9-year HIV-2-associated mortality in an urban community in Bissau, west Africa

Poulsen, Anja; Aaby, Péter; Larsen, Olav; Jensen, Henrik; Nauclér, Anders; Lisse, Ida Maria; Christiansen, Claus; Dias, Francisco; Melbye, Mads

doi:10.1016/s0140-6736(96)04402-9

Cited by 120 publications

(85 citation statements)

References 18 publications

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Section: Discussionmentioning

confidence: 74%

“…An initiation of the epidemic at this time coincides with the time frame of the independence war (1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974) in Guinea-Bissau, a former Portuguese colony, and it has recently been hypothesized that this war in Guinea-Bissau played a critical role in the early dissemination of HIV-2 (27). There is evidence that both sexual and blood-borne HIV-2 transmission markedly increased during this period (27). Epidemiological linkage of HIV-2 with Portugal, established during the presence of the colonial army, was recognized when the first reported cases of HIV-2 in Europe were Portuguese veterans who had served in the army during the independence war (27,32).…”

Section: Discussionmentioning

confidence: 74%

“…26). Because of the surprisingly high HIV-2 seroprevalence in this region (26), it has been implicated as the possible nucleus of the HIV-2 epidemic (27). We reconstructed genealogies based on an equal sample of gag, pol, and env sequences (28).…”

Section: Resultsmentioning

confidence: 99%

“…There is evidence that both sexual and blood-borne HIV-2 transmission markedly increased during this period (27). Epidemiological linkage of HIV-2 with Portugal, established during the presence of the colonial army, was recognized when the first reported cases of HIV-2 in Europe were Portuguese veterans who had served in the army during the independence war (27,32). In Guinea-Bissau, HIV-2 seroprevalence was found to be consistently higher in older age groups (26,27).…”

Section: Discussionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

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

View full text Add to dashboard Cite

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“…Heterosexual transmission of HIV-2 seems to be less efficient compared to HIV-1 [13,14]. Further, progression to AIDS is slower in HIV-2-than in HIV-1-infected individuals [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Behaviour change and competitive exclusion can explain the diverging HIV-1 and HIV-2 prevalence trends in Guinea–Bissau

et al. 2007

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SUMMARYThe aim of this study was to determine whether a temporary rise in sexual risk behaviour during war in Guinea–Bissau could explain the observed trends in HIV-1 and HIV-2 prevalence, and to explore the possible contribution of competitive elimination of HIV-2 by HIV-1. A simulation model of the heterosexual transmission of sexually transmitted infections was parameterized using demographic, behavioural and epidemiological data from rural Guinea–Bissau, and fitted to the observed HIV-1 and HIV-2 trends with and without a historic rise in risk behaviour. The observed trends could only be simulated by assuming a temporary rise in risk behaviour. Around 30% of the projected decline in HIV-2 prevalence from a peak of 8·7% to 4·3% in 2010 was due to competitive elimination by HIV-1. Importantly for public health, HIV-1 prevalence was predicted to continue increasing and to become the dominant HIV type by 2010. Data collection is required to validate this prediction.

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HTLV-1 infection in a population-based cohort of older persons in Guinea-Bissau, West Africa: Risk factors and impact on survival

et al. 1998

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In 1989, a population‐based cohort of persons aged ≥50 years was established in an urban area of Guinea‐Bissau, West Africa. Overall, 346 persons were interviewed in detail about risk behaviors and had capillary blood drawn. Among women, 12.4% were HTLV‐1 seropositive, compared with 4.6% in men. No HTLV‐2 was found. Seropositivity varied considerably according to place of birth and ethnic group. In women, but not in men, HTLV‐1 seropositivity was strongly associated with early sexual debut (10–14 yrs, 33.3%; 15–17 yrs, 26.0%; 18–20 yrs, 6.5%; 21+ yrs, 0%; ptrend = 0.001), lifetime number of male partners (ptrend = 0.006), and the male partner's number of co‐wives (ptrend = 0.006). There was also a 3.1‐fold increased risk of being HTLV‐1 seropositive if the woman was also HIV‐2 seropositive. In a multivariate‐risk‐factor analysis, the strongest association with HTLV‐1 was a history of having been bitten by a monkey (n = 11; combined ORadjusted = 10.1; 95% CI 2.3–44.4). Ornamental scarification was associated with a 3.3‐fold increased risk. Ethnic affiliation also significantly influenced the risk of being HTLV‐1 seropositive. Follow‐up performed in January 1996 revealed no difference in survival between HTLV‐1‐seropositive and ‐seronegative individuals over 6 years (rate ratio = 1.4, 95% CI 0.7–2.8). In conclusion, this population, which has very high HIV‐2 seroprevalence, is also highly endemic for HTLV‐1. Whereas sexual behaviors are clearly important for HTLV‐1 spread in women, non‐sexual risk factors were the only ones of potential importance in men. HTLV‐1 had no impact on survival in this older population. Int. J. Cancer 76:293–298, 1998.© 1998 Wiley‐Liss, Inc.

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9-year HIV-2-associated mortality in an urban community in Bissau, west Africa

Cited by 120 publications

References 18 publications

Tracing the origin and history of the HIV-2 epidemic

Tracing the origin and history of the HIV-2 epidemic

Behaviour change and competitive exclusion can explain the diverging HIV-1 and HIV-2 prevalence trends in Guinea–Bissau

HTLV-1 infection in a population-based cohort of older persons in Guinea-Bissau, West Africa: Risk factors and impact on survival

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