Molecular analysis of group A rotaviruses detected in adults and adolescents with severe acute gastroenteritis in Italy in 2012

Hospital-based surveillance of acute gastroenteritis caused by rotavirus has produced ample knowledge on the infection in children, whereas little is known on rotavirus infection among adults. The Italian surveillance program RotaNet- Italia collected 1,595 samples from patients admitted to hospital with gastroenteritis in 2012. All patients presented with vomiting, diarrhea, fever, and/or abdominal pain. Fortytwo samples obtained by the RotaNet-Italia (2.6%) were from adolescents or adults (10\u201389 years). The study compared the genotypes and gene sequences of the rotavirus strains identified in adults with strains obtained from children worldwide. All 42 Italian strains were genotyped by the EuroRotaNet RT-nested-PCR protocols, and 12 rotaviruses from patients >13-year-old were subjected to nucleotide sequencing of their VP7 and/or VP4 genes. All strains analyzed belonged to the common human genotypes G1P[8], G2P[4], G4P[8], and G9P[8], except an uncommon G3P[19] genotype detected in a single patient. Phylogenetic analysis of the 12 strains showed that within each genotype they clustered in RVA lineages reported worldwide. The amino acid sequences of the VP7 and the VP8 hypervariable regions were highly conserved between the RVA strains collected from adults and children, in each lineage. Genotyping, phylogenetic analysis, and the study of viral epitopes revealed that rotaviruses circulating in adults in Italy are closely similar to the strains circulating in children, with high nucleotide identity particularly with strains reported in Europe and Asia. The circulation of the same rotavirus strains in both children and adults suggests that adults may contribute to sustain the circulation of rotaviruses through the population

Group A rotavirus surveillance before vaccine introduction in Italy, September 2014 to August 2017

IntroductionGroup A rotaviruses (RVA) are the leading cause of acute gastroenteritis (AGE) in young children, causing ca 250,000 deaths worldwide, mainly in low-income countries. Two proteins, VP7 (glycoprotein, G genotype) and VP4 (protease-sensitive protein, P genotype), are the basis for the binary RVA nomenclature. Although 36 G types and 51 P types are presently known, most RVA infections in humans worldwide are related to five G/P combinations: G1P[8], G2P[4], G3P[8], G4P[8], G9P[8].AimThis study aimed to characterise the RVA strains circulating in Italy in the pre-vaccination era, to define the trends of circulation of genotypes in the Italian paediatric population.MethodsBetween September 2014 and August 2017, after routine screening in hospital by commercial antigen detection kit, 2,202 rotavirus-positive samples were collected in Italy from children hospitalised with AGE; the viruses were genotyped following standard European protocols.ResultsThis 3-year study revealed an overall predominance of the G12P[8] genotype (544 of 2,202 cases; 24.70%), followed by G9P[8] (535/2,202; 24.30%), G1P[8] (459/2,202; 20.84%) and G4P[8] (371/2,202; 16.85%). G2P[4] and G3P[8] genotypes were detected at low rates (3.32% and 3.09%, respectively). Mixed infections accounted for 6.49% of cases (143/2,202), uncommon RVA strains for 0.41% of cases (9/2,202).ConclusionsThe emergence of G12P[8] rotavirus in Italy, as in other countries, marks this genotype as the sixth most common human genotype. Continuous surveillance of RVA strains and monitoring of circulating genotypes are important for a better understanding of rotavirus evolution and genotype distribution, particularly regarding strains that may emerge from reassortment events