Occult hepatitis B viral infection among blood donors in South–Eastern Nigeria

Hepatitis B virus infection is endemic in many parts of sub-Saharan Africa including Nigeria. Occult hepatitis B virus infection (OBI) is a challenging clinical problem characterized by the absence of Hepatitis B surface Antigen (HBsAg) and low viral DNA load. We aimed at determining the prevalence of OBI among repeat blood donors in Abakaliki, south-eastern Nigeria. Of 113 informed consented repeat blood donors enrolled into the study, 12 donors (10.6%) tested positive to both serological HBsAg screening, anti-HBc total and hepatitis B virus (HBV) DNA Nested PCR tests. One donor (0.9%) tested HBsAg positive, anti-HBC positive but Nested PCR negative. All donors were negative for HIV 1 and 2 and HCV infections. Of the 100 HbsAg negative repeat blood donors, 8.0% (eight donors) were HBV DNA positive by nested PCR method and anti-HBc total positive by ELISA. The median viral load, determined by real time PCR-Taqman chemistry, in the OBI blood samples was 51 IU/ml compared to 228 IU/ml of the HBsAg screen positive donors. The observed OBI prevalence of 8.0% corroborated with high endemicity of HBV infection in Abakaliki. We therefore recommend routine HBV DNA testing by real time PCR method on all sero-negative blood donations in Abakaliki and for a similar policy to be evaluated across the sub-Saharan Africa.