STUDY ON MOLECULAR EPIDEMIOLOGY OF HIV AND HEPATITIS VIRUS INFECTIONS IN ASIA

(A)亚洲艾滋病毒的分子流行病学a1)越南北部的艾滋病毒暴发：我们调查了中越边境附近注射吸毒者（IDUs）中最近发生的艾滋病毒暴发的性质。HIV-1亚型E是分布在全国各地的主要毒株，与危险因素无关。我们发现，在越南北部的注射吸毒者中，大多数HIV-1亚型E与在中国广西萍乡市附近发现的HIV-1亚型E具有显著的聚类性，在V3环下游的12个氨基酸处共享独特的缬氨酸取代。数据表明，越南北部注射吸毒者中的艾滋病毒暴发是由最近引入的一种高度同质的E亚型变体（EV）引起的，其起源与邻近的中国南部流行的相似。2)在缅甸中部出现各种形式的HIV-1亚型间重组：除了之前在我们的研究中发现的两种HIV-1亚型B'和E外，我们还首次在缅甸中部发现了HIV-1亚型C。此外，大约1/4的标本显示gag （p17）和env （C2/V3）亚型不一致。重组断点分析显示存在新形式的HIV-1亚型间C/B‘和C/B’/E重组。这些数据表明，B′、C和E的多种亚型在缅甸中部共同传播，导致了亚型间重组新形式的进化。3)基因多态性对泰国人群HIV-1易感性和疾病进展的影响：对泰国不和谐夫妇的横断面研究显示，CCR5 927T突变是泰国人群HIV-1感染抗性的重要遗传易感性。这是在亚洲人群中做的第一个报告。这些结果将为亚洲这一特定地区未来的疫苗战略提供至关重要的信息。B)亚洲肝炎病毒的分子流行病学a1)东南亚HGV新基因型的鉴定：我们最近在东南亚国家发现了一种新的G型肝炎病毒（HGV）基因型。为了更详细地表征病毒基因组，我们克隆了属于新基因型的两种不同HGV分离株的全长核苷酸序列。这些分离株分别从缅甸（指定HGV-MY14）和越南（指定HGV-VT48）受试者的血清中分离得到。两个HGV分离株均由9228个核苷酸（nt）组成，具有一个8529 nt的开放阅读框，编码2843个氨基酸残基。2)HBV和HGV的PCR分型：为了确定HBV的A ~ F基因型和HGV的1 ~ 4基因型，我们开发了一种基于PCR的简单、精确的基因分型系统。用这种新方法调查了东南亚地区HBV和HGV基因型的流行情况。结果显示，缅甸和越南最常见的病毒基因型为HBV的C型和HGV的4型。有趣的是，乙型乙型肝炎病毒在越南也很流行。该检测系统被认为是HBV感染分子诊断和大规模调查的有用工具。少

(A)Molecular epidemiology of HIV in Asia1)HIV outbreaks in northern Vietnam : We have investigated the nature of recent HIV outbreaks among injecting drug users (IDUs) near Vietnam-China border. HIV-1 subtype E was a principal strain distributed throughout country, regardless of risk factor. We found that the majority of HIV-1 subtype E among IDUs in northern Vietnam showed the significant clustering with those found in nearby Pingxiang city of China's Guangxi Province, sharing a unique valine substitution at 12 amino acids downstream of the V3 loop. The data indicated that HIV outbreaks among IDUs in northern Vietnam was caused by the recent introduction of a highly homogeneous subtype E variant(EV) of close origin of that prevailing in nearby southern China.2)Emergence of various forms of HIV-1 intersubtype recombinants in Central Myanmar : In addition to two HIV-1 subtypes B' and E previously detected in our study, we have identified HIV-1 subtype C for the first time in Central Mya … More nmar. Moreover, approximately 1/4 of specimens showed the discordance in gag (p17) and env (C2/V3) subtypes. The recombination breakpoint analyses revealed the presence of new forms of HIV-1 intersubtype C/B' and C/B'/E recombinants. The data suggest that multiple subtypes of B', C and E are co-circulating in Central Myanmar, leading to the evolution of new forms of intersubtype recombinants.3)The genetic polymorphism influencing the susceptibility to HIV-1 and disease progression in Thai population : Cross-section study using discordant couples in Thailand revealed that CCR5 927T mutation is an important genetic predisposition related to resistance to HIV-1 infection in Thai population. This is one of the first reports done in Asian population. Theses results would provide the information crucial to future vaccine strategies for this particular areas in Asia.B)Molecular epidemiology of hepatitis viruses in Asia1)Identification of novel genotype of HGV in Southeast Asia : We recently identified a novel genotype of hepatitis G virus(HGV) in Southeast Asian countries. To characterize the viral genome in more detail, we cloned the full-length nucleotide sequence of the two different HGV isolates belonging to the novel genotype. These isolates were recovered from serum of Myanmarese (designated HGV-MY14) and Vietnamese (designated HGV-VT48) subjects, respectively. Both HGV isolates were composed of 9228 nucleotides (nt) and had a single open reading frame spanning 8529 nt and encoding 2843 amino acid residues.2)HBV and HGV genotyping by PCR : A simple and precise genotyping system based on PCR using the type-specific primers was developed in order to allow for the determination of genotypes A through F of HBV and genotypes 1 through 4 of HGV. By this new method, the prevalence of genotypes of HBV and HGV was investigated in Southeast Asia. The results revealed that the most common viral genotypes were type C of HBV and type 4 of HGV in Myanmar and Vietnam. Interestingly, type B of HBV was also prevalent in Vietnam. This assay system is considered to be useful tool for molecular diagnosis of HBV infection and large-scale surveys. Less