Objective
To
identify unique characteristics of recent versus established HIV infections and
describe sexual transmission networks, we characterized circulating HIV-1
strains from two randomly selected populations of ART-naïve participants in
rural western Kenya.
Methods
Recent
HIV infections were identified by the HIV-1 subtype B, E and D, immunoglobulin
G capture immunoassay (IgG BED-CEIA) and BioRad avidity assays. Genotypic and
phylogenetic analyses were performed on the pol gene to identify transmitted drug resistance
(TDR) mutations, characterize HIV subtypes and potential transmission clusters.
Factors associated with recent infection and clustering were assessed by
logistic regression.
Results
Of
the 320 specimens, 40 (12.5%) were concordantly identified by the two assays as
recent infections. Factors independently associated with being recently
infected were age ≤19 years (P = 0.001) and history of sexually transmitted
infections (STIs) in the past six months (P = 0.004). HIV subtype distribution differed
in recently versus chronically infected participants, with subtype A observed
among 53% recent vs. 68% chronic infections (p = 0.04) and subtype D among 26%
recent vs. 12% chronic infections (p = 0.012). Overall, the prevalence of
primary drug resistance was 1.16%. Of the 258 sequences, 11.2% were in
monophyletic clusters of between 2–4 individuals. In multivariate analysis
factors associated with clustering included having recent HIV infection P = 0.043 and being from Gem region P = 0.002.
Conclusions
Recent HIV-1 infection was more frequent among 13–19 year
olds compared with older age groups, underscoring the ongoing risk and
susceptibility of younger persons for acquiring HIV infection. Our findings
also provide evidence of sexual networks. The association of recent infections
with clustering suggests that early infections may be contributing significant
proportions of onward transmission highlighting the need for early diagnosis
and treatment as prevention for ongoing prevention. Larger studies are needed
to better understand the structure of these networks and subsequently implement
and evaluate targeted interventions.
Below: Distribution of HIV-1 subtypes among participants, by recency of infection, Western Kenya, October 2003-May 2005
Full article at: http://goo.gl/B0sgNH
By:
Clement Zeh, Pauli N. Amornkul, Lisa A. Mills
US Centers for Disease Control and Prevention, Division of
HIV/AIDS Prevention (CDC), Kisumu, Kenya
Seth C. Inzaule, Lillian G. Nafisa, Alex Kasembeli, Fredrick
Otieno, Lisa A. Mills
Kenya Medical Research Institute (KEMRI)/CDC Research and
Public Health Collaboration, Kisumu Field Research Station, Kisumu, Kenya
Seth C. Inzaule, Pascale Ondoa
Amsterdam Institute of Global Health and Development
(AIGHD), Department of Global Health of the Academic Medical Center, Amsterdam,
The Netherlands
Hilde Vandenhoudt
Institute of Tropical Medicine (ITM), Antwerp, Belgium
John N. Nkengasong
Division of Global HIV and Tuberculosis, Center for Global
Health, CDC Atlanta, Georgia, United States of America
More at: https://twitter.com/hiv insight
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