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Molecular epidemiological study of hepatitis B virus in Thailand based on the analysis of pre‐S and S genes
Author(s) -
Suwannakarn Kamol,
Tangkijvanich Pisit,
Thawornsuk Nutchanart,
Theamboonlers Apiradee,
Tharmaphornpilas Piyanit,
Yoocharoen Pornsak,
Chongsrisawat Voranush,
Poovorawan Yong
Publication year - 2008
Publication title -
hepatology research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.123
H-Index - 75
eISSN - 1872-034X
pISSN - 1386-6346
DOI - 10.1111/j.1872-034x.2007.00254.x
Subject(s) - hbsag , hepatitis b virus , genotype , virology , biology , mutation , hepatitis b , gene , virus , medicine , genetics
Aims: This study was undertaken to determine the prevalence and characteristics of hepatitis B virus (HBV) genotypes, antigen subtypes, “a” determinant variants and pre‐S gene mutations circulating on a large scale in Thailand. Methods: The sequences of the Pre‐S1 , Pre‐S2 and S regions were determined in serum samples of 147 HBsAg and HBV DNA‐positive subjects who had been enrolled from the nationwide seroepidemiological survey conducted on 6213 individuals in 2004. Results: The results showed that genotypes C, B and A accounted for 87.1%, 11.6% and 1.3%, respectively. The distribution of the HBV antigen subtypes was: adr (84.4%), adw (14.2%) and ayw (1.4%). Regarding the “a” determinant, 2/43 (4.65%) and 2/104 (1.92%) samples of vaccinated and non‐vaccinated subjects, respectively, displayed mutations, all ofwhich were Thr126Asn. Sequencing analysis showed the pre‐S mutations in 14 (9.5%) samples, with pre‐S2 deletion as the most common mutant (4.1%) followed by pre‐S2 start codon mutation (2.9%), both pre‐S2 deletion and start codon mutation (2.0%), and pre‐S1 deletion (0.7%). The pre‐S mutations were associated with older age and higher mean serum HBsAg level. Conclusion: This study demonstrated that HBV genotype/subtype C/adr and B/adw were the predominant strains circulating in Thailand. The “a” determinant variants seemed to be uncommon, and might not be attributed to vaccine‐induced mutation.