Hepatitis B among immigrants from Myanmar: Genotypes and their clinical relevance

Abstract

Hepatitis B virus (HBV) from 76 adult immigrants in Australia from Myanmar was characterized to determine the prevalence of different HBV genotypes and subgenotypes. A mutational analysis was then performed to determine the presence of clinically significant mutations and correlate them to clinical outcomes. Initial genotyping revealed 68 patients with genotype C (89.5%) and eight patients with genotype B (10.5%). Phylogenetic analysis revealed the large majority of the genotype C infections were of subgenotype C1 (67/68). Sequencing of the HBV polymerase gene (and overlapping surface gene) revealed no mutations associated with antiviral resistance. HBV surface gene mutations were detected in 10 patients with subgenotype C1. HBV BCP/PC sequencing was obtained for 71/76 (93%) patients. BCP and/or PC mutations were identified in 57/71 (80%) of PCR positive patients. Treatment had been commenced for 15/76 (18%) patients, a further 26 untreated patients were in a stage of disease where HBV treatment would be considered standard of care. It was identified that genotype C1 is the predominant sub-genotype in this population. Genotype C is known to be associated with increased risk of development of HCC. This highlights the need for screening for HCC given the potential for the development of liver cancer. It was also identified that people with HBV were potentially not receiving optimal therapy in a timely fashion.

Distribution of hepatitis B virus genotypes in general population of Myanmar via Nation wide study

“…In the current study, a relatively lower proportion (1.3%) of the study population tested positive for genotype B, sub-genotype B4 and B5. A previous study in the Yangon region had also reported the absence of B genotype in their study population [16]; however, inconsistent findings were reported in a study of Australian adult immigrants from Myanmar, where 10.5% of the study population were characterized as genotype B [34]. In our study, only 1.3% of the study population was found to have the HBV genotype B, thereby indicating that a low prevalence of this genotype was circulating in the country.…”

“…In this study, we determined a few sub-genotypes circulating in different parts of Myanmar, with the majority being sub-genotype C1. This was similar to the findings of HBV sub-genotypes found in United States-bound refugees from Myanmar, and adult immigrants to Australia from Myanmar [33][34]. Considering the sub-genotypes of HBV GENOTYPE C, at least two subtypes are found in Asia: HBV GENOTYPE C1 was found only in Southeast Asia including Vietnam, Myanmar and Thailand, while HBV GENOTYPE C2 was found in east Asia including Japan, Korea and China [27].…”

Distribution of hepatitis B virus genotypes in general population of Myanmar via Nation wide study

“…In this study, a few numbers of sub-genotypes circulate in different parts of Myanmar but majority was sub-genotype C1. It was quite similar findings with HBV sub-genotypes found in United States-bound refugees from Myanmar and adult immigrant in Australia from Myanmar [33][34].…”

Distribution of hepatitis B virus genotypes in general population of Myanmar via Nation wide study

“…In this study, a relatively lower portion (1.3%) of study population is found genotype HBV/B, subgenotype HBV/B4 and HBV/B5. The previous study in Yangon region also showed that the absence of B genotype was found in their study population [13] and discrepant findings with adult immigrants study in Australia where there was shown 10.5% of adult immigrant from Myanmar was characterized as genotype B [26]. This study showed only 1.3% of study population was found to be HBV/B genotype which indicated that low prevalence of this genotype was circulating in the country.…”

“…In this study, a few numbers of sub-genotypes circulate in different parts of Myanmar but majority was sub-genotype C1. It was quite similar sub-genotypes found in United States-bound refugees from Myanmar and adult immigrant in Australia from Myanmar [25][26].…”