Viral agents of gastroenteritis and their correlation with clinical symptoms in rotavirus-vaccinated children

Background and objectives: Enteric viral infections are among the leading causes of gastroenteritis in children up to five years of age worldwide. This study was aimed to determine the disease severity, incidence, and molecular genotyping of rotaviruses, noroviruses, astroviruses, and enteric adenoviruses as gastroenteritis agents among children up to five years old. Materials and methods: Gastroenteritis severity was determined by using the Ruuska and Vesikari score, whereas the incidence of enteric infections and their genotyping were determined by reverse transcription-polymerase chain reaction (RT-PCR) and sequence analysis. Results: Rotaviruses were observed to possess the highest incidence with 10% (18/179) of the cases positives; nevertheless, noroviruses had the highest severe gastroenteritis score (13 +/- 3 points). Results indicated that 56% (10/18) of the detected rotavirus strains were genotype G12P[8], 50% (4/8) of noroviruses were GII. 4 and 25% (2/8) were genotype GI.8. Out of the sapovirus positive samples, 30% (2/6) were genotyped as GI.I and GII.I. Sixty percent of the astrovirus strains (3/5) were genotype HAstV-2, and 20% (1/5) were genotype HAstV6. Additionally, one of the adenovirus strains was identified as human mastadenovirus C type 6 specie. Conclusions: The diarrhea severity reduction in children provides evidence that the rotavirus vaccination program in the northwest of Mexico has been successful, even among children infected by the rotavirus emergent strain G12, however, norovirus resulted as the leading severe gastroenteritis-causing agent in children with rotavirus vaccine.