RESUMO
Genotyping of 20 strains of Hepatitis B virus (HBV) from the Idu Mishmi primitive tribe of northeast India identified multiple genotypes and the presence of a unique cluster grouping with strains from Vietnam and Laos identified as novel recombinants/genotype I. Sequence analysis (similarity and bootscan plots) of three complete HBV genomes from the tribe provided evidence of recombination. Phylogenetic analyses supported recombination between genotypes A, G and C. The Pre-S gene between nt 2943 and 397 was clearly of genotype A origin, whereas nt 397-1397 represented genotype G and nt 1397-2943 represented genotype C. Percentage divergence from genotypes B, D, E, F, G and H varied from 9.2 +/- 0.45% to 13.8 +/- 0.53%, whereas genotype A and C differed by 7.9 +/- 0.42% and 7.4 +/- 0.39% respectively. The identification of similar recombinant viruses in three countries, especially in a primitive tribe with no contact with the outside world suggests that these viruses do not represent recent recombination events, but circulation of closely related viruses highly divergent from known HBV genotypes and should be classified as members of genotype 'I'.
Assuntos
DNA Viral/química , DNA Viral/genética , Vírus da Hepatite B/genética , Vírus da Hepatite B/isolamento & purificação , Hepatite B/virologia , Recombinação Genética , Análise por Conglomerados , Genoma Viral , Genótipo , Humanos , Índia , Dados de Sequência Molecular , Filogenia , Grupos Populacionais , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
BACKGROUND & OBJECTIVE: There is a paucity of information on distribution of hepatitis B genotypes from northeastern part of India. Arunachal Pradesh, one of the northeastern State of India bordering Bhutan, China and Myanmar, reported abnormally high numbers of hepatitis B surface antigen (HBsAg) positive cases in one of its districts during January-June 2005. We conducted this study in the subsequent months (August-December 2005) to know the prevalent genotypes by a rapid and specific method based on type-specific primers in Upper Dibang valley of Arunachal Pradesh. METHODS: A total of 438 randomly selected individual were screened for HBsAg positivity. Of the 93 HBsAg positive individuals, 36 HBsAg and HBV DNA positive samples were processed for HBV genotyping using type-specific primer based nested PCR (TSP-PCR). Representative samples were retested with RFLP-PCR based genotyping and nucleotide sequencing. RESULTS: Of the 36 samples, 29 (80.1%) could be genotyped by the TSP-PCR based method used. The predominant genotype was genotype A (41.6%) followed by genotypes C (27.8%) and D (11.1%). Seven isolates (19.9%) could not be genotyped by this method. INTERPRETATION & CONCLUSION: The presence of genotype C in this part of the country needs attention as genotype C takes a more aggressive disease course. Also, detection of genotype C in this isolated community bordering Tibet suggests viral gene flow from Tibet or other South-east Asian countries where genotype C of HBV is predominant.
Assuntos
Vírus da Hepatite B/classificação , Genótipo , Vírus da Hepatite B/genética , Índia , Filogenia , Reação em Cadeia da PolimeraseRESUMO
BACKGROUND & OBJECTIVE: Prevalence of injection drug users (IDUs) is high in the northeastern region of India. This coupled with unsafe injecting practices as well as practice of tattooing in remote tribal areas call for baseline data on the prevalence of parentally transmitted viral diseases. In the present study we aimed to measure the risk behaviours and seroprevalence of hepatitis C virus (HCV) antibodies amongst IDUs of Mizoram, a State of the northeast India. METHODS: A cross-sectional study was conducted in 2004-2005 amongst IDUs (including female sex workers) who had injected in the past six months and were unaware of their HCV/HIV status. They were recruited from various drop-in centers from Aizawl, Mizoram, and screened for anti-HCV antibodies using 3(rd) generation HCV EIA and recombinant immunoblot assay (RIBA). RESULTS: The prevalence of HCV antibodies was 71.2 per cent among the active IDUs. On univariate analysis increasing duration of injection, syringe sharing and heroin (diacetylmorphine) injectors were at a significantly higher risk of acquiring HCV antibodies (P<0.001). On multivariate analysis, HCV antibody prevalence showed a strong association with the type of drugs injected (P=0.001), frequency of injecting (P=0.013), multiplicity of drugs abused (P=0.004), and needle syringe sharing (P=0.003). INTERPRETATION & CONCLUSION: Unsafe injecting practices were found to be associated with a higher risk of acquiring hepatitis C infection. Our findings showed that syringe and needle exchange programme alone was not sufficient as a preventive strategy for control of hepatitis C infection among IDUs of Aizawl.
Assuntos
Hepatite C/etiologia , Abuso de Substâncias por Via Intravenosa/complicações , Adolescente , Adulto , Feminino , Anticorpos Anti-Hepatite C/sangue , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
AIM: To study the prevalence of hepatitis B virus (HBV) infection among an isolated tribe of Northeast India that migrated long back from Tibet. METHODS AND MATERIALS: Randomly selected 438 subjects from Idu Mishmi tribe of Arunachal Pradesh were screened for hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), hepatitis B surface antibody (anti-HBs), envelope antigen (HBeAg) using ELISA kits. RESULTS: The point prevalence of HBsAg was found to be 21.2% (93/438). Anti-HBc prevalence was 92.3% (193/209). Anti-HBs above 10 IU/ml were detected in 48% (96/200). Prevalence of HBeAg was higher (42.1%, 16/38) in children (less than 15 years) compared to adolescent and adults (32.7%, 18/55). History of hepatitis was significantly associated with positive HBsAg status (p < 0.000). CONCLUSION: Hepatitis B virus infection is hyperendemic among Idu Mishmi tribe of Arunachal Pradesh, India. Though, the route of transmission could not be ascertained, but the high HBV infection (78.6%) among less than 5 yrs and the finding of 58.4% of HBsAg positive mothers bearing HBsAg positive child indicates possibility of vertical transmission in this setting.