Although the molecular surveillance network RotaNet-Italy provides useful nationwide data on rotaviruses causing severe acute gastroenteritis in children in Italy, scarce information is available on rotavirus circulation in the general Italian population, including adults with mild or asymptomatic infection. We investigated the genotypes of rotaviruses present in urban wastewaters and compared them with those of viral strains from clinical pediatric cases. During 2010 and 2011, 285 sewage samples from 4 Italian cities were tested by reverse transcription-PCRs (RT-PCRs) specific for rotavirus VP7 and VP4 genes. Rotavirus was detected in 172 (60.4%) samples, 26 of which contained multiple rotavirus G (VP7 gene) genotypes, for a total of 198 G types. Thirtytwo samples also contained multiple P (VP4 gene) genotypes, yielding 204 P types in 172 samples. Genotype G1 accounted for 65.6% of rotaviruses typed, followed by genotypes G2 (20.2%), G9 (7.6%), G4 (4.6%), G6 (1.0%), G3 (0.5%), and G26 (0.5%). VP4 genotype P[8] accounted for 75.0% of strains, genotype P[4] accounted for 23.0% of strains, and the uncommon genotypes P[6], P[9], P[14], and P[19] accounted for 2.0% of strains altogether. These rotavirus genotypes were also found in pediatric patients hospitalized in the same areas and years but in different proportions. Specifically, genotypes G2, G9, and P[4] were more prevalent in sewage samples than among samples from patients, which suggests either a larger circulation of the latter strains through the general population not requiring medical care or their greater survival in wastewaters. A high level of nucleotide identity in the G1, G2, and G6 VP7 sequences was observed between strains from the environment and those from patients.

Rotavirus gastroenteritis is associated mainly with the five genotypes G1,3,4,9P[8] and G2P[4] that are common worldwide, but emerging strains including G6, G8, and G12 are also reported sporadically. G12P[8] rotavirus was observed unexpectedly to spread in a limited area of Italy during the rotavirus surveillance season 2012-2013. All strains were genotyped for VP7 and VP4 and subjected to phylogenetic analysis. Amino acid sequences of antigenic regions were compared with vaccine and field strains. G12P[8] strains were detected in the stools of 52 of 69 (75%) children infected with rotavirus in the central Italian region of Umbria. All G12 strains belonged to lineage III, and presented the P[8] genotype. Sequence analysis showed close nucleotide identity of both VP4 and VP7 genes among Umbria G12P[8] strains. The VP7 gene was also similar to other G12 strains circulating in different years and countries, and the VP4 gene was closely related to other local and global P[8] strains possessing different G-types. Overall findings suggest either the introduction and evolution of a G12 VP7 gene into the local Wa-like rotavirus population or the spreading of a strain novel for the area. Comparison of the VP8* and VP7 antigenic regions showed high conservation between the amino acid sequences of Umbria G12P[8] strains, and revealed various substitutions in the VP8* antigenic regions between the Italian G12P[8] strains and RotaTeq™ and Rotarix™ vaccine strains. The sudden and unexpected emergence of G12P[8] rotavirus confirms that these strains have the potential to become a sixth common genotype across the world.

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Within the initiatives for poliomyelitis eradication by WHO, Italy activated an environmental surveillance (ES) in 2005. ES complements clinical Acute Flaccid Paralysis (AFP) surveillance for possible polio cases, detects poliovirus circulation in environmental sewage, and is used to monitor transmission in communities. In addition to polioviruses, the analyses comprised: (i) the monitoring of the presence of non-polio enteroviruses in sewage samples and (ii) the temporal and geographical distribution of the detected viruses. From 2009 to 2015, 2880 sewage samples were collected from eight cities participating in the surveillance. Overall, 1479 samples resulted positive for enteroviruses. No wild-type polioviruses were found, although four Sabin-like polioviruses were detected. The low degree of mutation found in the genomes of these four isolates suggests that these viruses have had a limited circulation in the population. All non-polio enteroviruses belonged to species B and the most frequent serotype was CV-B5, followed by CV-B4, E-11, E-6, E-7, CV-B3, and CV-B2. Variations in the frequency of different serotypes were also observed in different seasons and/or Italian areas. Environmental surveillance in Italy, as part of the 'WHO global polio eradication program', is a powerful tool to augment the polio surveillance and to investigate the silent circulation or the re-emergence of enteroviruses in the population.

Group A rotaviruses (RVA) are the leading cause of acute gastroenteritis (AGE) in children worldwide and cause up to 455,000 deaths annually, mostly in developing countries. During 2013, 66 RVAs from children with AGE admitted to four Nigerian hospitals were investigated. The G3P[6], G1P[8] and G2P[4] genotypes predominated. The VP7 and/or VP4 genes of 18 G3P[6]/[8]/[4], six G2P[4], three G12P[8]/[4], and two G1P[8] RVA strains were sequenced. The G3P[6] strains belonged to lineage G3-III and were different from G3 strains widespread in Asia. Phylogenetic analysis revealed substantial sequence conservation, suggesting continuing evolution and genomic reassortment but no zoonotic RVA transmission from animals.