Serotypic and genotypic characterization of human serotype 10 rotaviruses from asymptomatic neonates

Clinical, epidemiological, and genotypic characteristics of rotavirus infection in hospitalized infants and young children in Yunnan Province

Rotaviruses are the most important pathogenic cause of non-bacterial diarrhea in infants and children. Approximately 60% of hospital admissions for acute diarrhea worldwide are caused by rotavirus infection. Rotavirus infection and hospitalization among children in China are a social burden, resulting in economic loss. The prevalence and geographical distribution of rotavirus genotypes is variable, partially due to population migration. Due to the unique geographical conditions and climate in Yunnan Province, several viruses with new genotypes have emerged, and multiple genotypes have become co-epidemic. In this study, rotavirus infection screening and genetic characterization of epidemic strains were performed in 149,492 infants and children admitted to hospitals in six representative prefectures in Yunnan Province between 2019 and 2021. The prevalence of rotavirus infection was 13.39% and was highest in January and lowest in September. G9P[8] was the main epidemic rotavirus genotype. Other epidemic genotypes included G2P[4], G8P[8], G9P[4], G2P[8], G3P[8], G4P[8], G3P[4], and G4P[6]. Phylogenetic analysis revealed that locally epidemic strains were influenced by importation of strains from neighboring provinces and other Asian countries. These findings provide a scientific basis for rotavirus prevention and control and lay a foundation for preliminary studies to establish a rotavirus surveillance network in Yunnan Province.

The performance of licensed rotavirus vaccines and the development of a new generation of rotavirus vaccines: a review

Rotavirus, which causes acute gastroenteritis and severe diarrhea, has posed a great threat to children worldwide over the last 30 y. Since no specific drugs and therapies against rotavirus are available, vaccination is considered the most effective method of decreasing the morbidity and mortality related to rotavirus-associated gastroenteritis. To date, six rotavirus vaccines have been developed and licensed by local governments. Notably, Rotarix™ and RotaTeq™ have been recommended as universal agents against rotavirus infection by the World Health Organization; however, lower efficacies were found in less-developed and developing regions with medium and high child mortality than well-developed ones with low child mortality. For now, two promising novel vaccines, Rotavac™ and RotaSiil™ were pre-qualified by the World Health Organization in 2018. Other rotavirus vaccines in the pipeline including neonatal strain (RV3-BB) and several non-replicating rotavirus vaccines with a parenteral delivery strategy are currently undergoing investigation, with the potential to improve the performance of, and eliminate the safety concerns associated with, previous live oral rotavirus vaccines. This paper reviews the important developments in rotavirus vaccines in the last 20 y and discusses problems and challenges that require investigation in the future.

Molecular characterization of rotavirus group A strains circulating prior to vaccine introduction in rural coastal Kenya, 2002-2013

Background: Kenya introduced the monovalent Rotarix® rotavirus group A (RVA) vaccine nationally in mid-2014.  Long-term surveillance data is important prior to wide-scale vaccine use to assess the impact on disease and to investigate the occurrence of heterotypic strains arising through immune selection. This report presents baseline data on RVA genotype circulation patterns and intra-genotype genetic diversity over a 7-year period in the pre-vaccine era in Kilifi, Kenya, from 2002 to 2004 and from 2010 to 2013.

Methods: A total of 745 RVA strains identified in children admitted with acute gastroenteritis to a referral hospital in Coastal Kenya, were sequenced using the di-deoxy sequencing method in the VP4 and VP7 genomic segments (encoding P and G proteins, respectively). Sequencing successfully generated 569 (76%) and 572 (77%) consensus sequences for the VP4 and VP7 genes respectively. G and P genotypes were determined by use of BLAST and the online RotaC v2 RVA classification tool.

Results: The most common GP combination was G1P[8] (51%), similar to the Rotarix® strain, followed by G9P[8] (15%) , G8P[4] (14%) and G2P[4] (5%).  Unusual GP combinations—G1P[4], G2P[8], G3P[4,6], G8P[8,14], and G12P[4,6,8]—were observed at frequencies of <5%. Phylogenetic analysis showed that the infections were caused by both locally persistent strains as evidenced by divergence of local strains occurring over multiple seasons from the global ones, and newly introduced strains, which were closely related to global strains. The circulating RVA diversity showed temporal fluctuations both season by season and over the longer-term. None of the unusual strains increased in frequency over the observation period.  

Conclusions: The circulating RVA diversity showed temporal fluctuations with several unusual strains recorded, which rarely caused major outbreaks.  These data will be useful in interpreting genotype patterns observed in the region during the vaccine era.

Molecular characterization of rotavirus group A strains circulating prior to vaccine introduction in rural coastal Kenya, 2002-2013

Background: Kenya introduced the monovalent Rotarix® rotavirus group A (RVA) vaccine nationally in mid-2014.  Long-term surveillance data is important prior to wide-scale vaccine use to assess the impact on disease and to investigate the occurrence of heterotypic strains arising through immune selection. This report presents baseline data on RVA genotype circulation patterns and intra-genotype genetic diversity over a 7-year period in the pre-vaccine era in Kilifi, Kenya, from 2002 to 2004 and from 2010 to 2013. Methods: A total of 745 RVA strains identified in children admitted with acute gastroenteritis to a referral hospital in Coastal Kenya, were sequenced using the di-deoxy sequencing method in the VP4 and VP7 genomic segments (encoding P and G proteins, respectively). Sequencing successfully generated 569 (76%) and 572 (77%) consensus sequences for the VP4 and VP7 genes respectively. G and P genotypes were determined by use of BLAST and the online RotaC v2 RVA classification tool. Results: The most common GP combination was G1P[8] (51%), similar to the Rotarix® strain, followed by G9P[8] (15%) , G8P[4] (14%) and G2P[4] (5%).  Unusual GP combinations—G1P[4], G2P[8], G3P[4,6], G8P[8,14], and G12P[4,6,8]—were observed at frequencies of <5%. Phylogenetic analysis showed that the infections were caused by both locally persistent strains as evidenced by divergence of local strains occurring over multiple seasons from the global ones, and newly introduced strains, which were closely related to global strains. The circulating RVA diversity showed temporal fluctuations both season by season and over the longer-term. None of the unusual strains increased in frequency over the observation period.   Conclusions: The circulating RVA diversity showed temporal fluctuations with several unusual strains recorded, which rarely caused major outbreaks.  These data will be useful in interpreting genotype patterns observed in the region during the vaccine era.

Therapeutics and Immunoprophylaxis Against Noroviruses and Rotaviruses: The Past, Present, and Future

Background:

Noroviruses and rotaviruses are important viral etiologies of severe gastroenteritis. Noroviruses are the primary cause of nonbacterial diarrheal outbreaks in humans, whilst rotaviruses are a major cause of childhood diarrhea. Although both enteric pathogens substantially impact human health and economies, there are no approved drugs against noroviruses and rotaviruses so far. On the other hand, whilst the currently licensed rotavirus vaccines have been successfully implemented in over 100 countries, the most advanced norovirus vaccine has recently completed phase-I and II trials.

Methods:

We performed a structured search of bibliographic databases for peer-reviewed research litera-ture on advances in the fields of norovirus and rotavirus therapeutics and immunoprophylaxis.

Results:

Technological advances coupled with a proper understanding of viral morphology and replication over the past decade has facilitated pioneering research on therapeutics and immunoprophylaxis against noroviruses and rotaviruses, with promising outcomes in human clinical trials of some of the drugs and vaccines. This review focuses on the various developments in the fields of norovirus and rotavirus thera-peutics and immunoprophylaxis, such as potential antiviral drug molecules, passive immunotherapies (oral human immunoglobulins, egg yolk and bovine colostral antibodies, llama-derived nanobodies, and anti-bodies expressed in probiotics, plants, rice grains and insect larvae), immune system modulators, probiot-ics, phytochemicals and other biological substances such as bovine milk proteins, therapeutic nanoparti-cles, hydrogels and viscogens, conventional viral vaccines (live and inactivated whole virus vaccines), and genetically engineered viral vaccines (reassortant viral particles, virus-like particles (VLPs) and other sub-unit recombinant vaccines including multi-valent viral vaccines, edible plant vaccines, and encapsulated viral particles).

Conclusions:

This review provides important insights into the various approaches to therapeutics and im-munoprophylaxis against noroviruses and rotaviruses..

An enzyme-linked immuno focus assay for rapid detection and enumeration, and a newborn mouse model for human non-polio enteroviruses associated with acute diarrhea

We have recently reported significant association of non-polio enteroviruses (NPEVs) with acute and persistent diarrhea (18-21% of total diarrheal cases), and non-diarrheal Increased Frequency of Bowel Movements (IFoBM-ND) (about 29% of the NPEV infections) in children and that the NPEV-associated diarrhea was as significant as rotavirus diarrhea. However, their diarrhea-causing potential is yet to be demonstrated in an animal model system. Since the determination of virus titers by the traditional plaque assay takes 4-7 days, there is a need for development of a rapid method for virus titer determination to facilitate active clinical research on enterovirus-associated diarrhea. The goal of this study is to develop a cell-based rapid detection and enumeration method and to demonstrate the diarrhea-inducing potential of purified and characterized non-polio enteroviruses, which were isolated from diarrheic children. Here we describe generation of monoclonal and polyclonal antibodies against purified strains belonging to different serotypes, and development of an enzyme-linked immuno focus assay (ELIFA) for detection and enumeration of live NPEV particles in clinical and purified virus samples, and a newborn mouse model for NPEV diarrhea. Plaque-purified NPVEs, belonging to different serotypes, isolated from children with diarrhea, were grown in cell culture and purified by isopycnic CsCl density gradient centrifugation. By ELIFA, NPEVs could be detected and enumerated within 12h post-infection. Our results demonstrated that Coxsackievirus B1 (CVB1) and CVB5 strains, isolated from diarrheic children, induced severe diarrhea in orally-inoculated 9-12 day-old mouse pups, fulfilling Koch's postulates. The methods described here would facilitate studies on NPEV-associated gastrointestinal disease.

Rotavirus Gastroenteritis in a Neonatal Unit of a Greek Tertiary Hospital: Clinical Characteristics and Genotypes

INTRODUCTION

Rotavirus (RV) infection in neonatal age can be mild or even asymptomatic. Several studies have reported that RV is responsible for 31%-87% of pediatric nosocomial diarrhea and causes gastroenteritis outbreaks in pediatric and neonatal units.

OBJECTIVES

Study clinical characteristics, genotypes and risk factors of RV infection in neonatal age.

METHODS

A prospective study was conducted from April 2009 till April 2013 in the neonatal special care unit of the largest tertiary pediatric hospital of Greece. Fecal samples and epidemiological data were collected from each neonate with gastrointestinal symptoms. RV antigen was detected with a rapid immunochromatography test. RV positive samples were further genotyped with RT PCR and sequencing using specific VP7 and VP4 primers.

RESULTS

Positive for RV were 126/415 samples (30.4%). Mean age of onset was 18 days. Seventy four cases (58%) were hospital acquired. Seasonality of RV infection did not differ significantly throughout the year with the exception of 4 outbreaks. Genotypes found during the study period were G4P[8] (58.7%), G1P[8] (14.7%), G12P[8] (9.3%), G3P[8] (9.3%), G12P[6] (5.3%), G9P[8] (1.3%) and G2P[4] (1.3%). RV cases presented with: diarrhea (81%), vomiting (26.2%), fever (34.9%), dehydration (28.6%), feeding intolerance (39.7%), weight loss (54%), whilst 19% of cases were asymptomatic. Comparing community with hospital acquired cases differences in clinical manifestations were found.

CONCLUSIONS

Significant incidence of nosocomially transmitted RV infection in neonatal age including asymptomatic illness exists. Genotypes causing nosocomial outbreaks are not different from community strains. Circulating vaccines can be effective in prevention of nosocomial RV infection through herd immunity.

Rotavirus infections in a community based cohort in Vellore, India

INTRODUCTION

The burden of infection in communities determines the spread of rotavirus infection and disease in susceptible populations. This study reports rotavirus infection and disease in a community based birth cohort in Vellore.

METHODS

Bimonthly surveillance and diarrheal stool were collected from 452 children enrolled at birth, of whom 373 completed three years of follow up. Samples were screened for rotavirus by an ELISA and genotyped by reverse transcription polymerase chain reaction for VP7 and VP4 genes. Rotavirus incidence rates were calculated using Poisson regression equations. Risk factors associated with symptomatic and asymptomatic rotavirus infections were compared using multiple logistic regression.

RESULTS

A total of 1149 episodes of rotavirus infections occurred in 94.4% children in the cohort. Incidence of rotavirus infection was 1.04 (0.97-1.1) per child-year with 0.75 asymptomatic and 0.29 symptomatic infections per child-year. About 18% of the children were infected in the first month, mainly with the G10P[11] strain. Rotavirus infections were more prevalent during October-March, but seasonality was not as marked in rotavirus disease. Rotavirus was associated with 15.1% of mild diarrhea, 38.9% of moderate/severe diarrhea and 66.7% of very severe diarrhea. Four common G types - G1 (26.8%), G2 (16%), G10 (11.2%) and G9 (9.6%) were seen, with high rates of mixed infections and untypable samples. Male gender, presence of siblings and low maternal education were associated with rotavirus disease.

CONCLUSION

This study demonstrates that rotavirus is the most common cause of gastroenteritis in the community, and indicates that since rotavirus caused the greatest proportion of moderate and severe disease, targeted interventions such as vaccines are needed for rotavirus, in addition to health education, sanitation and appropriate treatment to decrease diarrheal disease in communities.

Review of global rotavirus strain prevalence data from six years post vaccine licensure surveillance: is there evidence of strain selection from vaccine pressure?

Comprehensive reviews of pre licensure rotavirus strain prevalence data indicated the global importance of six rotavirus genotypes, G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]. Since 2006, two vaccines, the monovalent Rotarix (RV1) and the pentavalent RotaTeq (RV5) have been available in over 100 countries worldwide. Of these, 60 countries have already introduced either RV1 or RV5 in their national immunization programs. Post licensure vaccine effectiveness is closely monitored worldwide. This review aimed at describing the global changes in rotavirus strain prevalence over time. The genotype distribution of the nearly 47,000 strains that were characterized during 2007-2012 showed similar picture to that seen in the preceding period. An intriguing finding was the transient predominance of heterotypic strains, mainly in countries using RV1. Unusual and novel antigen combinations continue to emerge, including some causing local outbreaks, even in vaccinated populations. In addition, vaccine strains have been found in both vaccinated infants and their contacts and there is evidence for genetic interaction between vaccine and wild-type strains. In conclusion, the post-vaccine introduction strain prevalence data do not show any consistent pattern indicative of selection pressure resulting from vaccine use, although the increased detection rate of heterotypic G2P[4] strains in some countries following RV1 vaccination is unusual and this issue requires further monitoring.

Perinatal stress, brain inflammation and risk of autism-review and proposal

BACKGROUND

Autism Spectrum Disorders (ASD) are neurodevelopmental disorders characterized by varying deficits in social interactions, communication, and learning, as well as stereotypic behaviors. Despite the significant increase in ASD, there are few if any clues for its pathogenesis, hampering early detection or treatment. Premature babies are also more vulnerable to infections and inflammation leading to neurodevelopmental problems and higher risk of developing ASD. Many autism "susceptibility" genes have been identified, but "environmental" factors appear to play a significant role. Increasing evidence suggests that there are different ASD endophenotypes.

DISCUSSION

We review relevant literature suggesting in utero inflammation can lead to preterm labor, while insufficient development of the gut-blood-brain barriers could permit exposure to potential neurotoxins. This risk apparently may increase in parents with "allergic" or autoimmune problems during gestation, or if they had been exposed to stressors. The presence of circulating auto-antibodies against fetal brain proteins in mothers is associated with higher risk of autism and suggests disruption of the blood-brain-barrier (BBB). A number of papers have reported increased brain expression or cerebrospinal fluid (CSF) levels of pro-inflammatory cytokines, especially TNF, which is preformed in mast cells. Recent evidence also indicates increased serum levels of the pro-inflammatory mast cell trigger neurotensin (NT), and of extracellular mitochondrial DNA (mtDNA), which is immunogenic. Gene mutations of phosphatase and tensin homolog (PTEN), the negative regulator of the mammalian target of rapamycin (mTOR), have been linked to higher risk of autism, but also to increased proliferation and function of mast cells.

SUMMARY

Premature birth and susceptibility genes may make infants more vulnerable to allergic, environmental, infectious, or stress-related triggers that could stimulate mast cell release of pro-inflammatory and neurotoxic molecules, thus contributing to brain inflammation and ASD pathogenesis, at least in an endophenotype of ASD patients.

Brief report: "allergic symptoms" in children with Autism Spectrum Disorders. More than meets the eye?

Many children with Autism Spectrum Disorders (ASD) have either family and/or personal history of "allergic symptomatology", often in the absence of positive skin or RAST tests. These symptoms may suggest mast cell activation by non-allergic triggers. Moreover, children with mastocytosis or mast cell activation syndrome (MCAS), a spectrum of rare diseases characterized by increased number of activated mast cells in many organs, appear to have ASD at a rate tenfold higher (1/10 children) than that of the general population (1/100 children). Mast cell activation by allergic, infectious, environmental and stress-related triggers, especially perinatally, would release pro-inflammatory and neurotoxic molecules. We speculate these could disrupt the gut-blood-brain barriers, thus contributing to brain inflammation and ASD pathogenesis. Increased mast cell responsiveness may define at least a subgroup of ASD subjects, who could benefit from inhibition of mast cell activation.

Mast cell activation and autism

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by varying degrees of dysfunctional communication and social interactions, repetitive and stereotypic behaviors, as well as learning and sensory deficits. Despite the impressive rise in the prevalence of autism during the last two decades, there are few if any clues for its pathogenesis, early detection or treatment. Increasing evidence indicates high brain expression of pro-inflammatory cytokines and the presence of circulating antibodies against brain proteins. A number of papers, mostly based on parental reporting on their children's health problems, suggest that ASD children may present with "allergic-like" problems in the absence of elevated serum IgE and chronic urticaria. These findings suggest non-allergic mast cell activation, probably in response to environmental and stress triggers that could contribute to inflammation. In utero inflammation can lead to preterm labor and has itself been strongly associated with adverse neurodevelopmental outcomes. Premature babies have about four times higher risk of developing ASD and are also more vulnerable to infections, while delayed development of their gut-blood-brain barriers makes exposure to potential neurotoxins likely. Perinatal mast cell activation by infectious, stress-related, environmental or allergic triggers can lead to release of pro-inflammatory and neurotoxic molecules, thus contributing to brain inflammation and ASD pathogenesis, at least in a subgroup of ASD patients. This article is part of a Special Issue entitled: Mast cells in inflammation.

Autism: an emerging 'neuroimmune disorder' in search of therapy

BACKGROUND

Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by difficulties in communication and by repetitive and stereotypic behaviors, as well as by social impairment, attention, cognitive, and learning defects. ASDs present in early childhood and their prevalence has increased significantly to 1/150 children. Despite a number of theories, the actual reasons for this increase are still not clear. There is no reliable screening test, and no definite pathogenesis or curative therapy. Consequently, there is a major gap hampering development of effective treatments.

OBJECTIVE

To review recent publications on ASDs pathogenesis and treatment with emphasis on neuroimmune processes and new therapeutic approaches.

METHODS

Mostly original papers (450) on epidemiology, possible pathogenesis or treatment of ASDs in Medline from 1990 to May 2009 were reviewed. All authors contributed to this review.

RESULTS/CONCLUSION

Increased oxidative stress and immune dysregulation are present in ASDs. Mast-cell activation may contribute to gut-blood-brain barrier disruption and brain inflammation. No effective treatments have emerged. Well-designed clinical trials with nonpsychotropic drugs were few and ASD characteristics varied considerably, making conclusions difficult. Psychotropic drugs are often used for stereotypic and aggressive behaviors. Unique combinations with antioxidant and anti-inflammatory flavonoids hold promise. New potential translational research areas and possible treatments are suggested.

Zoonotic aspects of rotaviruses

Rotaviruses are important enteric pathogens of humans and animals. Group A rotaviruses (GARVs) account for up to 1 million children deaths each year, chiefly in developing countries and human vaccines are now available in many countries. Rotavirus-associated enteritis is a major problem in livestock animals, notably in young calves and piglets. Early in the epidemiological GARV studies in humans, either sporadic cases or epidemics by atypical, animal-like GARV strains were described. Complete genome sequencing of human and animal GARV strains has revealed a striking genetic heterogeneity in the 11 double stranded RNA segments across different rotavirus strains and has provided evidence for frequent intersections between the evolution of human and animal rotaviruses, as a result of multiple, repeated events of interspecies transmission and subsequent adaptation.

Whole genome characterization of reassortant G10P[11] strain (N155) from a neonate with symptomatic rotavirus infection: identification of genes of human and animal rotavirus origin

BACKGROUND

Rotavirus G10P[11] strains have long been associated with asymptomatic neonatal infections in some parts of India. We have previously reported G10P[11] strains associated with both asymptomatic infections and severe gastrointestinal disease in neonates from Vellore in southern India, with >90% partial nucleotide and amino acid identity to the VP4, VP6, VP7 and NSP4 genes of the exclusively asymptomatic G10P[11] strain I321.

OBJECTIVES

In this study, the whole genome of a G10P[11] isolate (N155) from a neonate with severe gastrointestinal disease was characterized to determine whether there were significant differences in its genetic makeup in comparison to G10P[11] strain I321 and to establish the origin of the G10P[11] strains in Vellore.

STUDY DESIGN

PCR amplification and complete genome sequencing was carried out for all 11 gene segments of symptomatic G10P[11] rotavirus isolate N155. Nucleotide and amino acid sequence similarity with I321, other human and bovine strains for each gene segment were determined. The origin of each gene was determined based on the degree of identity to bovine or human rotavirus strains.

RESULTS

N155 was found to be a reassortant between human and bovine rotaviruses. With the exception of NSP2, gene sequences of strain N155 showed >90% identity to published sequences of I321. Gene segments encoding NSP1, 2 and 3 were of human rotavirus origin for both strains; however, phylogenetic analysis of NSP2 sequences indicated that the human parental strain that led to the origin of these bovine-human reassortant strains was different. There were no significant differences between NSP2 sequences of strains from symptomatic and asymptomatic neonates in the same setting.

CONCLUSIONS

The study shows that the difference in clinical presentations in neonates may not be due to the limited variability in the genome sequence of G10P[11] strains and that G10P[11] strains in different parts of India could have evolved through reassortment of different parental strains.

Diversity of the G3 genes of human rotaviruses in isolates from Spain from 2004 to 2006: cross-species transmission and inter-genotype recombination generates alleles

Rotavirus evolves by using multiple genetic mechanisms which are an accumulation of spontaneous point mutations and reassortment events. Other mechanisms, such as cross-species transmission and inter-genotype recombination, may be also involved. One of the most interesting genotypes in the accumulation of these events is the G3 genotype. In this work, six new Spanish G3 sequences belonging to 0-2-year-old patients from Madrid were analysed and compared with 160 others of the same genotype obtained from humans and other host species to establish the evolutionary pathways of the G3 genotype. The following results were obtained: (i) there are four different lineages of the G3 genotype which have evolved in different species; (ii) Spanish G3 rotavirus sequences are most similar to the described sequences that belong to lineage I; (iii) several G3 genotype alleles were reassigned as other G genotypes; and (iv) inter-genotype recombination events in G3 viruses involving G1 and G2 were described. These findings strongly suggest multiple inter-species transmission events between different non-human mammalian species and humans.

Rotavirus infection in the neonatal nurseries of a tertiary care hospital in India

BACKGROUND

The majority of neonatal rotavirus infections are believed to be asymptomatic, and protection from subsequent infection and disease has been reported in neonatally infected children. In this study, we present the results of a 4-year prospective surveillance in the neonatal nurseries of a tertiary care hospital in south India.

METHODS

Stool samples from neonates admitted for >48 hours either with gastrointestinal (GI) symptoms or with nonenteric pathology were screened for rotavirus. Careful assessment of clinical data was carried out. G- and P-typing for all symptomatic rotavirus positive cases and equal number of asymptomatic controls from the same month was determined by reverse transcription polymerase chain reaction.

RESULTS

Rotavirus was detected in 43.9% of 1411 neonates, including those with and without gastrointestinal disease. Rotavirus detection was significantly higher among neonates with GI disease (55.5%) than asymptomatic neonates (44.4%) (P < 0.001). Rotavirus was seen in association with diarrhea, vomiting, feed intolerance, necrotizing enterocolitis, hematochezia, gastroesophageal reflux, and abdominal distension. Diarrhea was significantly more frequent in neonates with rotavirus infection (P < 0.001) whereas uninfected neonates developed significantly more feeding intolerance (P < 0.001). Significantly greater proportion of term neonates with GI disease were positive for rotavirus than preterm neonates (P < 0.001). G10P[11] was the most common genotype associated with both symptomatic and asymptomatic infections.

CONCLUSIONS

This study documents the high rates of rotavirus infection in the neonatal nurseries and the continuing detection of the G10P[11] strain associated with GI disease in Vellore.

Rotavirus vaccines: an overview

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease. In 1999, a highly efficacious rotavirus vaccine licensed in the United States, RotaShield, was withdrawn from the market after 14 months because of its association with intussusception. Two new live, oral, attenuated rotavirus vaccines were licensed in 2006: the pentavalent bovine-human reassortant vaccine (RotaTeq) and the monovalent human rotavirus vaccine (Rotarix). Both vaccines have demonstrated very good safety and efficacy profiles in large clinical trials in western industrialized countries and in Latin America. Careful surveillance has not revealed any increased risk of intussusception in the vaccinated groups with either vaccine. The new rotavirus vaccines are now introduced for routine use in a number of industrialized and developing countries. These new safe and effective rotavirus vaccines offer the best hope of reducing the toll of acute rotavirus gastroenteritis in both developed and developing countries.

Genetic heterogeneity in the VP7 of group C rotaviruses

Evidence for a possible zoonotic role of group C rotaviruses (GCRVs) has been recently provided. To gain information on the genetic relationships between human and animal GCRVs, we sequenced the VP7 gene of 10 porcine strains detected during a large surveillance study from different outbreaks of gastroenteritis in piglets. Four GCRV strains were genetically related to the prototype GCRV porcine Cowden strain. A completely new VP7 genotype included 4 strains (344/04-7-like) that shared 92.5% to 97.0% aa identity to each other, but <83% to human GCRVs and <79% to other porcine and bovine GCRVs. A unique 4-aa insertion (SSSV or SSTI), within a variable region at the carboxy-terminus of VP7, represented a distinctive feature for these 4 unique strains. An additional strain, 134/04-18, was clearly different from all human and animal GCRVs (<85% aa identity) and likely accounts for a distinct VP7 genotype. The VP7 of a unique strain, 42/05-21, shared similar ranges of aa sequence identities with porcine and human strains (88.0-90.7% to porcine GCRVs and 85.2-88.2% to human GCRVs). Plotting the VP7 gene of strain 42/05-21 against the VP7 of human and porcine strains revealed discontinuous evolution rates throughout the VP7 molecule, suggesting different mutational pressure or a remote intragenic recombination event. These findings provide the need for future epidemiological surveys and warrant studies to investigate the pathogenic potential of these novel GCRVs in pigs.

Diversity in Indian equine rotaviruses: identification of genotype G10,P6[1] and G1 strains and a new VP7 genotype (G16) strain in specimens from diarrheic foals in India

Rotaviruses causing severe diarrhea in foals in two organized farms in northern India, during the period from 2003 to 2005, were characterized by electropherotyping, serotyping, and sequence analysis of the genes encoding the outer capsid proteins. Of 137 specimens, 47 (34.31%) were positive for rotavirus and exhibited at least five different electropherotypes (E), E1 to E5. Strains belonging to different electropherotypes exhibited either a different serotype/genotype specificity or a lack of reactivity to typing monoclonal antibodies (MAbs) used in this study. Strains belonging to E1, E2, and E5 exhibited genotype G10,P6[1], G3, and G1 specificities and accounted for 19.0, 42.9, and 9.5% of the isolates, respectively. Though they possessed G10-type VP7, the E1 strains exhibited high reactivity with the G6-specific MAb, suggesting that the uncommon combination of the outer capsid proteins altered the specificity of the conformation-dependent antigenic epitopes on VP7. E3 and E4 strains accounted for 28.6% of the isolates and were untypeable. Sequence analysis of VP7 from E4 strains (Erv92 and Erv99) revealed that they represent a new VP7 genotype, G16. The detection of unexpected bovine rotavirus-derived G10,P6[1] reassortants, G1 serotype strains, and a new genotype (G16) strain in two distant farms reveals an interesting epidemiological situation and diversity of equine rotaviruses in India.

Detection of rare G3P[19] porcine rotavirus strains in Chiang Mai, Thailand, provides evidence for origin of the VP4 genes of Mc323 and Mc345 human rotaviruses

Among 175 fecal specimens collected from diarrheic piglets during a surveillance of porcine rotavirus (PoRV) strains in Chiang Mai, Thailand, 39 (22.3%) were positive for group A rotaviruses. Of these, 33.3% (13 of 39) belonged to G3P[19], which was a rare P genotype seldom reported. Interestingly, their VP4 nucleotide sequences were most closely related to human P[19] strains (Mc323 and Mc345) isolated in 1989 from the same geographical area where these PoRV strains were isolated. These P[19] PoRV strains were also closely related to another human P[19] strain (RMC321), isolated from India in 1990. The VP4 sequence identities with human P[19] were 95.4% to 97.4%, while those to a porcine P[19] strain (4F) were only 87.6 to 89.1%. Phylogenetic analysis of the VP4 gene revealed that PoRV P[19] strains clustered with human P[19] strains in a monophyletic branch separated from strain 4F. Analysis of the VP7 gene confirmed that these strains belonged to the G3 genotype and shared 97.7% to 98.3% nucleotide identities with other G3 PoRV strains circulating in the regions. This close genetic relationship was also reflected in the phylogenetic analysis of their VP7 genes. Altogether, the findings provided peculiar evidence that supported the porcine origin of VP4 genes of Mc323 and Mc345 human rotaviruses.

Comparative study of the epidemiology of rotavirus in children from a community-based birth cohort and a hospital in South India

Rotavirus gastroenteritis is the major cause of severe dehydrating diarrhea in children worldwide. This study compares rotavirus diarrhea in 351 children in a community-based cohort and 343 children admitted to a hospital during the same period. Clinical information and fecal specimens were obtained during diarrheal episodes. Fecal samples were screened for VP6 antigen, and the positive samples were G and P typed by reverse transcription-PCR. Rotavirus was detected in 82/1,152 (7.1%) episodes of diarrhea in the community and 94/343 (27.4%) cases in the hospital. The median age of affected children (7.5 versus 10.5 months) and the mean severity of symptoms (Vesikari score, 7.6+/-3.4 versus 11+/-2.5) were lower in the community. A larger proportion of children in the community were breast-fed than were children admitted to the hospital (73% versus 34.8%). In the community, the genotypes identified in symptomatic patients, in order of frequency, were G1 (36.5%), G10 (17.1%), G2 (15.9%), and G9 (7.3%) and mixed infections (7.3%). The most common G-P combinations were G1P[8], G2P[4], G1P[4], and G10P[11]. The distribution of G types from hospitalized children was G1 (46.8%), G9 (19.1%), G2 (8.5%), G10 (1.1%), and 4.3% mixed infections. The most common G-P combinations were G1P[8] and G9P[8]. This study documents significant genetic heterogeneity of rotaviruses in the community and the hospital. G10P[11] strains resembling a vaccine candidate strain caused disease in the community, indicating the need for careful epidemiological studies as well as safety studies for the vaccine candidates.

Safety and immunogenicity of two live attenuated human rotavirus vaccine candidates, 116E and I321, in infants: results of a randomised controlled trial

We evaluated safety and immunogenicity of two orally administered human rotavirus vaccine candidates 116E and I321. Ninety healthy infants aged 8 weeks received a single dose of 116E (10(5)FFu (florescence focus units)), I321 (10(5)FFu) or placebo. There were no significant differences in the number of adverse events. Fever was reported by 6/30, 1/30 and 5/30 in the 116E, I321 and placebo groups; the corresponding figures for diarrhoea were 5/30, 8/29 and 3/30. Serum IgA seroconversion rates were 73%, 39% and 20% in the 116E, I321 and placebo groups, respectively. Vaccine virus was shed on days 3, 7 or 28 in 11/30 infants of the 116E and none in the other two groups. The 116E strain is attenuated, clinically safe and highly immunogenic with a single dose.

Full genomic analysis of human rotavirus strain B4106 and lapine rotavirus strain 30/96 provides evidence for interspecies transmission

The Belgian rotavirus strain B4106, isolated from a child with gastroenteritis, was previously found to have VP7 (G3), VP4 (P[14]), and NSP4 (A genotype) genes closely related to those of lapine rotaviruses, suggesting a possible lapine origin or natural reassortment of strain B4106. To investigate the origin of this unusual strain, the gene sequences encoding VP1, VP2, VP3, VP6, NSP1, NSP2, NSP3, and NSP5/6 were also determined. To allow comparison to a lapine strain, the 11 double-stranded RNA segments of a European G3P[14] rabbit rotavirus strain 30/96 were also determined. The complete genome similarity between strains B4106 and 30/96 was 93.4% at the nucleotide level and 96.9% at the amino acid level. All 11 genome segments of strain B4106 were closely related to those of lapine rotaviruses and clustered with the lapine strains in phylogenetic analyses. In addition, sequence analyses of the NSP5 gene of strain B4106 revealed that the altered electrophoretic mobility of NSP5, resulting in a super-short pattern, was due to a gene rearrangement (head-to-tail partial duplication, combined with two short insertions and a deletion). Altogether, these findings confirm that a rotavirus strain with an entirely lapine genome complement was able to infect and cause severe disease in a human child.

Serotype diversity and reassortment between human and animal rotavirus strains: implications for rotavirus vaccine programs

The development of rotavirus vaccines that are based on heterotypic or serotype-specific immunity has prompted many countries to establish programs to assess the disease burden associated with rotavirus infection and the distribution of rotavirus strains. Strain surveillance helps to determine whether the most prevalent local strains are likely to be covered by the serotype antigens found in current vaccines. After introduction of a vaccine, this surveillance could detect which strains might not be covered by the vaccine. Almost 2 decades ago, studies demonstrated that 4 globally common rotavirus serotypes (G1-G4) represent >90% of the rotavirus strains in circulation. Subsequently, these 4 serotypes were used in the development of reassortant vaccines predicated on serotype-specific immunity. More recently, the application of reverse-transcription polymerase chain reaction genotyping, nucleotide sequencing, and antigenic characterization methods has confirmed the importance of the 4 globally common types, but a much greater strain diversity has also been identified (we now recognize strains with at least 42 P-G combinations). These studies also identified globally (G9) or regionally (G5, G8, and P2A[6]) common serotype antigens not covered by the reassortant vaccines that have undergone efficacy trials. The enormous diversity and capacity of human rotaviruses for change suggest that rotavirus vaccines must provide good heterotypic protection to be optimally effective.

Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementation of an effective rotavirus vaccine

A safe and effective rotavirus vaccine is urgently needed, particularly in developing countries. Critical to vaccine development and implementation is a knowledge base concerning the epidemiology of rotavirus G and P serotypes/genotypes throughout the world. The temporal and geographical distribution of human rotavirus G and P types was reviewed by analysing a total of 45571 strains collected globally from 124 studies reported from 52 countries on five continents published between 1989 and 2004. Four common G types (G1, G2, G3 and G4) in conjunction with P[8] or P[4] represented over 88% of the strains analysed worldwide. In addition, serotype G9 viruses associated with P[8] or P[6] were shown to have emerged as the fourth globally important G type with the relative frequency of 4.1%. When the global G and/or P type distributions were divided into five continents/subcontinents, several characteristic features emerged. For example, the P[8]G1 represented over 70% of rotavirus infections in North America, Europe and Australia, but only about 30% of the infections in South America and Asia, and 23% in Africa. In addition, in Africa (i) the relative frequency of G8 was as high as that of the globally common G3 or G4, (ii) P[6] represented almost one-third of all P types identified and (iii) 27% of the infections were associated with rotavirus strains bearing unusual combinations such as P[6]G8 or P[4]G8. Furthermore, in South America, uncommon G5 virus appeared to increase its epidemiological importance among children with diarrhea. Such findings have (i) confirmed the importance of continued active rotavirus strain surveillance in a variety of geographical settings and (ii) provided important considerations for the development and implementation of an effective rotavirus vaccine (e.g. a geographical P-G type adjustment in the formulation of next generation multivalent vaccines).

Rotavirus genotyping: keeping up with an evolving population of human rotaviruses

The use of molecular methods for rotavirus characterisation provides not only increased sensitivity for typing, but also allows accurate and more complete characterisation of strains, and the identification of putative reassortant strains. However, due to the constant accumulation of point mutations through genetic drift, and to the emergence of novel genotypes, possibly zoonotic transmission and subsequent reassortment, the reagents and methods used require close monitoring and updating. Methods and oligonucleotide primers are described to overcome failures to type G9, G10 and P[11] rotavirus strains, and cross-reactivity identified between G10 and G3 rotaviruses.

Characterization of G10P[11] rotaviruses causing acute gastroenteritis in neonates and infants in Vellore, India

Rotavirus G10P[11] strains, which are commonly found in cattle, have frequently been associated with asymptomatic neonatal infections in India. We report the finding of G10P[11] strains associated with severe disease in neonates in Vellore, southern India. Rotavirus strains from 43 fecal samples collected from neonates with or without gastrointestinal symptoms between 1999 and 2000 were genotyped by reverse transcription-PCR. Forty-one neonates (95%) were infected with G10P[11] rotavirus strains, and 63% of the infections were in children who had gastrointestinal symptoms, including acute watery diarrhea. G10P[11] strains were also seen infecting older children with dehydrating gastroenteritis in Vellore. Characterization of the genes encoding VP7, VP4, VP6, and NSP4 of these strains revealed high sequence homology with the corresponding genes of the asymptomatic neonatal strain I321, which in turn is very closely related to bovine G10P[11] strains circulating in India. No significant differences were seen in the sequences obtained from strains infecting symptomatic neonates or children and asymptomatic neonates.

Quantitation of group A rotavirus by real-time reverse-transcription-polymerase chain reaction: correlation with clinical severity in children in South India

The epidemiology and pathogenesis of rotaviruses are not completely understood, although recent developments in polymerase chain reaction (PCR) techniques now make it possible to quantify the viral load during an infective episode and investigate its relevance to clinical features of the disease. We studied rotavirus-positive stool samples collected from 10 children without symptoms of gastroenteritis and from 81 children with acute gastroenteritis and in whom the clinical severity of disease was recorded. A semi-quantitative real-time reverse-transcription (RT)-PCR was used to estimate the rotavirus load and to assess its correlation with the Vesikari score for severity of diarrhoea. There was a significant negative correlation (r = -0.80, P < 0.001) between severity and the PCR cycle at which the PCR amplicons were detectable (crossing point) on the assay, indicating that children with more severe diarrhoea excrete more virus than children with less severe disease.

Construction and characterization of rhesus monkey rotavirus (MMU18006)- or bovine rotavirus (UK)-based serotype G5, G8, G9 or G10 single VP7 gene substitution reassortant candidate vaccines

Group A rotaviruses are the single most important etiologic agents of severe diarrhea of infants and young children worldwide and have been estimated to be responsible for approximately 650,000-800,000 deaths annually in children <5-year-old in the developing countries. Thus, the development of a safe and effective rotavirus vaccine has been a global public health goal. Epidemiologic surveillance of rotavirus VP7 (G) serotypes-genotypes conducted in various populations throughout the world has repeatedly shown that approximately 90% of the typeable rotavirus isolates belong to G1-G4. For these reasons, we have developed a rhesus rotavirus (RRV)-based or bovine rotavirus (UK)-based quadrivalent vaccine which is designed to provide antigenic coverage for G1-G4. More recently, G serotypes-genotypes other than G1-G4, including G5, G8-G10, have been detected in various parts of the world. Although the occurrence of such uncommon G types, except for G9, has been focal, still, in order to "be ready and prepared", we have constructed and characterized eight additional reassortant rotavirus vaccines, each of which bears a single human or bovine VP7 gene encoding G serotype 5, 8, 9 or 10 specificity and the remaining 10 genes of RRV strain MMU18006 or bovine rotavirus strain UK. These candidate vaccines could be evaluated singly in special populations or in combination with a RRV- or an UK-based quadrivalent vaccine to broaden its G serotype specificity.

Distribution of rotavirus VP7 genotypes among children suffering from watery diarrhea in Kolkata, India

A combined reverse transcriptase-polymerase chain reaction (RT/PCR) was used to produce cDNA of the VP7 gene of rotavirus present in the stool samples. A total of 150 rotavirus positive stool samples were used in this study. Multiplex PCR, using the type specific primers, revealed the presence of G1 (49/150, 32.7%), G2 (27/150, 18%) and G4 (30/150, 20%) genotypes among the samples collected during 1999-2000 from children suffering from acute watery diarrhea. Eighteen samples (12%) were of mixed genotype and the remaining 16 samples (10.6%) could not be typed. Comparative analysis of the full length genes of the representative strains with corresponding genotypes incorporated in the human-rhesus rotavirus tetravalent vaccine (RRV-TV) formulation demonstrates variations of the circulating G1, G2 and G4 strains with the corresponding G genotypes present in the vaccine strain.

Neonatal rotavirus infection in Belém, northern Brazil: nosocomial transmission of a P[6] G2 strain

A total of 614 fecal specimens were obtained during a survey for rotavirus infection conducted between May 1996 and May 1998 among 437 newborns admitted to special care nurseries at a public hospital in the urban area of Belém, Brazil. Routine stool samples were taken weekly from all babies up to the age of 28 days. Overall, 51 (11.7%) of the neonates excreted rotaviruses while in hospital, of whom 42 (82.3%) developed asymptomatic nosocomial infection; nosocomial infection was also proved in five of the nine patients with diarrhea. Three distinct RNA profiles were detected, of which one short electropherotyping pattern was far more frequent ( approximately 90% of the strains). Using monoclonal antibody-based enzyme immunoassays, 32 (62.7%) of the rotavirus-positive strains were classified as G2, and 1 (1.9%) as mixed G1 and G2. A G serotype could not be assigned to 18 (35.3%) of the isolates. A reverse transcription-polymerase chain reaction was used for determining the VP4 type-specificity of a subset of 28 rotavirus-positive samples. Characterization of the VP7-genotype specificity was also sought for 18 of these latter strains. Overall, P[6] and G2 genotypes were identified in 93% and 94% of tested samples respectively, with results being further confirmed by Southern hybridization. Although surveillance was conducted during a 25-month period, 50 (98%) of 51 rotavirus isolates clustered between January and December 1997. The earliest [P6]G2 rotavirus infections were detected by late January 1997, involving two (13- and 14-day-old) babies admitted with acute diarrhea. Thereafter, strains bearing these genotype specificities were identified among five infants with hospital-acquired gastroenteritis, followed by 16 others who were infected asymptomatically. This is the first report from Brazil describing nosocomial transmission of P[6]G2 rotavirus strains among neonates.

Characterization of nontypeable rotavirus strains from the United States: identification of a new rotavirus reassortant (P2A[6],G12) and rare P3[9] strains related to bovine rotaviruses

Among 1316 rotavirus specimens collected during strain surveillance in the United States from 1996 to 1999, most strains (95%) belonged to the common types (G1 to G4 and G9), while 5% were mixed infections of common serotypes, rare strains, or not completely typeable. In this report, 2 rare (P[9],G3) and 2 partially typeable (P[6],G?; P[9],G?) strains from that study were further characterized. The P[6] strain was virtually indistinguishable by hybridization analysis in 10 of its 11 gene segments with recently isolated P2A[6],G9 strains (e.g., U.S.1205) from the United States, but had a distinct VP7 gene homologous (94.7% a.a. and 90.2% nt) to the cognate gene from P1B[4],G12 reference strain L26. Thus, this serotype P2A[6],G12 strain represents a previously unrecognized reassortant. Three P3[9] strains were homologous (97.8-98.2% aa) in the VP8 region of VP4 to the P3[9],G3 feline-like reference strain AU-1, but had a high level of genome homology to Italian bovine-like, P3[9],G3 and P3[9],G6 rotavirus strains. Two of the U.S. P3[9] strains were confirmed to be type G3 (97.2-98.2% VP7 aa homology with reference G3 strain AU-1), while the other was most similar to Italian bovine-like strain PA151 (P3[9],G6), sharing 99.0% a.a. homology in VP7. Cross-neutralization studies confirmed all serotype assignments and represented the first detection of these rotavirus serotypes in the United States. The NSP4 genes of all U.S. P3[9] strains and rotavirus PA151 were most closely related to the bovine and equine branch within the DS-1 lineage, consistent with an animal origin. These results demonstrate that rare strains with P and G serotypes distinct from those of experimental rotavirus vaccines circulate in the United States, making it important to understand whether current vaccine candidates protect against these strains.

Glycosphingolipid binding specificities of rotavirus: identification of a sialic acid-binding epitope

The glycosphingolipid binding specificities of neuraminidase-sensitive (simian SA11 and bovine NCDV) and neuraminidase-insensitive (bovine UK) rotavirus strains were investigated using the thin-layer chromatogram binding assay. Both triple-layered and double-layered viral particles of SA11, NCDV, and UK bound to nonacid glycosphingolipids, including gangliotetraosylceramide (GA1; also called asialo-GM1) and gangliotriaosylceramide (GA2; also called asialo-GM2). Binding to gangliosides was observed with triple-layered particles but not with double-layered particles. The neuraminidase-sensitive and neuraminidase-insensitive rotavirus strains showed distinct ganglioside binding specificities. All three strains bound to sialylneolactotetraosylceramide and GM2 and GD1a gangliosides. However, NeuAc-GM3 and the GM1 ganglioside were recognized by rotavirus strain UK but not by strains SA11 and NCDV. Conversely, NeuGc-GM3 was bound by rotaviruses SA11 and NCDV but not by rotavirus UK. Thus, neuraminidase-sensitive strains bind to external sialic acid residues in gangliosides, while neuraminidase-insensitive strains recognize gangliosides with internal sialic acids, which are resistant to neuraminidase treatment. By testing a panel of gangliosides with triple-layered particles of SA11 and NCDV, the terminal sequence sialyl-galactose (NeuGc/NeuAcalpha3-Galbeta) was identified as the minimal structural element required for the binding of these strains. The binding of triple-layered particles of SA11 and NCDV to NeuGc-GM3, but not to NeuAc-GM3, suggested that the sequence NeuGcalpha3Galbeta is preferred to NeuAcalpha3Galbeta. Further dissection of this binding epitope showed that the carboxyl group and glycerol side chain of sialic acid played an important role in the binding of such triple-layered particles.

Sequence analysis of VP4 and VP7 genes of nontypeable strains identifies a new pair of outer capsid proteins representing novel P and G genotypes in bovine rotaviruses

During a limited epidemiological study, the serotype specificities of several isolates of bovine rotavirus, exhibiting identical electropherotypes, from a single cattle farm near Bangalore, India, could not be determined using a panel of serotyping monoclonal antibodies (MAbs) specific for G serotypes 1-6 and 10. To determine the genotypes of these isolates, the nucleotide sequences of the genes encoding the outer capsid proteins VP4 and VP7 of two representative isolates, Hg18 and Hg23, were determined. The corresponding gene sequences from the two isolates were identical, indicating that these isolates represented a single strain of bovine rotavirus. Comparison of the VP4 nucleotide (nt) and the deduced amino acid (aa) sequences with those of several human and animal rotavirus strains representing all of the currently recognized 20 different VP4 (P) genotypes revealed low nt and aa sequence identities of 61.0 to 74.2% and 57.9 to 78.2% for VP4. The percentages of amino acid homology for the VP8* and VP5* regions of VP4 were 37.7 to 67.9 and 68.1 to 84.2%, respectively. The nt and aa sequences of the VP7 gene were also distinct from those of human and animal strains belonging to the previously established 14 VP7(G) serotypes (65.9 to 75.5% nt and 59.5 to 77.6% aa identities). These findings suggest the classification of the VP4 and VP7 genes of the bovine isolates represented by Hg18 as new P and G genotypes and provide further evidence for the vast genetic/antigenic diversity of group A rotaviruses.

Comparative studies of human rotavirus serotype G8 strains recovered in South Africa and the United Kingdom

Epidemiological studies on the VP7 serotype prevalence of human rotaviruses in South Africa and the United Kingdom identified several strains which could not be serotyped as G1-G4 by monoclonal antibodies. Further analysis of these strains with a G8-specific monoclonal antibody and with probes for human rotaviruses confirmed them as G8 rotaviruses. These G8 strains exhibited a high degree of sequence identity when compared with each other and with other rotavirus G8 strains. Five South African strains were further characterized as VP6 subgroup I, but with a long RNA electropherotype, which is similar to the G8 strains previously isolated in Finland. In the UK strains, one was VP6 subgroup II with a long RNA electropherotype (similar to the Italian G8 strain). The other two were subgroup I with a short RNA electropherotype. None of these strains exhibited the super-short RNA electropherotype described in the prototype G8 strains recovered from Indonesia (69M).

Relative frequencies of G and P types among rotaviruses from Indian diarrheic cow and buffalo calves

While an increasing number of studies suggest that there is a high prevalence of rotaviruses with P8[11], a typical P type of bovine rotavirus (BRV), among human neonates or infants in India, no data are available on the distribution of G and P types of Indian BRVs. Thus, fecal specimens were collected from cow and buffalo calves under 1 month of age on organized dairy farms in India during the period between 1994 and 1997, and 36 rotavirus-positive specimens were used to determine the relative frequencies of the G and P types of Indian BRVs. As to the G type, G10 was predominant (83%), followed by G6 (6%). The majority (94%) of BRVs had P8[11], and only one isolate possessed P6[1]. The most common combination of G and P types was G10P8[11] (81%), followed by G6P6[1] (3%) and G6P8[11] (3%). The high prevalence of BRVs possessing P8[11] VP4s strongly supports the hypothesis that BRVs may cross the host species barrier and circulate among neonates in India.

Detection of rotavirus types G8 and G10 among Brazilian children with diarrhea

Characterization of 49 rotavirus-positive stool specimens from children with diarrhea in the state of Rio de Janeiro, Brazil, in 1996 and 1997 revealed a great diversity of rotavirus G types. Conventional types G1 and G3 accounted for 27 and 12% of the infections, respectively, whereas 60% of the infections were caused by unconventional types G5 (25%), G10 (16%), and G8 (4%) and mixed G types (16%).

Distribution of G serotypes and P genotypes of bovine group A rotavirus isolated in Japan

OBJECTIVE

To identify the distribution of G serotype and P genotype of bovine group A rotavirus in Japan.

DESIGN

Detection, isolation, electropherotyping, G serotyping and P genotyping of bovine group A rotavirus in 167 diarrhoeal faecal samples.

PROCEDURE

Bovine group A rotavirus was detected and isolated, and bovine group A rotavirus isolates were identified electropherotype by polyacrylamide gel electrophoresis and G serotype and P genotype by reverse transcription-poly-merase chain reaction.

RESULTS

Twenty-eight bovine group A rotavirus strains were isolated from 167 samples. Electropherotypes of the bovine group A rotavirus isolates were identified as long-genome electropherotype and the most prevalent combination of G serotype and P genotype of the bovine group A rotavirus isolates was G6P5 (25/28; 89.3%), followed by G6P11 (2/28; 7.1%) and G10P11 (1/28; 3.6%).

CONCLUSION

These results suggest that the bovine group A rotavirus exhibiting G6P5 is the most common in Japan.