HIV-1 Molecular Epidemiology in Guinea-Bissau, West Africa: Origin, Demography and Migrations

Joakim Esbjörnsson,Patrik Medstrand,Mattias Mild,Fredrik Månsson,Hans Norrgren,Sheila Bowyer

doi:10.1371/journal.pone.0017025

Joakim Esbjörnsson, Patrik Medstrand + Show 4 more

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https://doi.org/10.1371/journal.pone.0017025

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Journal: PLoS ONE	Publication Date: Feb 18, 2011
Citations: 80	License type: CC BY 4.0

Affiliation: Lund University, Swedish Institute, Karolinska Institutet

Abstract

The HIV-1 epidemic in West Africa has been dominated by subtype A and the recombinant form CRF02_AG. Little is known about the origins and the evolutionary history of HIV-1 in this region. We employed Maximum likelihood and Bayesian methods in combination with temporal and spatial information to reconstruct the HIV-1 subtype distribution, demographic history and migration patterns over time in Guinea-Bissau, West Africa. We found that CRF02_AG and subsubtype A3 were the dominant forms of HIV-1 in Guinea-Bissau and that they were introduced into the country on at least six different occasions between 1976 and 1981. These estimates also corresponded well with the first reported HIV-1 cases in Guinea-Bissau. Migration analyses suggested that (1) the HIV-1 epidemic started in the capital Bissau and then dispersed into more rural areas, and (2) the epidemic in Guinea-Bissau was connected to both Cameroon and Mali. This is the first study that describes the HIV-1 molecular epidemiology in a West African country by combining the results of subtype distribution with analyses of epidemic origin and epidemiological linkage between locations. The multiple introductions of HIV-1 into Guinea-Bissau, during a short time-period of five years, coincided with and were likely influenced by the major immigration wave into the country that followed the end of the independence war (1963–1974).

Highlights

Human immunodeficiency virus type 1 (HIV-1) originated in West Central Africa via cross-species transmission from chimpanzees around the beginning of the 20th century, and has since diversified in the human population [1,2]
HIV-1 subtype A and CRF02_AG represents approximately 27% of the worldwide HIV-1 infections, most of them prevailing in West and Central Africa [23]
We studied 82 HIV-1 infected individuals from Guinea-Bissau, and found that 57% were infected with CRF02_AG and 21% with subtype A

Summary

Introduction

Human immunodeficiency virus type 1 (HIV-1) originated in West Central Africa via cross-species transmission from chimpanzees around the beginning of the 20th century, and has since diversified in the human population [1,2]. The most prevalent group of HIV-1 is the main (M) group which has been divided into subtypes (A–D, F–H, J–K), sub-subtypes (A1–A4, F1–F2) and 43 circulating recombinant forms (CRFs), distinguished on both the genetic level and geographic location [3]. Little is known about the HIV-1 population dynamics and migration events that have influenced the HIV-1 epidemic in countries in West Africa. The dominating form of HIV-1 in this region is the CRF02_AG, a recombinant between the subtypes A and G [10,11,12,13,14,15]. Most countries in West Africa reported an almost exponential increase in HIV-1 prevalence during the 1990’s, reaching a steady-state level of approximately one to six percent by the end of the 1990’s [16]. Andersson et al studied samples from 27 HIV-1 infected individuals collected 1994–1996 and found that 81% of the individuals were infected by CRF02_AG, 15% with subtype A, and one individual with subtype B [10]

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