Viral Hepatitis
Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 15, 2004; 10(22): 3264-3268
Published online Nov 15, 2004. doi: 10.3748/wjg.v10.i22.3264
Hepatitis B virus genotypes, phylogeny and occult infection in a region with a high incidence of hepatocellular carcinoma in China
Zhong-Liao Fang, Hui Zhuang, Xue-Yan Wang, Xian-Min Ge, Tim J Harrison
Zhong-Liao Fang, Hui Zhuang, Department of Microbiology, School of Basic Medicine, Peking University Health Science Center, Beijing 100083, China
Xue-Yan Wang, Center for Disease Prevention and Control of Guangxi Zhuang Autonomous Region, Nanning 530021, Guangxi Zhuang Autonomous Region, China
Xian-Min Ge, Guangxi Worker Hospital, Nanning 530021, Guangxi Zhuang Autonomous Region, China
Tim J Harrison, Centre for Hepatology, Royal Free and University College Medical School, University College London, London, United Kingdom
Author contributions: All authors contributed equally to the work.
Supported by Beijing Municipal Committee of Science and Technology, No. H020920020190
Correspondence to: Professor Hui Zhuang, Department of Microbiology, School of Basic Medicine, Peking University Health Science Center, Beijing 100083, China. zhuanghu@publica.chinfo.net
Telephone: +86-10-82802221 Fax: +86-10-82801617
Received: December 19, 2003
Revised: February 4, 2004
Accepted: March 2, 2004
Published online: November 15, 2004
Abstract

AIM: To determine the genotypes and phylogeny of hepatitis B viruses (HBVs) in asymptomatic HBV carriers, and the prevalence of occult HBV infection in Long An County, Guangxi Zhuang Autonomous Region, an area with a high incidence of hepatocellular carcinoma.

METHODS: A nested polymerase chain reaction (nPCR) was used for detection of HBV DNA in serum samples from 36 blood donors with asympmatic HBV infection, and in serum samples from 52 HBsAg negative family members of the children who did not receive hepatitis B vaccination in Long An County. PCR products were sequenced, and the genotype of each HBV sequence was determined by comparison with sequences of known genotypes in the GenBank and EMBL nucleotide databases using the BLAST programme. Phylogenetic trees were constructed by the quartet maximum likelihood analysis using the TreePuzzle software.

RESULTS: Twenty (55.56%) of 36 HBV asymptomatic carriers were positive for HBV DNA. They were all genotype C by comparison with sequences of known genotypes in the GenBank and EMBL nucleotide databases. The full-length HBV DNA sequence isolated from the sample No. 624 contained 3215 bases. No interesting mutations were found in this isolate. The homology analysis showed that this strain was closer to the Vietnamese HBV genotype C strain, with a homology of 97%, compared its relation to the same genotype of HBV isolated in Shanghai. Six (11.5%) of the 52 HBsAg negative family members were positive for HBV DNA. A point mutation was found in the sample No. 37, resulting in the substitution of amino acid glycine to arginine in the “a” determinant. Other samples with positive HBV DNA did not have any unusual amino acid substitutions in or around the “a” determinant, and were attributed to the wild-type HBV.

CONCLUSION: The HBVs isolated from asymptomatic carriers of Long An County were all identified as genotype C, and the prevalence of occult HBV infection in the population of the county is as high as 11.5%. It is suggested that genotype C and persistent occult HBV infection may play an important role in the development of HCC in the county.

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