The findings of this study underscore the significantly increasing endemicity of hepatitis viruses, syphilis and HIV among the voluntary blood donors of our community. The pilot study indicates a high rate of prevalence of HBV DNA among HBsAg negative/anti-HBc positive donors and thus emphasizes the need for a more sensitive and stringent screening algorithm for blood donations.

Hepatitis B virus (HBV) has been classified into eight genotypes, and several subgenotypes, distinctly distributed geographically. The genotypes A and D were previously reported to be predominant in India. Recent studies indicated evidence of circulation of genotype C in Eastern part of India. With the aim to confirm the phylogenetic relation and molecular genetic characteristics of the HBV circulating in Kolkata, the most populous city in Eastern India, 11 strains were isolated and the complete genome sequences were analyzed. Phylogenetic analysis determined; three genotype C (adr-serotype) isolates closely related with C1 (Cs) subgenotype references from South East Asia, and three genotype A (adw2-serotype) isolates, related to Asia-variant references of subgenotype A1 (Aa). Whereas, five genotype D (ayw2, ayw3 serotype) isolates were highly divergent; one was related to subgenotype D1, two to subgenotype D3, and the remaining two clustered with a single genotype D isolate from Japan belonging to an unclassified subgenotype. Together, these two isolates differed from HBV D1-D4 subgenotypes by nucleotide differences ranging from 5.0 to 5.49%, probably indicating a new subgenotype, which we designate as D5. All serotype ayw3 of genotype D isolates had specific amino acid substitution Threonine at codon 118 and Methionine at codon 125 in antigenic determinant of surface gene that has not been reported previously in isolates from other parts of India. In conclusion; using the complete genome analyses this study has confirmed circulation of the genotype C in Eastern part of India and demonstrated considerable genotypic heterogeneity of the Indian genotype D.

The present study reports the genotypic distribution and the characteristics of partial genome sequences of HBV/C isolates from Eastern India. Low genetic diversity and confinement of HBV/C in Eastern India possibly indicate a recent, limited, spread in this region. Genotype C with T1762/A1764 mutation has been reported to increase the risk for hepatocellular carcinoma; therefore genotype C carriers in Eastern India should be carefully monitored.

Background: As the hepatitis B genotyping is important for assessing its clinical implications and geographical distribution, the sub-genotypes have been found useful for determination of specific genomic markers related to hepatocarcinogenesis. In Pakistan, there is no reported data on molecular evolutionary analysis of HBV. A study was, therefore, much needed to evaluate the spectra of mutations present in the strains prevalent here.

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