title: Detection of hepatitis B virus isolates with mutations associated with immune escape mutants among pregnant women in Ibadan, southwestern Nigeria.
abstract: Perinatal transmission of hepatitis B virus (HBV) and its associated immune escape mutants (IEMs), is the major vehicle through which a population of chronically infected people who serve as infectious HBV reservoirs is maintained in communities. Therefore, to assess the risk of perinatal transmission, 272 pregnant women attending ante-natal clinics in Ibadan metropolis, southwestern, Nigeria, were screened for HBsAg using ELISA technique. Samples positive for HBsAg were subjected to HBV DNA detection by PCR amplification of the S-gene and amplicon sequencing. Isolates were genotyped and subtyped using a combination of molecular techniques. Fifteen (5.5%) of the pregnant women were positive for HBsAg of which HBV DNA was detected in seven. Five of the isolates were typed as genotype E subtype ayw4 using amino acid residues at positions 122, 127, 134 and 160. Another could only be typed as genotype E subtype ayw4 by further phylogenetic analysis. The remaining one isolate did not belong to any of genotypes A - H. Three of the HBV isolates including the untypable, had mutations in the 'a' determinant associated with IEMs. This study confirms the endemicity of HBV, the risk of perinatal transmission and the circulation of genotype E subtype ayw4 in Nigeria. It further demonstrates the presence of IEMs in Nigeria.
authors: Department of Virology, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria ; Department of Microbiology, Faculty of Science, Ekiti State University, Ado Ekiti, Ekiti State Nigeria.
authors: Temitope Oluwasegun Cephas
authors: TO
authors: Faleye
authors: Department of Virology, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria.
authors: Moses Olubusuyi
authors: MO
authors: Adewumi
authors: Department of Surgery, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria.
authors: Ijeoma Maryjoy
authors: IM
authors: Ifeorah
authors: Institute of Child Health, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria.
authors: Ewean Chukwuma
authors: EC
authors: Omoruyi
authors: Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria.
authors: Solomon Adeleye
authors: SA
authors: Bakarey
authors: Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria.
authors: Adegboyega
authors: A
authors: Akere
authors: Department of Science Laboratory Technology, Faculty of Science, Ekiti State University, Ado Ekiti, Ekiti State Nigeria.
authors: Funmilola
authors: F
authors: Awokunle
authors: Department of Microbiology, Faculty of Science, Ekiti State University, Ado Ekiti, Ekiti State Nigeria.
authors: Hannah Opeyemi
authors: HO
authors: Ajibola
authors: Department of Science Laboratory Technology, Faculty of Science, Ekiti State University, Ado Ekiti, Ekiti State Nigeria.
authors: Deborah Oluwaseyi
authors: DO
authors: Makanjuola
authors: Department of Virology, College of Medicine, University of Ibadan, Ibadan, Oyo State Nigeria ; WHO National Polio Laboratory, University of Ibadan, Ibadan, Oyo State Nigeria.
authors: Johnson Adekunle
authors: JA
authors: Adeniji
keywords: HBV; Immune escape mutant; Nigeria; Pregnant women; Vaccine escape mutant