114. WHO, UNICEF, UNFPA, UNAIDS. Towards the elimination of mother-to-child transmission of HIV. Report of a WHO technical consultation; 9–11 November 2010; Switzerland. [Accessed 2 February 2012]
115. Degenhardt L, Mathers B, Vickerman P, Rhodes T, Latkin C, Hickman M. Prevention of HIV infection for people who inject drugs: why individual, structural, and combination approaches are needed. Lancet 2010; 376:285–301.
116. Jaffe HW, Valdiserri RO, De Cock KM. The re-emerging HIV/AIDS epidemic in men who have sex with men. JAMA 2007; 298:2412–2414.
117. Centers for Disease Control and Prevention. Prevalence and awareness of HIV infection among men who have sex with men – 21 cities, United States, 2008. MMWR 2010; 59:1201–1207.
118. Smith AD, Tapsoba P, Peshu N, Sanders EJ, Jaffe HW. Men who have sex with men and HIV/AIDS in sub-Saharan Africa. Lancet 2009; 374:416–422.
119. UNAIDS, World Bank. New HIV infections by mode of transmission in West Africa: a multicountry analysis; March 2010. [Accessed 2 February 2012]
120. Halperin DT, Mugurungi O, Hallett TB, Muchini B, Campbell B, Magure T, et al. A surprising prevention success. Why did the HIV epidemic decline in Zimbabwe?. PLoS Med 2011; 8:e1000414.
121. Hargrove JW, Humphrey JH, Mahomva A, Williams BG, Chidawanyika H, Mutasa K, et al. Declining HIV prevalence and incidence in perinatal women in Harare, Zimbabwe. Epidemics 2011; 3:88–94.
122. Abdool Karim SSA, Abdool Karim QA. Antiretroviral prophylaxis: a defining moment in HIV control. Lancet 2011; 378:e23–e25.
123. Holmberg JA, Basavaraju S, Reed C, Drammeh B, Qualls M. Progress towards strengthening national blood transfusion services: 14 countries, 2008–2010. MMWR 2011; 60:1578–1582.

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