Hepatitis C virus genotype distribution in Myanmar: Predominance of genotype 6 and existence of new genotype 6 subtype

Lwin, Aye Aye; Shinji, Toshiyuki; Khin, Myo; Win, Ne; Obika, Mikako; Okada, Shigeru; Koide, Naoki

doi:10.1111/j.1872-034x.2007.00053.x

Cited by 63 publications

(63 citation statements)

References 36 publications

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“…Of course, not all HCV infections in East Asia are caused by genotype 6, and the genotype distribution of HCV infection is variable among and within different East Asian countries. For example, genotype 6 appears to be the most frequent genotype in Myanmar (49% of infections) (29) and Vietnam (52% of infections) (37), but not in Thailand, where the globally distributed subtype 3a, which is associated with injection drug use, is twice as common as genotype 6 (23). The most common strain in China is the global subtype 1b (5), although subtype 6 is found at higher frequencies in southern China (27) and Hong Kong (42,71).…”

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confidence: 99%

“…1, genotype 6 isolates have been obtained from residents or emigrants of Thailand, India, Cambodia, Laos, Myanmar (Burma),Vietnam, China, Hong Kong, and Indonesia (25,46). The prevalence of HCV in the general population is variable among East Asian countries, ranging from about 0.5% in Singapore and Hong Kong, to around 6% in Vietnam and Thailand (69), and exceeding 10% in Myanmar (29). The reported prevalence in China is approximately 2 to 3%, which amounts to approximately 30 million people (22,70).…”

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Genetic History of Hepatitis C Virus in East Asia

Pybus

Barnes

Taggart

et al. 2009

J Virol

196

213

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The hepatitis C virus (HCV), which currently infects an estimated 3% of people worldwide, has been present in some human populations for several centuries, notably HCV genotypes 1 and 2 in West Africa and genotype 6 in Southeast Asia. Here we use newly developed methods of sequence analysis to conduct the first comprehensive investigation of the epidemic and evolutionary history of HCV in Asia. Our analysis includes new HCV core (n ‫؍‬ 16) and NS5B (n ‫؍‬ 14) gene sequences, obtained from serum samples of jaundiced patients from Laos. These exceptionally diverse isolates were analyzed in conjunction with all available reference strains using phylogenetic and Bayesian coalescent methods. We performed statistical tests of phylogeographic structure and applied a recently developed "relaxed molecular clock" approach to HCV for the first time, which indicated an unexpectedly high degree of rate variation. Our results reveal a >1,000-year-long development of genotype 6 in Asia, characterized by substantial phylogeographic structure and two distinct phases of epidemic history, before and during the 20th century. We conclude that HCV lineages representing preexisting and spatially restricted strains were involved in multiple, independent local epidemics during the 20th century. Our analysis explains the generation and maintenance of HCV diversity in Asia and could provide a template for further investigations of HCV spread in other regions.

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confidence: 99%

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Genetic History of Hepatitis C Virus in East Asia

Pybus

Barnes

Taggart

et al. 2009

J Virol

196

213

View full text Add to dashboard Cite

show abstract

“…Studies indicate that HCV genotype 6 is responsible for 50% of HCV infections in Myanmar and Vietnam (17,18). Moreover, genotype 6 is the second most common HCV genotype among blood donors in Hong Kong (19).…”

Section: Discussionmentioning

confidence: 99%

Hepatitis C Virus Subtype 6a Infection in an Iranian Patient: A Case Report

Moghadam

Mohebbi

Hosseini

et al. 2013

Jundishapur J Microbiol

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Hepatitis C virus (HCV) isolates have been divided into six major genotypes, each of them further divided into several subtypes. Previous studies have shown that the most frequent genotype in Iranian patients with HCV infection is 1a, followed by 3a, 1b and 4. Infections with genotype 6 isolates have not previously been observed in these patients. In this report, we will describe the first diagnosis of HCV genotype-6 infection in Iran. The case was a 62-year-old man with positive anti-HCV antibody. Alanine aminotransferase and aspartate aminotransferase levels were 14 and 32 IU/L respectively. Viral RNA was extracted from plasma. HCV RNA level was determined using real-time reverse transcription polymerase chain reaction (PCR). Following the synthesis of the complementary DNA, 5'-UTR/core region of the HCV genome was amplified and subjected to direct sequencing. Genetic distances were estimated and phylogenetic tree was constructed. HCV viral load was 9,572,718 IU/mL. The mean inter-genotypic distance between the case sequence and the corresponding sequences of other genotype 6 isolates was 3.7%. In the phylogenetic tree, the 5'-UTR/core sequence of the subject was located in a cluster representing HCV subtype 6a. The patient was infected with HCV subtype 6a. Prior to this case, there have been no previous reports on the isolation of this genotype/subtype from any other Iranian patient. Previous epidemiological studies provide valuable information about the distribution patterns of different HCV genotypes. However, infection with genotypes other than common ones should be flagged by specialists and diagnostic laboratories, especially in patients with high-risk behavioral backgrounds.

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“…The first type corresponds to isolates showing genetic diversities that are great enough to classify them into new subtypes. Among them, NK046, CMBD-14 and CMBD-86 formed one cluster and DH012, MYAN-3E-3 and MYAN-TC-148 constituted a second cluster (Shinji et al, 2004;Lwin et al, 2007). Single variants IG57272, QC56, QC81, QC112, QC148, QC251 and QC269, characterized in both E1 and NS5B, may be analogous to km41 and gz52557 .…”

Section: Discussionmentioning

confidence: 99%

“…Analysed with core and NS5B region sequences, DH012 (GenBank accession nos EU081431 and EU081498) clustered with MYAN-3E-3 (AB103143 and AB254861) and MYAN-TC148 (AB269346 and AB269353), which were isolated in Myanmar (Shinji et al, 2004;Lwin et al, 2007). Using E1 gene sequences for analysis, NK046 (GenBank accession no.…”

Section: Lu and Others 448mentioning

confidence: 99%

Complete genomes of three subtype 6t isolates and analysis of many novel hepatitis C virus variants within genotype 6

Lü

Murphy

et al. 2008

Journal of General Virology

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In this study, the complete genomic sequence was determined for three hepatitis C virus variants (VT21, TV241 and TV249) of genotype 6 that do not classify within the established subtypes. All three genomes were isolated from patients in Vietnam and sequenced using 100 ml of serum. They showed 91.4-93.6 % nucleotide similarities to each other but only 71.7-79.4 % similarities to 17 reference sequences representing subtypes 6a-6q and to isolates km41 and gz52557. VT21, TV241 and TV249 displayed genome lengths of 9407, 9460 and 9445 nt, respectively. All three isolates contained a single open reading frame of 9051 nt while the 59UTRs and 39UTRs were 324-338 nt and 32-71 nt, respectively. They shared common sizes with QC227/6o and QC216/6p isolates in all ten protein regions. Phylogenetic analyses demonstrated that VT21, TV241 and TV249 clustered independently and were assigned subtype 6t, following the recent designations of 6r and 6s. Analysis of partial genomic sequences available for genotype 6 variants revealed five additional subtype 6t isolates, all originating from Vietnam. This analysis revealed two additional groups of isolates, and at least seven novel variants analogous to km41 and gz52557 that group independently and do not classify within the subtypes 6a-6t. This suggests the existence of at least 11 additional subtypes for genotype 6. In addition, the existence of isolates showing genetic distances greater than those within subtypes, but lesser than those between subtypes, raises interesting questions regarding the classification of HCV.

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Hepatitis C virus genotype distribution in Myanmar: Predominance of genotype 6 and existence of new genotype 6 subtype

Abstract: The results indicate there are regional differences of HCV genotype distribution in Myanmar. There is a distinct geographic variation from other South-East Asian countries in terms of the existence of the new genotype 6 subtype.

Cited by 63 publications

References 36 publications

Genetic History of Hepatitis C Virus in East Asia

Genetic History of Hepatitis C Virus in East Asia

Hepatitis C Virus Subtype 6a Infection in an Iranian Patient: A Case Report

Complete genomes of three subtype 6t isolates and analysis of many novel hepatitis C virus variants within genotype 6

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