Osuji A^1,, Agbakoba N. R.², Ifeanyichukwu M. O.², Tatfeng M³

Background/Objectives: Occult Hepatitis B virus infection (OBI), characterized by presence of HBV DNA in the absence of HBsAg in individuals has become a challenge to blood safety. The aim of this study is to determine the prevalence rate, HBV serologic markers, viral load and genotypes of occult Hepatitis B Virus infection among blood donors attending Nnamdi Azikiwe University Teaching Hospital and University of Abuja Teaching Hospital Abuja, Nigeria. Materials/Methods: Sera from 212 healthy blood donors (108 and 104 from UATH and NAUTH respectively) were retested for HBsAg, HIV, Syphilis antibodies and anti-HCV using 4^th generation Enzyme Linked Immunosorbent Assay (ELISA). One hundred samples (50 samples from each study site) that were seronegative were examined for the presence of HBV-DNA by conventional Polymerase Chain Reaction (PCR). Viral load was determined on some positive samples by Real Time PCR. Gene sequencing was done to determine HBV genotypes. HBV serological markers prevalence and pattern was determined using ELISA format and HBV 5 Panel assay. Results: Of the 100 seronegative (HBV, HCV, HIV and Syphilis) samples, 14 (14%) were confirmed as OBI. Of the 14 OBI samples, 12 (85.7%) were seropositive for HBV serologic markers and among these, 7 (58.3%) were positive for anti-HBs, 3 (25%) positive for anti-HBc, and 2 (16.7%) positive for both HBsAb and HBcAb (P<0.0001). Three (21.4%) out 14 OBI blood donors were positive for anti-HBc IgM p<0.05. The mean viral load of OBI blood donors was <100 IU/mL. DNA sequencing and Phylogenetic analysis showed that all OBI isolates belong to Genotype E. Conclusion/Recommendations: There is a high prevalence of OBI among blood donors in these two Teaching Hospitals. This study therefore recommends that blood donors in these Hospitals in particular and Nigeria in general be screened for OBI by Nucleic Acid Testing (NAT) and HBV serologic markers.

hepatitis B Virus, OBI, blood donors, HBV Markers, NAT