PurposeOccult 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.MethodsPlasma 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.ResultsTwenty 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.ConclusionsFindings 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12981-017-0136-0) contains supplementary material, which is available to authorized users.

Zika virus (ZIKV) 3 is an enveloped, single-stranded, positive-sense RNA virus of the Flaviviridae family that has emerged as a public health threat because of its global transmission and link to microcephaly. Currently there is no vaccine for this virus. Conversion of cholesterol to 25-hydroxycholesterol by cholesterol 25-hydroxylase (CH25H) has been shown to have broad antiviral properties. However, the molecular basis of induction of CH25H in humans is not known. Elucidation of signaling and transcriptional events for induction of CH25H expression is critical for designing therapeutic antiviral agents. In this study, we show that CH25H is induced by ZIKV infection or Toll-like receptor stimulation. Interestingly, CH25H is induced by pro-inflammatory cytokines, including IL-1␤, tumor necrosis factor ␣, and IL-6, and this induction depends on the STAT1 transcription factor. Additionally, we observed that cAMP-dependent transcription factor (ATF3) weakly binds to the CH25H promoter, suggesting cooperation with STAT1. However, ZIKV-induced CH25H was independent of type I interferon. These findings provide important information for understanding how the Zika virus induces innate inflammatory responses and promotes the expression of anti-viral CH25H protein.

BackgroundHBV and HIV share similar transmission routes. Concurrent infection with the two viruses usually results in more severe and progressive liver disease, and a higher incidence of cirrhosis, liver cancer and mortality. Further, this co-infection may lead to cross-resistance between HIV and HBV drugs and increased liver injury, either due to direct hepatotoxicity or drug-related immune-reconstitution hepatitis. These challenges necessitate continuous surveillance for HBV among HIV infected individuals to guide patient management. We conducted this study to understand the serologic and genotypic characteristics of HBV among HIV/HBV infected patients in South West and Littoral Regions of Cameroon.MethodsPlasma samples were screened for HBsAg, HBeAg, Anti-HBs and anti-HBc using ELISA followed by DNA extraction from all HBsAg positive samples. A 366 bp region covering the overlapping surface/polymerase gene was amplified by a nested PCR and the product sequenced using Big Dye sequencing chemistry. The resulting sequences were then analyzed for genotypes and both escape and drug resistance mutations.ResultsOf the 455 samples in this study, 25.5 % (n = 116) were HBsAg positive and 46 of these had their DNA successfully amplified. Genotype E was found in 32 samples (69.6 %) and genotype A in the rest of the samples. Escape mutations associated with failure of diagnosis (Y100C, R122K and Q129H) and with vaccine escape (Q129R and T131N) were detected in varying frequencies in the population. Polymerase mutations implicated in resistance to lamivudine and other ʟ-nucleoside analogues were detected in seven patients (15.2 %), while all the samples lacked mutations associated with resistance to adefovir and tenofovir.ConclusionsThese findings suggest the endemicity of HBV and the predominance of genotypes A and E in the study population. Also, drug resistance findings support the use of tenofovir based ART regimens among HIV/HBV co-infected persons. There is need for continuous HBV screening and monitoring in HIV infected individuals in these regions.

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