Migrant workers play a key role in HIV-1 strain diversity in Bangladesh

Introduction
Bangladesh is a low prevalence country for human immunodeficiency virus (HIV), and genotyping data is limited which is incomplete and mainly subtype C based on gag gene. In the present paper, we characterized HIV-1 strains obtained from individuals attending three HIV testing and counseling (HTC) centers from different geographic regions in Bangladesh comprehensively based on three genes.

Material and methods
A total of 40 HIV-positive blood specimens with demographic and migration history were available from individuals who attended HTC centers during 2005-2007. DNA was extracted from whole blood and sequenced using primers specific for gag, pol, and env region of HIV genome.

Results
Sub-type C was the most predominant strain (45%) followed by G-related recombinants (35%). Other genotypes were A1 (5%), B (2.5%), CRF16_A2D (7.5%), and unique recombinant form (5%). Phylogenetic analysis indicates that the origins of these strains varied and most of them might have been imported from the Middle East on a regular basis by migrant workers.

Conclusions
This is the first study to describe comprehensive characterization of Bangladeshi HIV-1 strains. Adapted intervention programs relating to appropriate counseling and provision of information relating to risk of transmission of HIV need to aim at returnee migrant workers.