Epidemiology and transmission of HIV-2. Why there is no HIV-2 pandemic

Km, De Cock; Adjorlolo, G; Ekpini, Ehounou R.; Sibailly, Toussaint S.; Kouadio, J; Maran, M.; Brattegaard, K.; Km, Vetter; Doorly, Ronan; Hd, Gayle

doi:10.1001/jama.270.17.2083

Cited by 147 publications

(93 citation statements)

References 27 publications

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“…Studies on other viruses have shown that viral load correlates well with the epidemiology of diseases. For example, the predominance of HIV-1 over HIV-2 has been suggested to be attributed to the higher viral load of HIV-1 (8) …”

Section: Discussionmentioning

confidence: 99%

Fecal Viral Load and Norovirus-associated Gastroenteritis

Chan¹,

Sung²,

Lam³

et al. 2006

Emerg. Infect. Dis.

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Section: Discussionmentioning

confidence: 99%

Fecal Viral Load and Norovirus-associated Gastroenteritis

Chan¹,

Sung²,

Lam³

et al. 2006

Emerg. Infect. Dis.

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“…2,6e8 It is thought that the long war that ravaged the country from 1963 to 1974 increasing the risk of sexual abuse and promiscuity, parenteral transmission through female ritual excision and multiple injections for the treatment of tuberculosis and the prevention of trypanosomiasis significantly contributed to its spread, 1,2,9 but its prevalence is now declining 10e12 The reasons for this decline are not clear as various data converge to show that survival is longer in patients infected with HIV-2 than in those infected with HIV-1, and that a larger percentage of HIV-2 infected individuals become long-term non-progressors 13,14 and therefore potentially contribute to the spread of the infection for a long time. On the other hand, the modest genital shedding of HIV-2 15e17 probably reduces the efficiency of sexual transmission, as suggested by the considerably slower spread of HIV-2 among sex workers 16,18 and the marked reduction in HIV-2 in Angola and Mozambique at the end of 1990s. 1 HIV-1 in Guinea-Bissau is mainly represented by the A/G (CRF 02_AG) recombinant strain, 19,20 and the finding of clusters, which contained sequences separated by short branches, suggests that the virus had time to evolve in the country.…”

Section: Introductionmentioning

confidence: 99%

Prevalence and risk determinants of HIV-1 and HIV-2 infections in pregnant women in Bissau

Gianelli

Riva

Bravo

et al. 2010

Journal of Infection

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Summary Objectives: To analyse the risk determinants of HIV-1 and HIV-2 infections in pregnant women in Bissau. Methods: Pregnant women attending the antenatal clinics of Bissau between January 2002 and June 2006 were consecutively tested unless they opted out. Results: Among 23,869 tested women the overall prevalence of HIV-1 was 5.7%, that of HIV-2 was 2.4%, and these included the 0.7% prevalence of HIV-1 and HIV-2 duals. The main factors associated with the risk of HIV-1 infection were older age, occupation and number of sexual partners. Beafada and Mandinga ethnic groups were at greater risk of presenting HIV-1, and Bijago and Papel at lower risk. The factors associated with the risk of HIV-2 were age, literacy and occupation; the Beafada were at greater risk than the other ethnic groups. Conclusions: The prevalence of HIV-2 infection decreased overtime, whereas that of HIV-1 infection remained substantially stable, but was higher than that observed in previous studies. The rapid decline in the rates of HIV-2 infection suggests that many of the factors that allowed its exponential growth in the past have now been partially removed, and that sexual and vertical transmission have not been sufficient to maintain and extend the epidemic.

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“…Whereas HIV-1 group M subtypes (A-D, F, H, J, and K) are spread globally, HIV-2 subtypes are mainly restricted to West Africa and can be categorized as epidemic subtypes (A and B) and nonepidemic subtypes (C-G) (4)(5)(6)(7). Biological reasons have been invoked to explain the difference in global epidemiology between HIV-1 and HIV-2, such as lower HIV-2 viral loads that correlate with a lower transmissibility (8)(9)(10). However, attempts to compare the history of the epidemics at their respective geographic origins are still lacking.…”

mentioning

confidence: 99%

Tracing the origin and history of the HIV-2 epidemic

Lemey

Pybus

Wang

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

311

195

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In this study we date the introduction of HIV-2 into the human population and estimate the epidemic history of HIV-2 subtype A in Guinea-Bissau, the putative geographic origin of HIV-2. The evolutionary history of the simian immunodeficiency virus sooty mangabey͞HIV-2 lineage was reconstructed by using available database sequences with known sampling dates, and a timescale for this history was calculated by using maximum likelihood methods. The date of the most recent common ancestor of HIV-2 subtype A strains was estimated to be 1940 ؎ 16 and that of B strains was estimated to be 1945 ؎ 14. In addition we used coalescent theory to estimate the past population dynamics of HIV-2 subtype A in a rural population of Guinea-Bissau. Parametric and nonparametric estimates of the effective number of infections through time were obtained for an equal sample of gag, pol, and env sequences. Our estimates of the epidemic history of HIV-2 subtype A in Guinea-Bissau show a transition from constant size to rapid exponential growth around 1955-1970. Our analysis provides evidence for a zoonotic transfer of HIV-2 during the first half of the 20th century and an epidemic initiation in Guinea-Bissau that coincides with the independence war (1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974), suggesting that war-related changes in sociocultural patterns had a major impact on the HIV-2 epidemic.T he AIDS epidemic is clearly recognized as a viral zoonosis (1-3). Phylogenetic analysis indicates that multiple interspecies transmissions from simian species have introduced two genetically distinct types of HIV into the human population: HIV-1, closely related to simian immunodeficiency virus (SIV) from chimpanzees (SIV CPZ ), and HIV-2, closely related to SIV from sooty mangabeys (SIV SM ). Whereas HIV-1 group M subtypes (A-D, F, H, J, and K) are spread globally, HIV-2 subtypes are mainly restricted to West Africa and can be categorized as epidemic subtypes (A and B) and nonepidemic subtypes (C-G) (4-7). Biological reasons have been invoked to explain the difference in global epidemiology between HIV-1 and HIV-2, such as lower HIV-2 viral loads that correlate with a lower transmissibility (8-10). However, attempts to compare the history of the epidemics at their respective geographic origins are still lacking.A useful strategy for investigating the epidemic history of HIV combines molecular clock analysis, to estimate the timescale of the epidemic, and coalescent theory, to infer the demographic history of the virus (11). Various molecular clock calculations have dated the most recent common ancestor (MRCA) of HIV-1 group M around 1930 Ϯ 15 (12-14). HIV-1 group M has subsequently spread globally, generating the pandemic observed today. Here, we investigate the epidemic history of HIV-2 to test previously suggested hypotheses of its origin. We provide the first estimated dates of cross-species transmissions of HIV-2. Our results indicate a transfer of HIV-2 subtypes A and B from sooty mangabeys to humans during the fi...

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Epidemiology and transmission of HIV-2. Why there is no HIV-2 pandemic

Cited by 147 publications

References 27 publications

Fecal Viral Load and Norovirus-associated Gastroenteritis

Fecal Viral Load and Norovirus-associated Gastroenteritis

Prevalence and risk determinants of HIV-1 and HIV-2 infections in pregnant women in Bissau

Tracing the origin and history of the HIV-2 epidemic

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