Molecular epidemiology of hepatitis B virus genotypes in blood donors in Islamabad, Pakistan.

Background: Hepatitis B virus (HBV) is a major causative agent of early, severe and prolonged liver infection that subsequently leads to cirrhosis of liver and hepatocellular carcinoma. The aim of this study was to evaluate the molecular epidemiology of hepatitis B virus (HBV) genotypes and comparison of serological assay performance versus polymerase chain reaction (PCR) in HBV screening.

Methods: Blood samples of 8517 healthy blood donors were collected during the period of January to June 2017 from Blood Bank of Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad. Samples were screened for HBsAg assay using technique of chemiluminescence immunoassay. PCR of positive samples was carried out using already reported genotype-specific primers by Naito . (2001). The results were confirmed by visualizing genotype bands.

Results: The study confirmed the presence of HBV in 2.5% of blood donors, and PCR confirmed the presence of HBV-DNA in 92 samples. The genotyping was done by PCR using type-specific primer sequences. PCR was dogged to check six genotypes, i.e., A, B, C, D, E, and F. The results of this study show high levels of Genotype D is this region, i.e., 52.17% with less dominating Genotype C, which is 16.30% with decreasing ratio of Genotype E (14.13%), Genotype A and B (9.78%), and mixed D + E (2.17%). The presence of coinfection is found at lowest rate. Due to the high percentage of HBV/D, it is concluded that D genotype is common in our population.

Conclusion: The most prevalent HBV genotype in ICT region was genotype D, which is responsible for liver cirrhosis and hepatocellular carcinoma. Efficacy of drugs varies with variation in genotypes of hepatitis B virus and also with geographical distribution.