Gachara, GeorgeMagoro, TshifhiwaMavhandu, LufunoLum, EmmaculateKimbi, Helen K.Ndip, Roland N.Bessong, Pascal O.2018-04-122018-04-122017AIDS Research and Therapy (2017),14:11. DOI 10.1186/s12981-017-0136-0http://ir-library.ku.ac.ke/handle/123456789/18306DOI 10.1186/s12981-017-0136-0Purpose: Occult hepatitis B infection (OBI) among HIV positive patients varies widely in different geographic regions. We undertook a study to determine the prevalence of occult hepatitis B infection among HIV infected individuals visiting a health facility in South West Cameroon and characterized occult HBV strains based on sequence analyses. Methods: Plasma samples (n = 337), which previously tested negative for hepatitis B surface antigen (HBsAg), were screened for antibodies against hepatitis B core (anti-HBc) and surface (anti-HBs) antigens followed by DNA extraction. A 366 bp region covering the overlapping surface/polymerase gene of HBV was then amplified in a nested PCR and the amplicons sequenced using Sanger sequencing. The resulting sequences were then analyzed for genotypes and for escape and drug resistance mutations. Results: Twenty samples were HBV DNA positive and were classified as OBI giving a prevalence of 5.9%. Out of these, 9 (45%) were anti-HBs positive, while 10 (52.6%) were anti-HBc positive. Additionally, 2 had dual anti-HBs and anti-HBc reactivity, while 6 had no detectable HBV antibodies. Out of the ten samples that were successfully sequenced, nine were classified as genotype E and one as genotype A. Three sequences possessed mutations associated with lamivudine resistance. We detected a number of mutations within the major hydrophilic region of the surface gene where most immune escape mutations occur. Conclusions: Findings from this study show the presence of hepatitis B in patients without any of the HBV serological markers. Further prospective studies are required to determine the risk factors and markers of OBI. Keywords: Hepatitis B virus, Occult hepatitis B infection, HIV, CameroonenHepatitis B virusOccult hepatitis B infectionHIVCameroonArticle