Title: Evolution and Molecular Epidemiology of Subtype C HIV-1 in Zimbabwe
Authors: Dalai SC, de Oliveira T, Harkins GH, Kassaye SG, Lint J, Manasa J, Johnston E, Katzenstein D.
Journal: AIDS,23(18):2523-32 (2009)
Journal Impact Factor (I.F.): 5.46
Number of citations (Google Scholar): 40
Objective: To investigate the origins and evolutionary history of subtype C HIV-1 in
Zimbabwe in a context of regional conflict and migration.
Design: HIV-1C pol sequence datasets were generated from four sequential cohorts of
antenatal women in Harare, Zimbabwe sampled over 15 years (1991-2006).
Methods: One hundred and seventy-seven HIV-1C pol sequences were obtained from
four successive cohorts in Zimbabwe. Maximum-likelihood methods were used to
explore phylogenetic relationships between Zimbabwean HIV-1C sequences and
subtype C strains from other regions. A Bayesian coalescent-based framework was
used to estimate evolutionary parameters for HIV-1C in Zimbabwe, including origin
and demographic growth patterns.
Results: Zimbabwe HIV-1C pol demonstrated increasing sequence divergence
over the 15-year period. Nearly all Zimbabwe sequences clustered phylogenetically
with subtype C strains from neighboring countries. Bayesian evolutionary analysis
indicated a most recent common ancestor date of 1973 with three epidemic
growth phases: an initial slow phase (1970s) followed by exponential growth
(1980s), and a linearly expanding epidemic to the present. Bayesian trees provided
evidence for multiple HIV-1C introductions into Zimbabwe during 1979-1981, corresponding
with Zimbabwean national independence following a period of socio-political
Conclusion: The Zimbabwean HIV-1C epidemic likely originated from multiple introductions
in the late 1970s and grew exponentially during the 1980s, corresponding to
changing political boundaries and rapid population influx from neighboring countries.
The timing and phylogenetic clustering of the Zimbabwean sequences is consistent with
an origin in southern Africa and subsequent expansion. HIV-1 sequence data contain
important epidemiological information, which can help focus treatment and prevention
strategies in light of more recent political volatility in Zimbabwe
Citation: Dalai SC, de Oliveira T, Harkins GH, Kassaye SG, Lint J, Manasa J, Johnston E, Katzenstein D. Evolution and Molecular Epidemiology of Subtype C HIV-1 in Zimbabwe AIDS,23(18):2523-32 (2009).