Rotaviruses In Animals Research Articles

Co-Surveillance of Rotaviruses in Humans and Domestic Animals in Central Uganda Reveals Circulation of Wide Genotype Diversity in the Animals

Rotavirus genotypes are species specific. However, interspecies transmission is reported to result in the emergence of new genotypes. A cross-sectional study of 242 households with 281 cattle, 418 goats, 438 pigs, and 258 humans in Uganda was undertaken between 2013 and 2014. The study aimed to determine the prevalence and genotypes of rotaviruses across co-habiting host species, as well as potential cross-species transmission. Rotavirus infection in humans and animals was determined using NSP3 targeted RT-PCR and ProSpecT Rotavirus ELISA tests, respectively. Genotyping of rotavirus-positive samples was by G- and P-genotype specific primers in nested RT-PCR assays while genotyping of VP4 and VP7 proteins for the non-typeable human positive sample was done by Sanger sequencing. Mixed effect logistic regression was used to determine the factors associated with rotavirus infection in animals. The prevalence of rotavirus was 4.1% (95% CI: 3.0-5.5%) among the domestic animals and 0.8% (95% CI: 0.4-1.5%) in humans. The genotypes in human samples were G9P[8] and P[4]. In animals, six G-genotypes, G3(2.5%), G8(10%), G9(10%), G11(26.8%), G10(35%), and G12(42.5%), and nine P-genotypes, P[1](2.4%), P[4](4.9%), P[5](7.3%), P[6](14.6%), P[7](7.3%), P[8](9.8%), P[9](9.8%), P[10](12.2%), and P[11](17.1%), were identified. Animals aged 2 to 18 months were less likely to have rotavirus infection in comparison with animals below 2 months of age. No inter-host species transmission was identified.

At Least Seven Distinct Rotavirus Genotype Constellations in Bats with Evidence of Reassortment and Zoonotic Transmissions.

Bats host many viruses pathogenic to humans, and increasing evidence suggests that rotavirus A (RVA) also belongs to this list. Rotaviruses cause diarrheal disease in many mammals and birds, and their segmented genomes allow them to reassort and increase their genetic diversity. Eighteen out of 2,142 bat fecal samples (0.8%) collected from Europe, Central America, and Africa were PCR-positive for RVA, and 11 of those were fully characterized using viral metagenomics. Upon contrasting their genomes with publicly available data, at least 7 distinct bat RVA genotype constellations (GCs) were identified, which included evidence of reassortments and 6 novel genotypes. Some of these constellations are spread across the world, whereas others appear to be geographically restricted. Our analyses also suggest that several unusual human and equine RVA strains might be of bat RVA origin, based on their phylogenetic clustering, despite various levels of nucleotide sequence identities between them. Although SA11 is one of the most widely used reference strains for RVA research and forms the backbone of a reverse genetics system, its origin remained enigmatic. Remarkably, the majority of the genotypes of SA11-like strains were shared with Gabonese bat RVAs, suggesting a potential common origin. Overall, our findings suggest an underexplored genetic diversity of RVAs in bats, which is likely only the tip of the iceberg. Increasing contact between humans and bat wildlife will further increase the zoonosis risk, which warrants closer attention to these viruses.IMPORTANCE The increased research on bat coronaviruses after severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) allowed the very rapid identification of SARS-CoV-2. This is an excellent example of the importance of knowing viruses harbored by wildlife in general, and bats in particular, for global preparedness against emerging viral pathogens. The current effort to characterize bat rotavirus strains from 3 continents sheds light on the vast genetic diversity of rotaviruses and also hints at a bat origin for several atypical rotaviruses in humans and animals, implying that zoonoses of bat rotaviruses might occur more frequently than currently realized.

Genetic characterisation of novel G29P[14] and G10P[11] rotavirus strains from African buffalo

We report the first description of rotavirus A strains in African buffalo (Syncerus caffer). Following RNA extraction from stool samples, cDNA was prepared, followed either by sequence-independent amplification and 454 pyrosequencing or direct sequencing on an Illumina MiSeq platform. RVA/Buffalo-wt/ZAF/4426/2002/G29P[14] exhibited a novel G29P[14] combination and an artiodactyl backbone: I2-R2-C2-M2-A11-N2-T6-E2-H3. RVA/Buffalo-wt/ZAF/1442/2007/G10P[11] also exhibited an artiodactyl backbone: I2-R2-C2-M2-A13-N2-T6-E2-H3. Characterisation of these genome constellations indicate that the two buffalo strains are moderately diverse from each other and related to South African bovine RVA strains. The detection of RVA in buffalo contribute to our understanding of the host range of rotavirus in animals.

VP6 gene based RT-PCR for detection of rotavirus associated with diarrhea in bovine calves

The present study was undertaken on VP6 gene based detection of Rotavirus in feces of diarrheic animals. Bovine fecal samples of cattle calves (54) between the age group of 0-3 months were collected from diarrheic animals from organized and unorganized farms in and around Nagpur. Of them 11 (20.37%) out of 54 samples were found positive for bovine rotavirus by latex agglutination test. The positive sample of calf was subjected to VP6 gene based Reverse Transcriptase polymerase chain reaction which yielded amplicon of 379 bp RT-PCR targeting and confirmed Group A rotavirus. VP6 gene base RT-PCR study confirmed the prevalence of group A Rotavirus in animals and can be used as a sensitive and specific assay for the rapid detection of group A Rotavirus in fecal samples.

Rotavirus A in wild and domestic animals from areas with environmental degradation in the Brazilian Amazon.

Acute gastroenteritis is one of the main causes of mortality in humans and young animals. Domestic and mainly wild animals such as bats, small rodents and birds are highly diversified animals in relation to their habitats and ecological niches and are widely distributed geographically in environments of forest fragmentation in some areas of the Amazon, being considered important sources for viruses that affect humans and other animals. Due to the anthropical activities, these animals changed their natural habitat and adapted to urbanized environments, thus representing risks to human and animal health. Although the knowledge of the global diversity of enteric viruses is scarce, there are reports demonstrating the detection of rotavirus in domestic animals and animals of productive systems, such as bovines and pigs. The present study investigated the prevalence of Rotavirus A in 648 fecal samples of different animal species from the northeastern mesoregion of the state of Pará, Brazil, which is characterized as an urbanized area with forest fragments. The fecal specimens were collected from October 2014 to April 2016 and subjected to a Qualitative Real-Time Polymerase Chain Reaction (RT-qPCR), using the NSP3 gene as a target. It was observed that 27.5% (178/648) of the samples presented positive results for RVA, with 178 samples distributed in birds (23.6%), canines (21.35%), chiropterans (17.98%), bovines (14.6%), horses (8.43%), small rodents (6.74%), pigs (3.93%) and felines (3.37%), demonstrating the circulation of RVA in domestic animals and suggesting that such proximity could cause transmissions between different species and the occurrence of rearrangements in the genome of RVA as already described in the literature, associated to the traces of environmental degradation in the studied areas.

Detection of VP6 gene of Rotavirus in Feces of Diarrhoeic calves, kids, lambs, piglets, pups and human infants by Reverse Transcriptase–Polymerase Chain Reaction

The present study was undertaken VP6 gene based detection of Rotavirus in faeces of diarrheic bovine, porcine, caprine, ovine, canine species of animals and human. A total of 280 faecal samples from bovine calves, piglets, kids, lambs, pups and human infants (0-1 yr of age) were screened for the detection of group A Rotavirus by VP6 gene based RT–PCR assay. A Total of 43 (15.35%) samples were found positive for Rotavirus. Maximum 17/50 (34.00%) samples were positive in human infants followed by 7/71 piglets (9.85%), 7/25 lambs (28.00%), 6/26 kids (23.07%), 4/58 bovine calves (6.89%) and 2/50 pups (4.00%). VP6 gene base RT-PCR study confirmed the prevalence of group A Rotavirus in animals and human species. RT–PCR assay can be used as a sensitive and specific assay for the rapid detection of group A Rotavirus in faecal samples.

Higher Expression Level and Lower Toxicity of Genetically Spliced Rotavirus NSP4 in Comparison to the Full-Length Protein in E. coli.

Rotavirus group A (RVA) is recognized as a major cause of severe gastroenteritis in children and new-born animals. Nonstructural protein 4 (NSP4) is responsible for the enterotoxic activity of these viruses in the villus epithelial cells. Amino acids 114-135 of NSP4 are known to form the diarrhea-inducing region of this viral enterotoxin. Therefore, developing an NSP4 lacking the enterotoxin domain could result in the introduction of a new subunit vaccine against rotaviruses in both humans and animals. The aim of this study is the evaluation of rotavirus A NSP4 expression in E. coli expression system before and after removal of the diarrhea-inducing domain, which is the first step towards further immunological studies of the resulting protein. Splicing by overlap extension (SOEing) PCR was used to remove the diarrhea-inducing sequence from the NSP4 cDNA. Both the full-length (FL-NSP4) and the spliced (S-NSP4) cDNA amplicons were cloned into pET-32c and pGEX-6P-2. Expression levels of the recombinant proteins were evaluated in E. coli BL21 (DE3) by Western blot analysis. In addition, the toxicity of pET plasmids bearing the S-NSP4 and FL-NSP4 fragments was investigated by plasmid stability test. For FL-NSP4, protein expression was detected for the strain containing the pGEX:FL-NSP4 plasmid, but not for the strain carrying pET:FL-NSP4. Hourly sampling up to 3 h showed that the protein production decreased by time. In contrast, expression of S-NSP4 was detected for pET:S-NSP4 strain, but not for pGEX:S-NSP4. Plasmid stability test showed that pET:S-NSP4 recombinant plasmid was almost stable, while pET:FL-NSP4 was unstable. This is the first report of production of rotavirus NSP4 lacking the diarrhea-inducing domain (S-NSP4). SNSP4 shows less toxicity in this expression system and potentially could be a promising goal for rotavirus immunological and vaccine studies in the future.

Molecular epidemiology of rotavirus in cats in the United Kingdom.

Rotaviruses are leading causes of gastroenteritis in the young of many species. Molecular epidemiological studies in children suggest that interspecies transmission contributes to rotavirus strain diversity in people. However, population-based studies of rotaviruses in animals are few. We investigated the prevalence, risk factors for infection, and genetic diversity of rotavirus A in a cross-sectional survey of cats housed within 25 rescue catteries across the United Kingdom. Morning litter tray fecal samples were collected during the winter and summer in 2012 from all pens containing kittens and a random sample of those housing adult cats. Group A rotavirus RNA was detected by real-time reverse transcription-PCR, and positive samples were G and P genotyped using nested VP4 and VP7 PCR assays. A total of 1,727 fecal samples were collected from 1,105 pens. Overall, the prevalence of rotavirus was 3.0% (95% confidence interval [CI], 1.2 to 4.9%). Thirteen out of 25 (52%; 95% CI, 31.3 to 72.2%) centers housed at least one rotavirus-positive cat. The prevalence of rotavirus was associated with season (odds ratio, 14.8 [95% CI, 1.1 to 200.4]; P = 0.04) but not age or diarrhea. It was higher during the summer (4.7%; 95% CI, 1.2 to 8.3%) than in winter (0.8%; 95% CI, 0.2 to 1.5%). Asymptomatic epidemics of infection were detected in two centers. G genotypes were characterized for 19 (33.3%) of the 57 rotavirus-positive samples and P genotypes for 36 (59.7%). Two rotavirus genotypes were identified, G3P[9] and G6P[9]. This is the first population-based study of rotavirus in cats and the first report of feline G6P[9], which questions the previous belief that G6P[9] in people is of bovine origin.

Molecular epidemiology of rotavirus in children and animals and characterization of an unusual G10P[15] strain associated with bovine diarrhea in south India

Rotaviruses are enteric pathogens causing acute, watery, dehydrating diarrhea in various host species, including birds and mammals. This study collected data on the disease burden and strain prevalence of Group A rotavirus in animals and humans in Vellore and investigated interspecies transmission by comparison of circulating genotypes. Stool samples from children aged less than 5 years, admitted to the hospital between January 2003 and May 2006 for diarrhea and diarrheal samples from animals that were collected from a veterinary clinic and several dairy farms near Vellore between February 2007 and May 2008 were processed and subjected to RNA extraction and reverse-transcription PCR for genotyping of VP7 and VP4. Of 394 children with diarrhea, 158 (40%) were positive for rotavirus and the common G types identified were G1 (47, 29.7%), G2 (43, 27.2%), G9 (22, 13.9%), G10 (2, 1.2%), G12 (1, 0.6%) and mixed infections (27, 17.8%). The common P types were P[4] accounting for 57 (36%) samples, P[8] 57 (36%), P[11] 3 (1.8%) and P[6] 2 (1.2%). Of 627 animals, 35 (1 bullock, 2 goats, 32 cows) were found to be infected with rotavirus (5.5%). The common G types identified in order of frequency were G6 (17, 48.5%), G2 (10, 28%), G10 (4, 11%), G8 (2, 5.7%) and mixed infections (2, 5.7%). The common P types were P[6] accounting for 16 (46%) samples, P[4] 7 (20%), P[1] 3 (8.5%) and P[8] 3 (8.5%). An unusual P type P[15] was seen in one sample in combination with G10. The finding of G2 infections which are rarely identified in animals implies anthroponotic transmission since this genotype is predominantly associated with infection in humans.

Whole-genome analyses reveals the animal origin of a rotavirus G4P[6] detected in a child with severe diarrhea

Group A rotaviruses are a major cause of severe gastroenteritis in children worldwide. Currently, two rotavirus vaccines are being used in vaccination programs, and one of the factors involved in lower vaccine efficacy is the mismatch among the circulating strains and the vaccine strains. Thus, the emergence of animal strains in the human population could affect the efficacy of vaccination programs. Here we report the presence of a G4P[6] strain in a Paraguayan child presenting acute gastroenteritis in 2009. Genomic analyses revealed that the strain presents a porcine-like genome (G4-P[6]-I1-R1-C1-M1-A8-N1-T7-E1-H1), suggesting a direct animal-to-human transmission. Continuous surveillance of rotaviruses in humans and animals will help us to better understand rotavirus epidemiology and evolution.

Immunogenicity and protective efficacy of yeast extracts containing rotavirus-like particles: A potential veterinary vaccine

Rotavirus is the most common cause of severe diarrhea in many animal species of economic interest. A simple, safe and cost-effective vaccine is required for the control and prevention of rotavirus in animals. In this study, we evaluated the use of Saccharomyces cerevisiae extracts containing rotavirus-like particles (RLP) as a vaccine candidate in an adult mice model. Two doses of 1mg of yeast extract containing rotavirus proteins (between 0.3 and 3μg) resulted in an immunological response capable of reducing the replication of rotavirus after infection. Viral shedding in all mice groups diminished in comparison with the control group when challenged with 100 50% diarrhea doses (DD50) of murine rotavirus strain EDIM. Interestingly, when immunizing intranasally protection against rotavirus infection was observed even when no increase in rotavirus-specific antibody titers was evident, suggesting that cellular responses were responsible of protection. Our results indicate that raw yeast extracts containing rotavirus proteins and RLP are a simple, cost-effective alternative for veterinary vaccines against rotavirus.

Evidences and consequences of extra-intestinal spread of rotaviruses in humans and animals.

Rotavirus is recognized as one of the main diarrheal pathogens in young children and animals. The prevailing central dogma of rotavirus infection states that the infection is confined in the gastrointestinal tract. However, increasing evidences indicate that rotavirus infection is systemic. Clinical case reports of systemic manifestations to rotavirus infection in children has continued to accumulate over the past years. The use of animal models provided pathological and molecular evidences for extra-intestinal infection of rotaviruses. The mechanism correlated with the extra-intestinal spread of rotavirus infection from the intestine is through cell-free and cell-associated viremia. The extent of the extra-intestinal spread of rotavirus infection has not yet been fully elucidated; whether it can only affect a limited number of organs and tissues or capable of involving the body as a whole. Moreover, the influence of systemic rotavirus infections remains to be determined. In this review, combination of previous and new data are outlined to help in better understanding of the extra-intestinal infections of rotaviruses.

Exotic rotaviruses in animals and rotaviruses in exotic animals.

Group A rotaviruses (RVA) are a major cause of viral diarrhea in the young of mammals and birds. RVA strains with certain genotype constellations or VP7-VP4 (G-P) genotype combinations are commonly found in a particular host species, whilst unusual or exotic RVAs have also been reported. In most cases, these exotic rotaviruses are derived from RVA strains common to other host species, possibly through interspecies transmission coupled with reassortment events, whilst a few other strains exhibit novel genotypes/genetic constellations rarely found in other RVAs. The epidemiology and evolutionary patterns of exotic rotaviruses in humans have been thoroughly reviewed previously. On the other hand, there is no comprehensive review article devoted to exotic rotaviruses in domestic animals and birds so far. The present review focuses on the exotic/unusual rotaviruses detected in livestock (cattle and pigs), horses and companion animals (cats and dogs). Avian rotaviruses (group D, group F and group G strains), including RVAs, which are genetically divergent from mammalian RVAs, are also discussed. Although scattered and limited studies have reported rotaviruses in several exotic animals and birds, including wildlife, these data remain to be reviewed. Therefore, a section entitled "rotaviruses in exotic animals" was included in the present review.

Poster #246 EARLY PATTERNS OF SYMPTOM PROFILES USING THE POSITIVE AND NEGATIVE SYNDROME SCALE (PANSS) TO INFORM DECISIONS ON THE EXPECTED RESPONSE TO TREATMENT DURING CLINICAL TRIALS

Rotaviruses are enteric pathogens causing acute, watery, dehydrating diarrhea in various host species, including birds and mammals. This study collected data on the disease burden and strain prevalence of Group A rotavirus in animals and humans in Vellore and investigated interspecies transmission by comparison of circulating genotypes. Stool samples from children aged less than 5 years, admitted to the hospital between January 2003 and May 2006 for diarrhea and diarrheal samples from animals that were collected from a veterinary clinic and several dairy farms near Vellore between February 2007 and May 2008 were processed and subjected to RNA extraction and reverse-transcription PCR for genotyping of VP7 and VP4. Of 394 children with diarrhea, 158 (40%) were positive for rotavirus and the common G types identified were G1 (47, 29.7%), G2 (43, 27.2%), G9 (22, 13.9%), G10 (2, 1.2%), G12 (1, 0.6%) and mixed infections (27, 17.8%). The common P types were P[4] accounting for 57 (36%) samples, P[8] 57 (36%), P[11] 3 (1.8%) and P[6] 2 (1.2%). Of 627 animals, 35 (1 bullock, 2 goats, 32 cows) were found to be infected with rotavirus (5.5%). The common G types identified in order of frequency were G6 (17, 48.5%), G2 (10, 28%), G10 (4, 11%), G8 (2, 5.7%) and mixed infections (2, 5.7%). The common P types were P[6] accounting for 16 (46%) samples, P[4] 7 (20%), P[1] 3 (8.5%) and P[8] 3 (8.5%). An unusual P type P[15] was seen in one sample in combination with G10. The finding of G2 infections which are rarely identified in animals implies anthroponotic transmission since this genotype is predominantly associated with infection in humans.

Monitoring of Group A Rotaviruses in Wild-Living Birds in Hungary

Rotavirus is a common pathogen causing gastroenteritis in humans and domesticated animals. The incidence of rotavirus in wild-living animals, particularly in avian species, has not been systematically investigated. In this study 1220 fecal samples and cloacal swabs collected from wild-living birds during 2008 in Hungary were tested for the presence of group A rotaviruses by a VP6 gene-specific reverse-transcription-polymerase-chain-reaction assay. Of the 1220 samples, 276 and 944 were processed as individual and pooled specimens, respectively. Rotavirus was identified in two pooled pheasant (Phasianus colchicus) samples and two individual reed bunting samples (Emberiza schoeniclus). These data indicated a very low prevalence of group A rotaviruses (0.3%) in our sample set. Nonetheless, the present study, together with existing literature data, implies that rotavirus infections occur in a wide spectrum of feral bird species. These findings are exciting and suggest that pursuing rotavirus monitoring is needed to uncover avian rotavirus strain diversity and understand rotavirus ecology in nature.

Molecular characterization of rotaviruses in a Japanese raccoon dog ( Nyctereutes procyonoides) and a masked palm civet ( Paguma larvata) in Japan

Group A rotaviruses infect and cause diarrhea in humans and a wide range of mammals. Previous studies have suggested that some strains can cross the species barrier to infect humans ( Martella et al., 2010). However, there are few reports on infection and characterization of rotaviruses in wild animals. To estimate what types of rotaviruses infect wild animals, we investigated infection of rotaviruses in wild animals living in urban areas in Japan between 2003 and 2008. Of 145 fecal specimens obtained, we detected rotaviruses in one sample from a Japanese raccoon dog ( Nyctereutes procyonoides) (RAC-DG5) and in one sample from a masked palm civet ( Paguma larvata) (MP-CIVET66) by RT-semi-nested PCR. Sequence analyses of the VP4 and VP7 genes of RAC-DG5 and MP-CIVET66 strains revealed that these strains belong to G3bP[9] genotype. Furthermore, phylogenetic analyses showed that RAC-DG5 and MP-CIVET66 strains were closely related to human and feline rotaviruses, suggesting interspecies transmission from humans or cats. To our knowledge, this is the first report on the detection and characterization of rotaviruses in a Japanese raccoon dog and masked palm civet. These findings show that wild animals constitute a potential zoonotic risk of rotaviruses.

Rotavirus Diarrhoea in Children and Animals of Urban and Rural Nepal

Introduction Rotavirus, an etiologic agent of causing diarrhea, was identified in 25-40 percent of children with diarrhea in urban Kathmandu valley of Nepal, but the data in remote rural areas was inadequate. It was not clear whether domestic animals possessed Rotavirus and could become a source of infection in annual epidemic period. The current study described one-year prevalence of rotavirus in human beings and domestic animals in rural communities of Nepal. Objectives The purpose of this study was to reveal the association between domestic animal Rotavirus and child diarrhoea in the rural communities of Nepal. Methods Human faeces were collected from children under 5 years of age who developed diarrhoea and that from non-diarrhoeic children of equivalent ages. Animals' faecal samples were collected monthly from cows, buffaloes, pigs and dogs in the village. All samples were made 20 percent suspension in PBS and stored at -30 0 C. The study was undertaken from October 2001 to November 2002. Indirect sandwich ELISA with minor modification was applied for Rotavirus assay. Results A total of 714 stool samples from children and 772 from domestic animals were tested. Among children group, 116(16.2%) were found ELISA positive for Rotavirus whereas 8(1.03%) were positive among animal groups. The percentage of ELISA positive in hospital samples (30.6%) was significantly higher than in village (4.1%). The highest rate of rotavirus positive was also found in diarrhoeic stools (30.4%) compared to normal stools (0.87%) (P<0.05). The high incidence of diarrhea and Rotavirus was observed in winter. Rotavirus was found in 6 months to 2 years age groups more frequently than other groups while only three samples of normal feces contained Rotavirus. The incidence of Rotavirus in animals was 0.41 percent (1 of 242) of buffaloes, 2 of 254(0.78%) dogs and 3.62 percent (5 of 138) from diarrhoeal samples of pigs. Conclusion Rotavirus was found predominantly in winter and attacked 6 months to 2 years old children. The study indicated that the infected animals and hospitalized diarrhoeal children were possible source of Rotavirus infection in Nepal.

Detection and Quantification of Group C Rotaviruses in Communal Sewage

Group C rotaviruses have been recognized as a cause of acute gastroenteritis in humans, cattle, and swine, although the true epidemiologic and clinical importance of this virus in these hosts has not yet been fully established. A real-time PCR assay based on a broadly reactive primer pair was developed and used to quantitatively determine the viral load of group C rotaviruses in environmental samples. A total of 35 raw and 35 treated sewage samples collected at the same sampling time in four Hungarian sewage treatment plants during a survey in 2005 were tested for the presence of group C rotaviruses. The overall detection rates were 91% (32 of 35) for the influent and 57% (20 of 35) for the effluent samples. Molecular characterization of the amplified partial VP6 gene revealed the cocirculation of human and animal (i.e., bovine and porcine) strains that were easily distinguishable by melting curve analysis. Human strains yielded relatively high viral loads (mean, 1.2 x 10(7); median, 6.9 x 10(5) genome equivalents per liter influent sewage) and appeared to display seasonal activity over the study period, whereas animal strains appeared to circulate throughout the year at much lower average titers (bovine strains mean, 9.9 x 10(4); median, 3.0 x 10(4); porcine strains mean, 3.9 x 10(4); median, 3.1 x 10(4) genome equivalents per liter influent sewage). Our findings suggest that monitoring of communal sewage may provide a good surrogate for investigating the epidemiology and ecology of group C rotaviruses in humans and animals.

Full genome-based classification of rotaviruses reveals a common origin between human Wa-Like and porcine rotavirus strains and human DS-1-like and bovine rotavirus strains.

Group A rotavirus classification is currently based on the molecular properties of the two outer layer proteins, VP7 and VP4, and the middle layer protein, VP6. As reassortment of all the 11 rotavirus gene segments plays a key role in generating rotavirus diversity in nature, a classification system that is based on all the rotavirus gene segments is desirable for determining which genes influence rotavirus host range restriction, replication, and virulence, as well as for studying rotavirus epidemiology and evolution. Toward establishing such a classification system, gene sequences encoding VP1 to VP3, VP6, and NSP1 to NSP5 were determined for human and animal rotavirus strains belonging to different G and P genotypes in addition to those available in databases, and they were used to define phylogenetic relationships among all rotavirus genes. Based on these phylogenetic analyses, appropriate identity cutoff values were determined for each gene. For the VP4 gene, a nucleotide identity cutoff value of 80% completely correlated with the 27 established P genotypes. For the VP7 gene, a nucleotide identity cutoff value of 80% largely coincided with the established G genotypes but identified four additional distinct genotypes comprised of murine or avian rotavirus strains. Phylogenetic analyses of the VP1 to VP3, VP6, and NSP1 to NSP5 genes showed the existence of 4, 5, 6, 11, 14, 5, 7, 11, and 6 genotypes, respectively, based on nucleotide identity cutoff values of 83%, 84%, 81%, 85%, 79%, 85%, 85%, 85%, and 91%, respectively. In accordance with these data, a revised nomenclature of rotavirus strains is proposed. The novel classification system allows the identification of (i) distinct genotypes, which probably followed separate evolutionary paths; (ii) interspecies transmissions and a plethora of reassortment events; and (iii) certain gene constellations that revealed (a) a common origin between human Wa-like rotavirus strains and porcine rotavirus strains and (b) a common origin between human DS-1-like rotavirus strains and bovine rotaviruses. These close evolutionary links between human and animal rotaviruses emphasize the need for close simultaneous monitoring of rotaviruses in animals and humans.

Novel rotaviruses in animals and man.

Novel (non-group A) rotaviruses have many of the morphological, biochemical and biological properties described originally for group A rotaviruses but they do not share the same group antigens. By negative-stain electron microscopy, novel rotaviruses have the characteristic rotavirus morphology, although with some novel rotaviruses the characteristic single- and double-shelled particles may not be readily apparent. Comparison of novel rotaviruses in serological tests has revealed the existence of at least six rotavirus serogroups, A to F, with the original rotaviruses belonging to group A. As with group A rotaviruses, viruses from different animal species, including man, can belong to the same serogroup. A further point of difference between novel and group A rotaviruses is their genome profiles, which lack the triplet of segments in the 7-8-9 region of group A rotaviruses. This is a useful diagnostic aid. Novel rotaviruses have been found in farm animals and man. They can cause enteritis experimentally and infect villus enterocytes. In chickens, turkeys, lambs and pigs the viruses and/or antibody to them are commonly found, in association with either clinical or subclinical infection. In humans one type of novel virus has emerged as a cause of severe diarrhoeal disease in adults. The possible reasons for the relatively recent discovery of the novel rotaviruses are discussed.