Age-specific prevalence of hepatitis B infection among the Karen in the Andaman and Nicobar Islands, India

Epidemiology of hepatitis B and C viral infections in Ladakh region

BACKGROUND

Little is known about the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in Ladakh, a mountainous region with low population density. We, therefore, determined these and tried to identify risk factors associated with these infections.

METHODS

Randomly selected residents of Ladakh region were tested for hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc) and antibodies to HCV (anti-HCV). A subset of HBsAg-positive persons were tested for hepatitis B e-antigen (HBeAg) and HBV DNA and those with anti-HCV for HCV RNA. Viral genotype was also determined.

RESULTS

Of the 2674 subjects, 141 (5.3%) tested positive for HBsAg, i.e. had current HBV infection and 339 (12.7%) tested positive for either HBsAg and or anti-HBc, i.e. had either current or past infection with HBV. Anti-HCV antibody was detected in 22 (0.8%) subjects. The HBsAg positivity rate was higher in Kargil district (8.3%) than in Leh district (3.3%). No particular risk factor was identified for either infection. Of the 141 and 22 specimens that contained HBsAg and anti-HCV, respectively (one had both), 74 and none tested positive for HBV DNA and HCV RNA, respectively. Of the 29 specimens that had sufficient HBV DNA for genotyping, 21, 7, and 1 specimens had HBV genotypes D, C, and A, respectively.

CONCLUSION

The overall prevalence of HBV infection seems to be higher in Ladakh region, especially the Kargil district. The prevalence of anti-HCV was similar to that in other parts of India. ᅟ ᅟ.

Molecular epidemiology of hepatitis B virus in primitive tribes of Odisha, eastern India

BACKGROUND AND OBJECTIVE

Among the indigenous population of India, Primitive Tribal Groups (PTGs) are vulnerable to various health related events and some of the PTGs are showing a decline in population associated with high mortality rates. The present study was undertaken to define the prevalence of Hepatitis B Virus (HBV) infection, its genetic characterization and possible risk factors for transmission in five PTGs in Odisha, India.

METHODS

Cross-sectional observational studies were carried out in the Lodha, Saora, Khadia, Mankidia, and Juanga tribes residing in different parts of Odisha between 2006 and 2010.

RESULTS

Hepatitis B surface antigen (HBsAg) prevalence was 0.8%, 0.9%, 0.9%, 3.7%, and 1.7% in Lodha, Saora, Khadia, Mankidia, and Juanga tribes, respectively. While 54.8% of seropositive (HBsAg) cases demonstrated HBV DNA, occult HBV infection was observed in 19.48% of cases. High viral load with detectable 'e' antigen was found in 29% of HBsAg-positive individuals. All HBV isolates (n=17) were genotype D without pre-core mutants. Only 15.6% of HBV positive individuals had symptoms of hepatic disease, though none had severe manifestations. Multivariate analysis of the prevailing risk factors indicated that shaving by the village barber was significantly associated with HBV transmission in males. Tattooing was found to be significantly associated with females.

INTERPRETATION AND CONCLUSION

This is the first report on HBV infection in PTGs of Odisha that suggests a high potential for transmission of HBV infection in two PTGs (Mankidia and Juanga). It warrants early public health attention in tribal populations vulnerable to HBV infection.

An overview of molecular epidemiology of hepatitis B virus (HBV) in India

Hepatitis B virus (HBV) is one of the major global public health problems. In India, HBsAg prevalence among general population ranges from 2% to 8%, placing India in intermediate HBV endemicity zone and the number of HBV carriers is estimated to be 50 million, forming the second largest global pool of chronic HBV infections. India is a vast country, comprised of multiracial communities with wide variations in ethnicity and cultural patterns, which is attributable to its geographical location, gene influx due to invasion and/or anthropological migrations in the past. Moreover, recent increase in trade, trafficking and use of illicit drugs has also considerably influenced the epidemiology of HBV, specifically in the eastern and north eastern parts of India. However, data on the molecular epidemiology of HBV in India is scanty. HBV genotypes A and D have been well documented from different parts of mainland India. Interestingly, in addition to genotypes A and D, genotype C having high nucleotide similarity with south East Asian subgenotype Cs/C1 strain, have been detected exclusively from eastern Indian HBV carriers, suggesting a recent introduction. Thus, compared to other parts of India, the molecular epidemiology of HBV is naturally distinct in eastern India. Very recently, taking the advantage of circulation of three distinct HBV genotypes within the population of eastern India, different aspects of HBV molecular epidemiology was studied that revealed very interesting results. In this study, the clinical significance of HBV genotypes, core promoter and precore mutations, possible routes of introduction of HBV genotype C in eastern India, the clinical implications of x gene variability, prevalence of the AFB₁ induced p53 gene codon 249 mutation, the transmission potentiality of HBV among asymptomatic/inactive or occult HBV carriers and the genetic variability of HBV persisting in the PBL was investigated. In this manuscript, the information available on the molecular epidemiology of HBV in India has been reviewed and the results of studies among the eastern Indian population have been summarised.

Predominance of hepatitis B virus genotype C among Karens, the 'old settlers' of Andaman and Nicobar Islands, India

The Karens, or 'old settlers', migrated from Myanmar to Andaman and Nicobar islands 80 years ago. A high HBV exposure rate among them has been reported. A study of 34 HBsAg carriers was done to investigate the origin of HBV infection among the Karens. RFLP-based genotyping was confirmed by sequencing and phylogenetic analysis. The predominance of HBV/C1/Cs suggests that they carried HBV during their migration, retained it, and in addition, acquired HBV/D2 from the people of mainland India. The reported association of HBV genotype C with disease severity thus warrants further epidemiological investigations among them and on possible spread among neighboring settlers.

Hepatitis delta virus infection among the tribes of the Andaman and Nicobar Islands, India

Hepatitis B virus infection is highly endemic among the tribes of Andaman and Nicobar Islands, India. We screened 223 hepatitis B surface antigen-positive members of these tribes for hepatitis delta virus infection (HDV). The infection was observed only among the Nicobarese. Considering the serious consequences of HDV infection, we suggest that the tribes of these islands should be monitored for HDV infection.