Characterization of Circulating Hepatitis B Virus Genotypes among Inmates and Low Risk Voluntary Blood Donors in Garissa County, Kenya
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Date
2023-12
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Kenyatta University
Abstract
Hepatitis B virus (HBV) infection is a life-threatening infection that attacks the liver and can cause both acute and chronic disease. This creates a high risk of death from cirrhosis and liver cancer. Hepatitis B infection poses a major health concern globally. It is estimated that in 2019, about 296 million people had been chronically infected with HBV globally and about 820, 000 deaths from hepatocellular carcinoma and cirrhosis were reported. In Kenya, HBV prevalence stands at chronic states of intermediate range (5-7%) and high (>8%) with regional variations. Garissa County carries a high HBV infection risk with a reported prevalence of 14.1% in pregnant women attending antenatal care (ANC) clinics. This study sought to determine the seroprevalence and circulating Hepatitis B virus genotypes among the prisoners and compare it with that of the surrounding general population at Garissa County Referral Hospital in Garissa, Kenya. A total of 130 in-mates and 130 voluntary blood donors were randomly sampled in this study and a questionnaire used to collect data on their socio-demographic characteristics. Blood was then collected in plain vacutainers and the resulting serum tested for Hepatitis B surface antigen (HBsAg) using a rapid test strip. HBV DNA was then extracted from the serum and a 930bp region of the overlapping HBV P/S gene amplified and sequenced using Sanger method. Logistic regression was used to evaluate socio-demographic factors associated with HBV seropositivity. Resulting HBV DNA sequences were manually edited, assembled into contigs and then aligned. Genotype identity of the aligned sequences was initially made using the Geno2pheno [hbv] 2.0 online data base. The aligned sequences from this study and genotype specific sequences in Genbank were then used to infer phylogenetic relationships of the local strains. The Geno2pheno [hbv] 2.0 online data base was further used to identify mutations in the samples associated with diagnostic failure and vaccine failure (in the S gene) and antiviral resistance (in the P gene). Majority of the study participants were males (86.9% among inmates and 95.4% among blood donors. Majority (76.2%) of the in-mates and of the donors (83.1%) were aged between 20-40 years while majority (51.4 % of the donors and 81.5% of in mates) had only a primary school level of education. HBV seroprevalence was significantly higher among in-mates compared to blood donors. Out of the total number of in-mates tested, 7 (5.4%) were HBYV seropositive. Conversely, among blood donors 4 (3.1 %) were seropositive. There was a significant association between HBV seropositivity and gender among both the blood donors and inmates. Out of the 22 HBV-DNA positive samples, genotype D was the most prevalent among both the in-mates and blood donors (81.8%). Genotype A sub-genotype Al was only detected among the in-mate population (18.2%). All the genotype D sequences were found to be either D/A or D/E recombinants. HBsAg escape mutations associated with diagnostic failure were noted among both study populations. As a pioneer study on HBV in Kenyan prisons, the current study confirms the categorization of in-mates as HBV high risk populations. The dominance of HBV genotype D is a novel finding as studies in other regions of the country have identified genotype A as the most prevalent. To control spread of HBV infection, serological testing should be followed up with PCR testing methods to avoid diagnostic failure.
Description
A Research Thesis Submitted in Partial Fulfilment of Requirements for the Award of the Degree Of Master of Science in Infectious Diseases in the School of Health Sciences, Kenyatta University, December 2023.
Supervisor
George Gachara
Wallace Bulimo