Prevalence and Genotypic Characterization of Hepatitis B Virus among Outpatient Attendees at Moi Teaching and Referral Hospital, Eldoret

Abstract

Hepatitis B virus (HBV) infection remains one of the major worldwide public health burdens and a major cause of hepatocellular carcinoma. There is growing evidence that HBV genotypes influence not only clinical outcomes of HBV infection, but response to therapy and vaccination. Although HBV prevalence among the rural populations in Kenya is increasing, there is limited information on the circulating genotypes. This study aimed to evaluate the prevalence and genetic diversity of HBV among outpatient clinic attendees at Moi Teaching and Referal Hospital in Eldoret. A cross-sectional laboratory based study was conducted, where blood samples were collected from a total of 200 study participants. Enzyme-Linked Immunosorbent Assay (ELISA) screening was done for the presence of HBV surface antigen (HBsAg). From the positive samples, molecular analysis was done by first extracting the viral DNA followed by amplification, to yield enough materials that were then sequenced and the sequences aligned and compared with the reference sequences retrieved from the GeneBank. The study determined a general prevalence of HBV infection of 10% (20/200). Demographically males accounted for 60% of infection compared to the females. Further HBV infection was higher in those aged 31-40 years who accounted for 35% of the total infections. On the likelihood of infections, there was no significant association of infection with gender and age (p=0.149) and (p=0.070) respectively, where males were 6 times more likely to be infected (OR = 1.286; p= 0.149) and those aged between 31–40, showing a higher likelihood of infection (OR = 1.447, p=0.070). Of the 14 HBsAg positive samples sequenced, HBV subgenotype A1 (HBV/A1) accounted for 92.9% (13/14) of all infections with the remaining 1 sample belonging to subgenotype D1. Analysis on mutations revealed occurance of the mutations within the Major Hydrophilic Region (MHR), with the main mutation being S114T. Phylogenetic analysis revealed that 14 isolate sequences with reference sequences obtained from GenBank; 13 (92.9%) of the isolates classified into subgenotype A1 (HBV/A1), while 1 (7.1%) of isolates categorized into subgenotype D1 (HBV/D1). In conclusion, the general prevalence observed in this study shows a potential for a higher rate of transmission of HBV in this population. The genetic diversity analysis however reveals that the circulating genotype is still restricted and could be possible source of HBV transmission in the community. The study recommends that campaigns for VCT in HBV should be enhanced among the public and that HBV Diversity in the country should be considered when designing interventions for HBV.