Virome of children with acute gastroenteritis identified a novel human adenovirus C type with a chimeric hexon gene

Human Adenovirus species C (HAdV-C) are the most common etiologic agents of respiratory disease. In the present study we characterized the nearly full-length genome of one potential new HAdV-C recombinant strain constitute by Penton and Fiber proteins belonging to type 89 and a chimeric Hexon protein of type 1 and 89. By using viral metagenomics techniques, we screened out, in the state of Tocantins, North Brazil, from 2010 to 2016, 251 fecal samples of children between 0.5 to 2.5-year-old. These children were presenting acute diarrhea not associated with common pathogens (i.e. rotavirus, norovirus). We identified two HAdV-C strains in two distinct patients. Phylogenetic analysis performed using all complete genomes available at GenBank database indicated that one strain (HAdV-C BR-245) belongs to the type 1. The phylogenetic analysis also indicated that the second strain (HAdV-C BR-211) was located at the base of the clade formed by the newly HAdV-C strains type 89. Recombination analysis revealed that strain HAdV-C BR-211is a chimera in which the variable regions of Hexon gene combined HAdV-C1 and HAdV-C89 sequences. Therefore, HAdV-C BR-211 strain possess a genomic backbone of type HAdV-C89 and a unique insertion of HAdV-C1 in the Hexon sequence. Recombination may play an important driving force in HAdV-C diversity and evolution. Studies employing complete genomic sequencing on circulating HAdV-C strains in Brazil are needed to understand the clinical significance of the presented data.