Serotype Diversity of Respiratory Human Adenoviruses amongst Pediatric Patients from Western Kenya, 2010-2012

Background: Respiratory illnesses are common among pediatric patients in Kenya, and many are attributed to viral causes. However, there is limited knowledge of the diversity of viral etiologies associated with these illnesses. Objective: To characterize respiratory adenoviruses isolates using serological and molecular approaches. Methods: A total of 1,879 samples were collected from symptomatic pediatric patients seeking medical care at New Nyanza Provincial General Hospital during the period of June 2010 to June 2012 and screened for adenoviruses as well as other respiratory viruses. Sixteen respiratory human adenoviruses (HAdVs) were isolated in Hep2 cell culture and characterized them using Immunofluorescence Assay, viral DNA amplification, sequencing and phylogenomics. Results: Phylogenetic characterization of the HAdVs using the hyper variable region 7 of the hexon gene identified HAdV B and C as the major species associated with respiratory infections during the study period. Amongst these, a single B-type and four C-type serotypes were identified.  The serotype distribution consisted of 31% HAdV B7, 25% HAdV C1, 25% HAdV C2, 6% HAdV C5, and 13% HAdV C6. Positive selection was observed in the nucleotide sequences from HAdV B7 and HAdV C5 signaling evolution of these two serotypes. Conclusion: These finding may be useful to policy makers regarding appropriate strain selection for vaccination in Kenya. Keywords: Respiratory Human adenovirus, Kenya, Pediatric, Serotype, Hexon, HVR-7