Detection of uncommon G3P[3] rotavirus A (RVA) strain in rat possessing a human RVA-like VP6 and a novel NSP2 genotype.

Rotavirus is one of the leading causes of acute gastroenteritis in infants and young children. RVAs infect not only humans but also a wide range of mammals including rats, which represent a reservoir of several other zoonotic pathogens. Due to the segmented nature of the RVA genome, animal RVA strains can easily adapt to the human host by reassortment with co-infecting human viruses. This study aims to detect and characterize RVA in the intestinal content of Italian sinantropic rats (Rattus rattus). Out of 40 samples examined following molecular approach, one resulted positive for RVA. The molecular characterization of VP1-4, 6 and 7, and NSP1-5 genes by sequencing revealed the genomic constellation G3-P[3]-I1-R11-C11-M10-A22-N18-T14-E18-H13. This uncommon genomic combination includes: the VP1-4,VP7, the NSP1, 3, 4 and 5 gene segments, closely related to those of RVA from rodents, the N18 novel genotype established for the NSP2 gene segment and the human Wa-like VP6 gene, suggesting interspecies reassortment.

Hospital-acquired rotavirus and norovirus acute gastroenteritis in a pediatric unit, in 2014-2015.

The occurrence of hospital-acquired acute gastroenteritis (AGE) is a major concern for public health. RotavirusA (RVA) and norovirus (NoV) are common causes of viral AGE in the pediatric population, and their role in nosocomial infections has been proven, remaining poorly investigated. To investigate RVA and NoV in hospital-acquired AGE, 55 stool samples from children with nosocomial AGE were collected between May 2014 and May 2015. To evaluate virus spreading routes, 51 environmental swabs were collected from staff and patients' rooms. Stools were tested for both RVA and NoV RNA by reverse-transcription-PCR. Nucleotide sequencing and phylogenetic analysis were performed to characterize the viruses. Forty-seven of 55 cases analyzed resulted positive for RVA. The predominant genotype was G4P[8] (18/55) followed by G1P[8] (14/55). Mixed RVA infections were also detected (7/55). Twenty-two samples were positive for NoV, and GII.4 was revealed to be the predominant genotype. Seventeen samples were positive for both RVA and NoV. This study aimed to evaluate the burden of norovirus and rotavirus nosocomial AGE, contributing to identify the environment source of infections and to activate effective strategies for intervention. The reduction in nosocomial AGE cases is an important aspect, considered the worsened disease course in transplant, cancer, and intensive care unit inpatients.

Molecular characterization of two rare human G8P[14] rotavirus strains, detected in Italy in 2012.

Since 2007, the Italian Rotavirus Surveillance Program (RotaNet-Italy) has monitored the diversity and distribution of genotypes identified in children hospitalized with rotavirus acute gastroenteritis. We report the genomic characterization of two rare human G8P[14] rotavirus strains, identified in two children hospitalized with acute gastroenteritis in the southern Italian region of Apulia during rotavirus strain surveillance in 2012. Both strains showed a G8-P[14]-I2-R2-C2-M2-A11-N2-T6-E2-H3 genomic constellation (DS-1-like genomic background). Phylogenetic analysis of each genome segment revealed a mixed configuration of genes of animal and zoonotic human origin, indicating that genetic reassortment events generated these unusual human strains. Eight out of 11 genes (VP1, VP2, VP3, VP6, VP7, NSP3, NSP4 and NSP5) of the Italian G8P[14] strains exhibited close identity with a Spanish sheep strain, whereas the remaining genes (VP4, NSP1 and NSP2) were more closely related to human strains. The amino acid sequences of the antigenic regions of outer capsid proteins VP4 and VP7 were compared with vaccine and field strains, showing high conservation between the amino acid sequences of Apulia G8P[14] strains and human and animal strains bearing G8 and/or P[14] proteins, and revealing many substitutions with respect to the RotaTeq™ and Rotarix™ vaccine strains. Conversely, the amino acid analysis of the four antigenic sites of VP6 revealed a high degree of conservation between the two Apulia strains and the human and animal strains analyzed. These results reinforce the potential role of interspecies transmission and reassortment in generating novel rotavirus strains that might not be fully contrasted by current vaccines.

Genetic variability of VP7, VP4, VP6 and NSP4 genes of common human G1P[8] rotavirus strains circulating in Italy between 2010 and 2014.

Group A rotaviruses (RVA) are the leading cause of acute gastroenteritis (AGE) in young children worldwide. The RVA outer capsid layer is composed of the VP7 and VP4 proteins. The VP7 (G-type) and VP4 (P-type) genotypes are the basis for the binary RVA nomenclature. At least 27 G-types and 37 P-types of RVA are currently known, but most of human infections are related to the five major genotypes G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]. Every year G1P[8] strains cause approximately 50% of all symptomatic RVA infections reported in children in Italy. Fifteen G1P[8] RVA strains identified in different areas of Italy between 2010 and 2014 were selected. Strains were subjected to nucleotide sequencing of the VP7, VP4, VP6 and NSP4 genes to investigate their genetic variability with respect to geographic area and date of detection. Phylogenetic analyses showed that the 15 G1P[8] RVA strains belonged to two different lineages for both the VP7 and NSP4 genes, and showed some intra-lineage diversity in VP4 and VP6 genes. Similarities between strains correlated by either area or date of detection were also evaluated. The results obtained by phylogenetic analyses were confirmed analyzing the deduced amino acid sequences of the VP7, VP4, VP6 and NSP4 proteins of the G1P[8] RVA strains, detecting several substitutions in all proteins. The genetic variability observed between common G1P[8] RVAs highlights the constant evolution of the RVA genome through random point mutations (genetic drift) and intra-genotype reassortment (genetic shift). The evolution and diversity of the G1 RVA strains observed in this study can be related to the naturally acquired herd immunity, which represents the main mechanism of selective pressure in Italy, where mass anti-rotavirus vaccination was missing during the years of the study.

Removal of enteric viruses and Escherichia coli from municipal treated effluent by zebra mussels.

Dreissena polymorpha is a widespread filter-feeder species, resistant to a broad range of environmental conditions and different types of pollutants,which has recently colonized Italian freshwaters. Although widely used to monitor pollution in freshwater environments, this species is also an important food source for some fish and water birds. It can also be used to concentrate or remove particulate organic matter to interrupt avian-to-human transmission of pollutants and control health risks for animals and humans. In this study, the accumulation/inactivation in D. polymorpha of human health-related spiked enteric viruses was described. The removal of endogenous Escherichia coli, the classical indicator of fecal contamination,was tested as well.Our preliminary lab-scale results demonstrate that zebra mussels can reduce significantly poliovirus titer after 24 h and rotavirus titer after 8 h. E. coli counts were also reduced in the presence of zebra mussels by about 1.5 log after 4 h and nearly completely after 24 h. The fate of the two enteric viruses after concentration by zebra mussels was also investigated after mechanical disruption of the tissues. To our knowledge, the accumulation from water and inactivation of human health-related enteric viruses by zebra mussels has never been reported.

Genomic characterization of uncommon human G3P[6] rotavirus strains causing diarrhea in children in Italy in 2009.

Group A rotaviruses (RVA) are the leading cause of acute gastroenteritis in young children, causing up to 450,000 deaths worldwide, mostly in developing countries. Most of RVA human infections in developed countries are related to five major G/P combinations: G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]. During the surveillance activity of RotaNet-Italy, three uncommon G3P[6] RVA strains, designated as RVA/Human-wt/ITA/NA01/2009/G3P[6], RVA/Human-wt/ITA/NA06/2009/G3P[6], and RVA/Human-wt/ITA/NA19/2009/G3P[6], were identified in the stools of children with diarrhea hospitalized in Southern Italy in 2009. Samples NA01, NA06 and NA19 were characterized as genotype G3P[6]. To investigate the three strains further, partial sequencing of the eleven genomic segments was performed. RVA strains NA01, NA06 and NA19 were found to share the rare genotype constellation: G3-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2, which had not been reported previously in continental Italy. The phylogenetic analysis of the eleven genomic segments showed no evidence of zoonosis or inter-species reassortment at the origin of the Italian G3P[6] strains, indicating that they possessed DS-1-like genomic constellations similar to those detected previously in human cases in Africa and Europe. The analysis of the hypervariable regions of VP7 and VP4 (VP8*) revealed high amino acid identity between the Italian G3P[6] RVA strains involved in this study.

Evolution of human G4P[8] group A rotavirus strains circulating in Italy in 2013.

Group A rotaviruses (RVA) are the leading cause of acute gastroenteritis in young (<5 years of age) children, causing up to 450.000 deaths worldwide, mostly in developing countries. VP7 (G-type) and VP4 (P-type) genotypes are the basis for the binary RVA classification. Although at least 27 G-types and 37 P-types of rotavirus are presently known, most RVA infections in humans worldwide are associated with the five major G/P combinations G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]. During RVA gastroenteritis surveillance in Italy, a total of 1112 samples collected from children hospitalized with acute gastroenteritis in 2013 were RVA positive and were genotyped following standardized protocols from the EuroRotaNet. Most strains analyzed belonged to the five major human genotypes. Among these common strains, 22 G4P[8] RVA strains from different Italian regions were subjected to nucleotide sequencing of their VP4, VP6, VP7 and NSP4 genes to investigate their evolution. The phylogenetic analysis showed that the Italian strains belonged to lineage G4-I for VP7 and to lineage P[8]-III for VP4, in line with the modern G4P[8] RVA strains detected in children worldwide. The phylogenetic trees revealed high degrees of nucleotide identity between the RVA strains involved in this study and G4P[8] strains detected previously in Europe, Asia and Africa, but also demonstrated at least three separate evolution clusters within the same lineage. Based on the amino acid sequences deduced for their hypervariable regions, both the VP7 and VP8* proteins of the Italian G4P[8] RVA strains presented amino acid substitutions near known neutralizing epitopes.

Genomic characterization and molecular investigation of VP7 epitopes of uncommon G10P[8] group A rotavirus strains detected in Italy in 2009.

Rotavirus strains with the uncommon genotype G10 have been detected sporadically in cases of acute gastroenteritis in humans and are thought to be transmitted zoonotically. During 2009, 10 G10P[8] rotavirus strains were detected in the stools of children hospitalized with acute diarrhoea in several paediatric hospitals in Italy. The phylogenetic analysis of the VP7 gene of the Italian G10P[8] strains analysed revealed nucleotide identities ranging from 94 to 99 %. Molecular characterization of the 11 genomic segments was performed for one of the G10 strains, which displayed a complete genomic constellation 1 for the non-G genes. The analysis of the deduced amino acid sequences of the G10 VP7 epitopes revealed low amino acid identity with common human strains of different G genotype and with the VP7 proteins included in both anti-rotavirus commercial vaccines (Rotarix and RotaTeq). Amongst the common G genotypes, the VP7 amino acid sequence of the G10 strains showed a high similarity with sequences from G9 strains. A hydrophobic cluster analysis (HCA) of the VP7 protein including aa 20-298 was performed for the G10 Italian sequences in comparison with the major human group A rotavirus G genotypes. The HCA analysis confirmed the findings obtained previously by amino acid analysis of the VP7 epitopes, detecting a genotype-specific pattern of hydrophobicity in the hypervariable regions of the major outer capsid protein.

Rotavirus genotypes in sewage treatment plants and in children hospitalized with acute diarrhea in Italy in 2010 and 2011.

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. Thirty-two 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.

Detection of rare G3P[19] group A rotavirus in human patient, Italy.

Infection with a rare G3P[19] rotavirus A strain was identified in an immunosuppressed patient in Italy. The strain showed a P[19] viral protein 4 gene and a complete AU-1-like genomic constellation. Phylogenetic analyses showed high nucleotide identity between this strain and G3P[19] rotavirus A strains from Asia, indicating possible reassortment events.

Investigation and control of a Norovirus outbreak of probable waterborne transmission through a municipal groundwater system.

During March 2011 an outbreak of gastroenteritis occurred in Santo Stefano di Quisquina, Agrigento, Sicily, Italy. Within two weeks 156 cases were identified among the 4,965 people living in the municipality. An epidemiological investigation was conducted to characterize the outbreak and target the control measures. A case was defined as a person developing diarrhea or vomiting during February 27-March 13, 2011. Stool specimens were collected from 12 cases. Norovirus (NoV) genotype GII.4 variant New Orleans 2009 was identified in stool samples from 11 of 12 cases tested (91.7%). Epidemiological investigations suggested a possible association with municipal drinking water consumption. Water samples from the public water system were tested for NoV and a variety of genotypes were detected during the first 3 months of surveillance, including GII.4 strains belonging to different variants from that involved in the gastroenteritis outbreak. Contamination of the well and springs supplying the public water network was eventually thought to be the source of the NoV contamination.

Full-length genomic analysis of porcine rotavirus strains isolated from pigs with diarrhea in Northern Italy.

Group A rotaviruses (RVA) cause acute dehydrating diarrhea in young of man and many animal species, including pigs. Swine RVA has an important economic impact on the farming industry, and pigs represent a potential reservoir for zoonotic transmission of RVA to humans. To investigate the genetic diversity of porcine RVA strains in Italy and identify their possible zoonotic characteristics, 25 RVA-positive feces were collected from diarrheic pigs in Northern Italy, in 2009-2010; all viral strains were characterized by G and P genotyping RT-PCR. Three samples were selected for full genome sequencing. Sequencing of the NSP3 genes of all samples was also performed. Rotavirus diagnosis was carried out by ELISA and electron microscopy. RT-PCR and Sanger sequencing were performed in a one-tube format, using primer sets specific for each of the 11 genome segments. Analysis of the G (VP7) and P (VP4) genotypes showed that all strains identified were typical porcine RVAs (G4, G5, G9; P[6], P[13], P[23]). Full-length genome sequencing was performed on selected G9 isolates. Most segments belonged to the genotype constellation 1 (Wa-like), which is shared by most human RVA strains, but gene types such as I5 (VP6) and A8 (NSP1), which are typical of porcine and rare among human RVAs, were also detected. We identified RVA strains showing the T7 genotype, an NSP3 gene type that was previously reported in unusual strains of possible porcine or bovine origin from children with diarrhea. Recent reports suggested that G9 RVA may have been introduced from swine to human populations involving gene reassortment events. The observation that some of the RVA genotypes from swine in Italy were similar to viruses characterized in children underlines the importance of animal RVA surveillance, to clarify and monitor the role of animals as genetic reservoirs of emerging RVA strains pathogenic for humans.

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. Forty-two samples obtained by the RotaNet-Italia (2.6%) were from adolescents or adults (10-89 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.

Detection of unusual G6 rotavirus strains in Italian children with diarrhoea during the 2011 surveillance season.

Two rare G6 rotavirus A (RVA) strains, designated as RVA/human-wt/ITA/CEC06/2011/G6P[6] and RVA/human-wt/ITA/PG05/2011/G6P[9], were identified in stool specimens from children hospitalized in Central Italy. After PCR genotyping, the samples CEC06 and PG05 gave G-UD-P[6] and G-UD-P[9] genotypes, respectively. To determine the G-type and to characterize further the two strains, sequencing of 8 of the 11 genomic segments was performed. CEC06 and PG05 strains were found to possess unusual genotype constellations: G6-P[6]-I2-A2-N2-T2-E2-H2 and G6-P[9]-I2-A3-N2-T3-E3-H3, respectively. This study reports the first detection of rare G6P[6] and G6P[9] RVA strains in peninsular Italy. Phylogenetic analysis of VP4 (VP8*), VP7, VP6, and NSP1-5 showed no evidence of zoonosis or inter-species reassortment, revealing for both strains constellations previously associated to human cases.

Rare types of rotaviruses isolated from children with acute gastroenteritis in Patras, Greece.

BACKGROUND: Acute diarrhea remains a major public health issue worldwide, with gastroenteritis agents associated with a high morbidity, especially in infants and young children. A 1-year study (2009-2010) of rotavirus (RV)-caused pediatric diarrhea was performed on hospitalized children admitted with symptoms of acute diarrhea to the University Hospital of Patras, Greece. METHODS: Twenty-nine fecal samples were investigated for RVs, adenoviruses (AdVs), and enteroviruses (EVs) in an attempt to characterize these enteric viruses, which have been implicated in hospitalized diarrhea. RESULTS: A 44.8% (13/29) incidence of viral infection was reported for the viral targets. Monoinfections accounted for 31% (9/29), while bi-infections accounted for 13.4% (4/29). Sequencing of positive samples allowed identification of RVs G4P[8] (2/29), G9P[8] (1/29), and interestingly of the rare type G12P[8] (2/29). AdV types 1, 2, and 6 were also identified in 4/29, 1/29, and 1/29 of the samples, respectively. Regarding the EVs, EV71 (2/29), coxsackievirus A4 (1/29), echovirus 11 (1/29), and EV96 (1/29) were typed. CONCLUSION: The results of the present study, and specifically the detection of rare RV G12 and EV71 strains, address the need for continuous epidemiological surveys to provide epidemiological pictures of pediatric viral infections circulating in the community.

Prevalence and transmission of hepatitis E virus in domestic swine populations in different European countries.

BACKGROUND: Hepatitis E virus (HEV) genotype 3 and 4 can cause liver disease in human and has its main reservoir in pigs. HEV investigations in pigs worldwide have been performed but there is still a lack of information on the infection dynamics in pig populations. FINDINGS: The HEV transmission dynamics in commercial pig farms in six different European countries was studied. The data collected show prevalence in weaners ranging from 8% to 30%. The average HEV prevalence in growers was between 20% and 44%. The fatteners prevalence ranged between 8% and 73%. Sows prevalence was similar in all countries. Boar faeces were tested for HEV only in Spain and Czech Republic, and the prevalence was 4.3% and 3.5% respectively. The collected data sets were analyzed using a recently developed model to estimate the transmission dynamics of HEV in the different countries confirming that HEV is endemic in pig farms. CONCLUSIONS: This study has been performed using similar detection methods (real time RT-PCR) for all samples and the same model (SIR model) to analyse the data. Furthermore, it describes HEV prevalence and within-herd transmission dynamics in European Countries (EU): Czech Republic, Italy, Portugal, Spain, The Netherlands and United Kingdom, confirming that HEV is circulating in pig farms from weaners to fatteners and that the reproductive number mathematical defined as R0 is in the same range for all countries studied.

Diversity and zoonotic potential of rotaviruses in swine and cattle across Europe.

Group A rotaviruses can infect both humans and animals. Individual rotavirus strains can occasionally cross species barriers and might hereby contribute to the emergence of new genotypes in heterologous hosts. The incidence and impact of zoonotic rotavirus are not well defined, and one reason for this is a lack of data about strains circulating in suspected reservoir animal hosts. In this study we report the incidence, genetic diversity, and molecular epidemiology of rotaviruses detected in domestic cattle and swine in 6 European countries. From 2003 to 2007, 1101 and more than 2000 faecal specimens were collected from swine and cattle, both healthy and diarrhoeic, and tested for rotaviruses. Viruses from positive stools were genotyped and a subset of strains was characterized by nucleotide sequencing and phylogenetic analysis of the VP7 (G) and VP4 (P) genes. Rotaviruses were detected in 43% of bovine samples and in 14% of porcine samples. In cattle, 10 different combinations of G and P types were identified and the most common strains were G6P[11] and G6P[5]. In swine, the number of identified G-P combinations was higher (n=21), however, no single combination was predominant across Europe. Newly described genotype specificities, P[27] and P[32], were identified in swine. When compared at the nucleotide sequence level, the identified porcine rotavirus strains and contemporary human strains grouped together phylogenetically, whereas bovine rotavirus strains formed separate clades. These data demonstrate large genetic diversity of porcine and bovine rotavirus strains across Europe, and suggest that livestock herds may serve as potential reservoirs for human infections.

Virus hazards from food, water and other contaminated environments.

Numerous viruses of human or animal origin can spread in the environment and infect people via water and food, mostly through ingestion and occasionally through skin contact. These viruses are released into the environment by various routes including water run-offs and aerosols. Furthermore, zoonotic viruses may infect humans exposed to contaminated surface waters. Foodstuffs of animal origin can be contaminated, and their consumption may cause human infection if the viruses are not inactivated during food processing. Molecular epidemiology and surveillance of environmental samples are necessary to elucidate the public health hazards associated with exposure to environmental viruses. Whereas monitoring of viral nucleic acids by PCR methods is relatively straightforward and well documented, detection of infectious virus particles is technically more demanding and not always possible (e.g. human norovirus or hepatitis E virus). The human pathogenic viruses that are most relevant in this context are nonenveloped and belong to the families of the Caliciviridae, Adenoviridae, Hepeviridae, Picornaviridae and Reoviridae. Sampling methods and strategies, first-choice detection methods and evaluation criteria are reviewed.

Uniformity of rotavirus strain nomenclature proposed by the Rotavirus Classification Working Group (RCWG).

In April 2008, a nucleotide-sequence-based, complete genome classification system was developed for group A rotaviruses (RVs). This system assigns a specific genotype to each of the 11 genome segments of a particular RV strain according to established nucleotide percent cutoff values. Using this approach, the genome of individual RV strains are given the complete descriptor of Gx-P[x]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx. The Rotavirus Classification Working Group (RCWG) was formed by scientists in the field to maintain, evaluate and develop the RV genotype classification system, in particular to aid in the designation of new genotypes. Since its conception, the group has ratified 51 new genotypes: as of April 2011, new genotypes for VP7 (G20-G27), VP4 (P[28]-P[35]), VP6 (I12-I16), VP1 (R5-R9), VP2 (C6-C9), VP3 (M7-M8), NSP1 (A15-A16), NSP2 (N6-N9), NSP3 (T8-T12), NSP4 (E12-E14) and NSP5/6 (H7-H11) have been defined for RV strains recovered from humans, cows, pigs, horses, mice, South American camelids (guanaco), chickens, turkeys, pheasants, bats and a sugar glider. With increasing numbers of complete RV genome sequences becoming available, a standardized RV strain nomenclature system is needed, and the RCWG proposes that individual RV strains are named as follows: RV group/species of origin/country of identification/common name/year of identification/G- and P-type. In collaboration with the National Center for Biotechnology Information (NCBI), the RCWG is also working on developing a RV-specific resource for the deposition of nucleotide sequences. This resource will provide useful information regarding RV strains, including, but not limited to, the individual gene genotypes and epidemiological and clinical information. Together, the proposed nomenclature system and the NCBI RV resource will offer highly useful tools for investigators to search for, retrieve, and analyze the ever-growing volume of RV genomic data.

Nosocomial Rotavirus Gastroenteritis in pediatric patients: a multi-center prospective cohort study.

BACKGROUND: Few data are available on the incidence of nosocomial Rotavirus infections (NRVI) in pediatric hospitals and on their economic impact. The goals of this study were: to evaluate the incidence of NRVI in various Italian pediatric wards during the course of two peak RV seasons; to investigate possible risk factors for NRVI; to estimate the costs caused by NRVI. METHODS: prospective cohort study. POPULATION: All the children under 30 months of age who were admitted without any symptom or diagnosis of gastroenteritis in the pediatric hospitals of Florence, Naples, Brescia and Ancona, Italy, during the winter-spring periods 2006-2007 and 2007-2008. Serial RV rapid tests and clinical monitoring were carried out on the cohort. Telephone interviews were performed from 3 to 5 days after discharge. RESULTS: 520 out of 608 children completed the study (85.6%). The overall incidence of NRVI was 5.3% (CI95% 3.6-7.5), (7.9 per 1,000 days of hospital stay, CI 95% 5.3-11.3). The average duration of hospital stay was significantly longer for children who had NRVI (8.1 days, SD 5.4) than for non-infected children (6.4 days, SD 5.8, difference 1.7 days, p = 0.004). The risk of contracting NRVI increased significantly if the child stayed in hospital more than 5 days, RR = 2.8 (CI95% 1.3-6), p = 0.006. In Italy the costs caused by NRVI can be estimated at 8,019,155.44 Euro per year. 2.7% of the children hospitalized with no gastroenteritis symptoms tested positive for RV. CONCLUSIONS: Our study showed a relevant incidence of NRVI, which can increase the length of the children's stay in hospital. Limiting the number of nosocomial RV infections is important to improve patients' safety as well as to avoid additional health costs.