Molecular Characterisation of Human Respiratory Adeno Viruses in Uganda

Abstract

Human adenoviruses (HAdV) are a diverse group of viruses causing a broad range of infections of the respiratory, urogenital and gastrointestinal tracts, and keratoconjunctivitis. There are seven species of human adenoviruses with over 51 serotypes and 69 genotypes which may contain multiple genetic variants. This study characterised the genotypes of human respiratory adenoviruses and associated factors in samples collected from selected hospitals in Uganda. A total of 2,298 nasopharyngeal samples were collected from patients seeking health care at tertiary hospitals for influenza-like illness. They were screened by Polymerase Chain Reaction (PCR) to determine the prevalence of HAdV. HAdV was isolated in A549 cell lines and the Hexon gene from the HAdV isolates was sequenced by sanger sequencing method using the BigDye Terminator v3.1. Of the 2,298 samples tested, 225 (9.8%) were adenovirus positive by PCR. Age and HAdV infection were found to be significantly associated (p = 0.028) with 98% (220/225) of the positives in children below 6 years and none in adults above 25 years of age. The sequenced isolates belonged to species HAdV B and HAdV C with most isolates identified as genotype B3. The results showed a high prevalence and HAdV genetic diversity in respiratory HAdV circulating in Ugandan population. Children aged between 0 to 5 years were more likely to get infected with HAdV than other age groups. Deeper genomic characterization based on whole genome sequencing is necessary to further elucidate possible transmission and impact of current adeno-vectored vaccines in Africa.