Profiles of mutations in hepatitis B virus surface and polymerase genes isolated from treatment-naïve Nigerians infected with genotype E.

Introduction. Hepatitis B virus (HBV) infection is the leading cause of hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). HBV genotype E (HBV/E) is the predominant genotype in West Africa and has been linked epidemiologically with chronic and occult HBV infections as well as development of HCC. Mutations in the surface and polymerase genes of HBV have been associated with occult infection, drug resistance, vaccine escape, as well as HCC.Hypothesis/Gap Statement. There is limited data on the occurrence and patterns of mutations associated with occult infection, drug resistance, vaccine escape and HCC for HBV/E.Aim. This study characterized amino acid (aa) substitutions in the major hydrophilic (MHR) and reverse transcriptase (RT) regions of the surface and polymerase genes respectively of HBV sequences from a group of Nigerians with genotype E infection. The CpG islands of the PreC/C and PreS/S regions of these sequences were also described.Methodology. HBV surface and polymerase genes were detected using PCR techniques. Occurrence of new and previously described mutations in these genes were analysed using phylogenetic techniques.Results. Overall 13 HBV isolates were each sequenced for polymerase and surface genes mutations. Thirteen and nine PreS/S and PreC/C HBV genes respectively were analysed for CpG islands. Mutations in the MHR and a-determinants region of the S protein were discovered in eleven and nine of the 13 tested isolates respectively. These mutations were concomitant with aa changes in the RT functional domains of the isolates. Mutations associated with vaccine escape, occult infection and poor HCC prognosis were identified in HBV/E isolated in this study. Furthermore, all the isolates had at least one putative nucleotide analogue resistance mutations. Drug resistance mutations had the highest association with CpG islands.Conclusion. The results of this study contribute to further understanding of HBV variability in Nigeria and the West African region. This will aid the planning of adequate HBV immunization and treatment programmes for the countries in the region.

Laboratory diagnosis of a new outbreak of acute African swine fever in smallholder pig farms in Jos, Nigeria.

African swine fever (ASF) is a highly contagious fatal infectious disease of pigs and wild suids. The disease has a worldwide occurrence and significant impact on pig production. Two adult intensively raised large white boars from two farms in Jos with a history of sudden death were diagnosed of ASF between July and August 2019. Post-mortem examination of carcasses grossly showed splenomegaly, haemorrhagic lymphadenitis and hepatomegaly with severe congestion. The kidneys were enlarged and had generalized petechiae and blood clot in the pelvis. The heart was moderately enlarged. Microscopic examination of the spleen and lymph nodes revealed severe lymphocytic depletion, haemorrhage and severe haemosiderosis. The liver was severely congested with focal coagulative necrosis of the hepatocytes. The kidneys were severely congested and showed renal tubular necrosis with few tubular protein casts. Tissue samples were confirmed to be positive for African swine fever virus (ASFV) by polymerase chain reaction (PCR) assay, and phylogenetic analysis revealed that the isolate belonged to genotype I.