Molecular epidemiology of human astrovirus and adenovirus serotypes 40/41 strains related to acute diarrhea in Tunisian children

Human astrovirus (AstV) and adenovirus types 40 and 41 (AdV 40/41) are responsible for epidemic and endemic acute gastroenteritis in children and adults. The present study was designed to evaluate the prevalence and genetic diversity of enteric viruses in children in Tunisia. A total of 788 fecal samples were collected during a 4-year period in the region of Monastir, from children under 12 years old, hospitalized or presenting in dispensaries with symptoms of acute gastroenteritis. AstV and AdV40/41 were detected by immunoenzymatic methods and confirmed by PCR/RT-PCR and sequence analysis. Phylogenetic analyses were performed for nucleotide homology with reference strains. AstV and AdV40/41 were characterized as a causative agent in 28 (3.6%) and 18 (2.3%) of the fecal samples, respectively. Phylogenetic analysis showed that the AstVs belonged to the serotypes 3 (n = 4; 14.3%) and 1 (n = 24; 85.7%), and the enteric AdVs to the serotypes 40 (n = 1; 5.6%) and 41 (n = 17; 94.4%). This is the first report that describes the molecular epidemiology of AstV and AdV40/41 in Tunisian children. Their respective detection rate was very low, far below that of rotavirus and norovirus. The genetic diversity among these two viruses is relatively limited and varies depending on the area.