Search

Objective: There is a large number of immigrant workers from Cambodia and Myanmar in Thailand. The aim of our study was to determine seroprevalence and genotypes of hepatitis C virus (HCV) in this group. Methods: Immigrants aged between 15 and 60 years (1,431 Cambodians and 1,594 Myanmarese) were recruited into this study. Each sample was screened for anti-HCV by ELISA. RNA was extracted from seropositive samples and RT-PCR was performed in order to amplify the HCV core region. Each sample was subsequently sequenced, and the genotype was determined by phylogenetic analysis. Results: The prevalence of HCV infection in immigrant workers from Cambodia and Myanmar was 33 (2.3%) and 27 (1.69%) samples, respectively. Of the anti-HCV-positive individuals, 25 (75.8%) from Cambodia and 15 (55.6%) from Myanmar harbored viral RNA. Phylogenetic analysis showed that the predominant HCV genotypes in this group were 1a, 1b, 3a, 3b and 6 (6e, 6f, 6m, 6p and 6r). Most HCV isolates can be found in Thailand, though some subtypes of HCV-6 are uncommon. Conclusions: This study shows the HCV seroprevalence and genotypes among immigrant Cambodians and Myanmarese which may reflect the prevalence in each country and closely relate to the prevalence in the guest country. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Although hepatitis B virus (HBV) infection is endemic in Southeast Asia, molecular epidemiological data on HBV circulating in some countries are limited. The aims of this study were to evaluate the seroprevalence of HBV and its genetic variability among migrant workers from Cambodia, Laos, and Myanmar in Thailand. Sera collected from 1,119 Cambodian, 787 Laotian, and 1,103 Myanmarese workers were tested for HBsAg. HBV DNA was amplified and the pre-S/S region was sequenced for genotyping and genetic mutation analysis. HBsAg was detected in 282 (9.4%). The prevalence of HBsAg among migrant workers from Cambodia, Laos, and Myanmar was 10.8%, 6.9%, and 9.7%, respectively. Of 224 subjects positive for HBV DNA, 86% were classified as genotype C (99% were sub-genotype C1) and 11.6% were genotype B (30.8%, 34.6%, and 30.8% were sub-genotypes B2, B3, and B4, respectively). Various point mutations in the "a" determinant region were detected in approximately 18% of these samples, of which Ile126Ser/Asn was the most frequent variant. Sequencing analysis showed that 19.1% of samples had pre-S mutations, with pre-S2 deletion as the most common mutant (7.7%) followed by pre-S2 start codon mutation (3.8%) and both pre-S2 deletion and start codon mutation (3.3%). High prevalence of HBV infection (approximately 7-11%) was found among migrant workers from Cambodia, Laos, and Myanmar, which may reflect the current seroprevalence in their respective countries. The data also demonstrated that HBV sub-genotype C1 was the predominant strain and various mutations of HBV occurring naturally were not uncommon among these populations., ((c) 2010 Wiley-Liss, Inc.)