Atypical Rotaviruses Research Articles

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.

Emergence and spread of G3P[8] rotaviruses possessing an equine-like VP7 and a DS-1-like genetic backbone in the Basque Country (North of Spain), 2015

In March 2015, an atypical G3P[8] rotavirus with an equine-like VP7 gene was detected in Gipuzkoa (Basque Country, Spain) and spread contributing significantly to the seasonal epidemic. The strain was identified in fecal samples collected from 68 patients, mainly children from rural and urban settings with acute gastroenteritis, representing 14.9% of the 455 rotavirus strains genotyped between July 2014 and June 2015. Seven patients (10.3%) were hospitalized. Full genome analysis of six of these strains revealed a DS-1-like genotype constellation, G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2, and showed that most genome segments shared the highest nucleotide sequence identity with strains isolated in Japan, Thailand, Australia and the Philippines. The strains of Gipuzkoa were similar to novel G3P[8] reassortant rotaviruses with an equine-like VP7 gene and a DS-1-like genetic backbone that emerged in the Asia-Pacific Region in 2013. The study highlights the circulation of these atypical rotaviruses outside the Asia-Pacific Region of origin, and their emergence in a European Region. Due to their unusual genotype constellation, these strains pose a challenge for the rotavirus strain surveillance, since G-/P-typing, the most commonly used classification system, cannot identify this type of intergenogroup reassortants.

Electrophoretic patterns of human rotavirus strains prevailing among hospitalized children with acute gastroenteritis

Polyacrylamide gel electrophoresis (PAGE) and silver staining was applied to detect rotavirus dsRNA from acute diarrheic stool of 365 hospitalized children below 5 years of age. The study was conducted at Mymensingh and Sunamgonj districts, Bangladesh from January 2002 to February 2003. Among 345 stool specimens tested, 86 (24.9%) were positive by PAGE. The rate of infection was highest in 0-12 months of age and declined significantly with increasing age. Males were slightly more infected than females and infection rate was more in winter. Twelve different electropherotypes were identified, of them eight were long and four were short. RNA profiles of the analyzed specimens, 88.6% were long and 11.4% were short patterns. Two of these long patterns (2F N 1 L, 2F N 3(U) L) circulated through out the study period and a single type was predominant (2F N 1 L). Mixed electropherotypes were also detected. Electropherotyping technique can be applied routinely to study the prevalence and epidemiological features of rotavirus infection. It is an excellent method for studying genomic variation, tracing mixed infections, detecting atypical rotaviruses lacking group-antigen and characterizing virus strains in outbreaks.

Genetic analysis of Group A rotaviruses: evidence for interspecies transmission of rotavirus genes.

Rotaviruses are the major cause of severe gastroenteritis in young children and animals. The rotavirus genome is composed of eleven segments of double-stranded RNA and can undergo genetic reassortment during mixed infections, leading to progeny viruses with novel or atypical phenotypes. There are numerous descriptions of rotavirus strains isolated from human and animals that share genetic and antigenic features of viruses from heterologous species. In many cases, genetic analysis by hybridization has clearly demonstrated the genetic relatedness of gene segments to those from viruses isolated from different species. Together with the observation that some virus strains appear to have been transmitted to a different species as a whole genome constellation, these data suggest that interspecies transmission occurs naturally, albeit at low frequencies. Although interspecies transmission has not been documented directly, there is an increasing number of reports of atypical rotaviruses that are apparently derived from transmission between: humans, cats and dogs; humans and cattle; humans and pigs; pigs and cattle; and pigs and horses. Interspecies evolutionary relationships are supported by phylogenetic analysis of rotavirus genes from different species. The emergence of novel strains derived from interspecies transmission has implications for the design and implementation of successful human rotavirus vaccine strategies.

Prevalence of enteric viruses in human immunodeficiency virus seropositive patients in Venezuela.

The prevalence of enteric viruses associated with gastroenteritis was determined in 125 stool samples from patients infected with the human immunodeficiency virus (HIV), with or without diarrhea. Diagnostic assays included enzyme immunoassays for the identification of rotavirus, adenovirus, and Norwalk virus; polyacrylamide gel electrophoresis for atypical rotaviruses and picobirnaviruses and polymerase chain reaction for astrovirus. Enteric viruses were detected in 6.4% (8 of 125) of the stools collected: five (4.0%) samples positive for adenoviruses, and three (2.3%) samples positive for picobirnaviruses were detected. No rotavirus, astrovirus, or Norwalk virus were observed. Only one of the viruses identified (adenovirus) was found in a sample from a patient with diarrhea. Viruses were detected in 10% of the patients with AIDS, 14% of the symptomatic patients, and none of the asymptomatic persons. These results do not support a major role for enteric viruses in the diarrhea suffered by HIV-infected patients.

An outbreak of diarrhoea associated with atypical rotaviruses in goat kids

The presence of rotaviruses was investigated in the faeces of 31 goat kids in a dairy herd that experienced an outbreak of severe diarrhoea which caused dehydration, anorexia and prostration in seven (22·6 per cent) of them. All the affected animals were two to three days old. A group A-specific elisa failed to detect rotaviruses in any of the samples but the characteristic electropherotype of group B rotaviruses was observed by electrophoresis in polyacrylamide gels in six of the animals. A highly significant statistical association between the shedding of rotavirus and the occurrence of diarrhoea was demonstrated. All the rotaviruses were detected in animals three to four days old. Cryptosporidium parvum, Clostridium perfringens and enterotoxigenic Escherichia coli were not detected in the seven diarrhoeic animals.

Viral etiology in travellers' diarrhea

Virological examinations were performed on stools obtained from 1,264 overseas travellers with diarrhea at Nagoya International Airport between 1986 and 1991. Group A rotavirus was detected in 11 samples (0.87%) by latex agglutination method, but other viral agents such as atypical rotaviruses and small round structured viruses were not observed by electron microscopic analysis. Rotaviruses were detected in various age groups, but the positive rate of rotavirus in females (6/398) was higher than that in males (5/866). Seasonal variation in the detection of rotavirus was observed. Entero 71 was isolated from one of 11 rotavirus-positive cases, but the other 10 cases were not associated with enteroviruses. All rotavirus-positive cases were negative for isolation of enteropathogenic bacteria.

The correct sequence of the porcine group C/Cowden rotavirus major inner capsid protein shows close homology with human isolates from Brazil and the U.K.

Amino acid sequence alignments between the human group C/Bristol and the published porcine group C/Cowden VP6 proteins have revealed a region of extreme sequence divergence. We have been unable to confirm the nucleotide sequence of the Cowden VP6 gene corresponding to this region of divergence. Direct sequencing of a PCR-amplified cDNA pool has revealed a frame shift, and three nucleotide changes, within the published sequence of the porcine (Cowden) VP6 gene. The corrected sequence of the porcine protein revealed a closer homology with VP6 from the Bristol strain and two new human group C rotavirus isolates. Atypical rotaviruses have been detected in the feces of children living in Belém, Brazil, and Preston, U.K. Direct sequencing of PCR-amplified cDNA corresponding to the VP6 gene of one isolate from each location confirmed the presence of a group C rotavirus. The complete nucleotide sequences of the VP6 genes from the group C/Belém and C/Preston rotaviruses contained an open reading frame of 1185 nucleotides (395 amino acids; deduced Mr 44,669 Dal. The Belém, VP6 gene demonstrated 97.9% nucleotide homology with the human group C/Bristol VP6 gene and 83.4% nucleotide homology (91.6% deduced amino acid homology) with the corrected porcine group C/Cowden sequence. The Preston VP6 gene demonstrated 99.6% nucleotide homology with the human group C/Bristol VP6 gene and 84.0% nucleotide homology (91.6% deduced amino acid homology) with the corrected porcine group C/Cowden sequence. Remarkably, the deduced amino acid sequence of the Brazilian strain was identical to that of the U.K. isolates.

Molecular epidemiology of rotaviruses associated with pediatric diarrhea in Bangkok, Thailand.

Rotavirus diarrhea in 453 pediatric patients (29.8% of 1,518) was studied in greater Bangkok during 1985 to 1987. The disease persisted all year, increasing in incidence from August to January (30 to 50%). Polyacrylamide gel electrophoresis of rotavirus RNA from these patients and from an additional 46 patients of a 1982 to 1983 epidemic revealed 26 electropherotypes, 4 with short (S) and 22 with long (L) RNA profiles. Of the analyzed specimens, 85.5% were L forms. Only one or a few electropherotypes predominated in each epidemic, whereas others appeared sporadically at low frequencies. Shifts in the predominant electropherotypes were observed in every epidemic. Of these, 126 strains were tested for subgroup and serotype by monoclonal antibody enzyme immunoassay. Serotype 4 prevailed from 1982 to 1983, while serotype 1 was encountered more frequently than serotypes 2 and 4 from 1985 to 1987. A complete correlation was found between the electrophoretic migration of segments 10 and 11 and the serologically defined subgroup specificity. Distinct electropherotypes occurred within the same serotype, and strains with the identical electropherotype always showed the same serotype specificity. No specific electropherotype or serotype correlated with patient age. In this study, atypical rotaviruses and mixed infections with different rotaviruses were identified.

Comparison of Polyacrylamide Gel Electrophoresis, an Enzyme-Linked-Immunosorbent Assay, and an Agglutination Test for the Direct Identification of Bovine Rotavirus from Feces and Coelectrophoresis of Viral RNA's

The dsRNA concentrated polyacrylamide gel electrophoresis (CPAGE) detected rotavirus directly from 19% of 77 stool specimens from diarrheic calves. A commercial enzyme-linked immunosorbent assay (ELISA) detected 25%, latex agglutination test, 23%, and polyacrylamide gel electrophoresis (PAGE), 19%. Establishing CPAGE as the "standard," the commercial ELISA and the latex agglutination test both had higher sensitivity (84%) than PAGE (79%). However, PAGE produced the highest specificity (100%), followed by agglutination (88%) and ELISA (84%). The commercial ELISA had a slightly higher sensitivity than agglutination, PAGE, and CPAGE, but the ELISA specificity was generally lower. The latex agglutination test had a lower sensitivity than ELISA, but specificity was higher. Agglutination had similar negative predictive values (94%), compared with agglutination and PAGe, but had the lowest positive predictive value (a measure of accuracy) (70%). Agreement with CPAGE was highest for PAGE (94.8%), followed by agglutination (87%) and ELISA (84.4%). The calculated percentages of total disagreement with all other tests indicated that ELISA differed from the other rotavirus detection assays in 10.4% of the cases, agglutination in 7.8%, PAGE in 2.6%, and CPAGE in 1.3%. The 2 PAGE assays allowed the detection of atypical rotaviruses from feces based on the characteristic "super-short" migration pattern of the 11 genomic segments of rotaviruses and of other members of the Reoviridae.

Group C rotavirus associated with fatal enteritis in a family outbreak

A family outbreak of gastroenteritis involving three adults and three children is described in which diarrhoea and vomiting were the main clinical features. One infant died in whom no pathogens could be detected in either small or large intestinal postmortem samples. Stool samples from two symptomatic siblings contained rotaviruses as demonstrated by electron microscopy. Both of these faecal samples were negative when assayed in a group A specific rotavirus enzyme-linked immunosorbent assay (ELISA) and subsequent genomic analysis of these rotaviruses was suggestive of group C rotavirus. Serological evidence showed that these atypical rotaviruses were members of serogroup C. Other atypical rotaviruses in faecal samples from sporadic cases in symptomatic children were detected over a similar time period and location. These had electrophoretic RNA profiles similar to those in the family outbreak. Furthermore, seroepidemiological studies detected group C rotavirus antibody in blood donors resident in the location of the family outbreak.

C群ロタウイルスの疫学的研究

By electron microscopy survey of acute gastroenteritis of children in Matsuyama, rotaviruses were detected in 561 of 2479 fecal samples obtained between October, 1984 and September, 1988, in which 60 atypical and 259 typical rotaviruses, so far tested, were detected by polyacrylamide gel electrophoresis (PAGE) of viral RNA. Out of 60 atypical rotaviruses, 5 were observed in 1985, 7 in 1986, none in 1987 and 48 in 1988. These atypical rotaviruses were morphologically indistinguishable from typical ones and showed very similar RNA migration patterns of PAGE to those of group C rotavirus. Furthermore, one atypical virus (86-542) reacted with antiserum against a porcine group C rotavirus in immune electron microscopy, while it did not react with anti-group A rotavirus serum. On the other hand, hyperimmune guinea pig antiserum against 86-542 reacted with a couple of atypical rotavirus including viruses isolated in 1988, so far tested, but did not react with any of the typical viruses. These findings showed that atypical rotaviruses which were endemic in Matsuyama city in 1988 were defined as group C rotavirus. Moreover, these group C rotaviruses showed two kind of RNA migration patterns in PAGE, which clearly discriminated the virus were isolated before and after 1987. Epidemiological features of group C rotavirus were as follows. Children from whom group C rotavirus was isolated were older than those from of whom group A rotavirus was isolated. The epidemic season was in February through April, compared to December through March in group A virus. Retrospective seroepidemiological study by immune adherence hemagglutination test (IAHA) using the purified 86-542 virus as antigen indicated that 15 of 78 sera of children obtained in 1971 already possessed IAHA antibody against group C rotavirus.

Atypical rotavirus among diarrhoeic children living in Belém, Brazil

Atypical rotaviruses were detected in faeces from two diarrhoeic children living in Belém, Pará, Brazil. Rotavirus particles were detected by electron microscopy and the RNA electrophoresis showed patterns which were compatible with group C rotaviruses. Tests for the presence of group A antigen by enzyme-linked-immunosorbent assay (ELISA) were negative. The two children had three successive rotavirus infections and in both cases the atypical strains were excreted at the time of the third infection, causing a mild and short-lasting disease.

Rotavirus epidemiology in Vellore, south India: group, subgroup, serotype, and electrophoretype

Rotaviruses were detected in 163 of 916 (17.8%) specimens collected from children under 3 years of age with gastroenteritis in Vellore, South India, between August 1983 and July 1985. Rotaviruses were detected throughout the study period, with a peak prevalence in December to February (winter) and June to August (southwest monsoon season). A total of 117 rotavirus strains were tested for subgroup, serotype, and rotavirus double-stranded RNA electrophoretic migration pattern; 24.8% of the strains were subgroup I, 69.2% were subgroup II, and 6.0% were neither subgroup I nor subgroup II. Subgroup I and II strains were circulating concurrently throughout the study. Of the 117 rotavirus strains, 32 (27.4%) were serotyped; 15 were serotype 1, 3 were serotype 2, 2 were serotype 3, and 12 were serotype 4. Three serotypes were circulating concurrently during the periods of peak rotavirus prevalence. In 100 of the 117 strains (85.4%) an RNA pattern was detected. One unusual subgroup I group A rotavirus with a long migration pattern and four atypical rotaviruses serologically related to group C were also detected.

Lack of Genomic Reassortment Following Infection of Infant Rats with Group A and Group B Rotaviruses

Rotaviruses are members of the Reoviridae family of viruses and are recognized as an important cause of diarrheal disease in infants and young children [1]. Rotaviruses have been shown to display variation in neutralization specificities on the basis of epitopes mapped to outer capsid proteins [2]. Until recently it was thought that all rotaviruses shared common group-reactive antigenic determinants located on internal proteins. It is the widespread distribution of these determinants that has allowed for the diagnosis and study of rotavirus gastroenteritis by means of sensitive immunoassay systems [3]. Recently, however, a number of fastidious rotavirus strains have been identified that do not contain these common determinants. These agents have been called atypical rotaviruses or non-group A rotaviruses to distinguish them from the group A viruses that contain the recognized common antigen. The non-group A rotaviruses have been further divided into groups B, C, D, and E on the basis of the length and nucleotide content of RNA gene segments [4], nucleic acid hybridization [5], and antigenic reactivity [6]. Non-group A rotaviruses have been identified as etiologic

Atypical rotaviruses in Australian pigs.

Atypical rotaviruses of two different electropherotypes were identified by PAGE in 16 out of 237 (5.3%) diarrhoeic faecal samples from piglets. A cDNA probe derived from a group B rotavirus hybridized strongly to two samples (of 3 tested) with electropherotypes suggestive of groups B or E, identifying them as group B. The electropherotype(s) of seven samples were typical of group C. By immunofluorescence, antibodies to group B, C, and E rotaviruses have been detected in sera from Australian sows, so it appears that atypical rotaviruses belonging to three different groups occur in pigs in this country.

Atypical rotavirus in chickens in Argentina

In Argentina the presence of rotavirus was investigated in a chicken flock experiencing periodic episodes of diarrhoea during the winter of 1986. All the samples analysed were negative by the enzyme-linked immunosorbent assay (ELISA). However, when samples were observed by electron microscopy, particles which were indistinguishable from standard rotaviruses were detected in some samples. Ten of the 36 samples were positive after polyacrylamide gel electrophoresis (PAGE) analysis, all of them showing the same electropherotype. Based on these results these viruses were classified as rotavirus-like or atypical rotaviruses.

Atypical human rotaviruses in Hungary

Summary Of 105 human rotaviruses, two atypical, antigenically distinct rotaviruses (pararotaviruses) were isolated in Hungary. A 4-year old boy and a 3½-year old girl, both with gastroenteritis, vomiting and moderate fever, shed these viruses. Electrophoretic patterns of viral RNA extracted from the two faecal specimens appeared to be related to patterns of group C rotaviruses.

Characterization of rotaviruses isolated from pigs with diarrhoea in Venezuela

The prevalence of porcine rotavirus infection was studied in 15 different herds located in the north-western region of Venezuela. The presence of rotavirus was studied by direct electron microscopy (EM) and by an enzyme-linked immunosorbent assay (ELISA). From 136 samples analyzed during the six months of the study (September 1983–February 1984), 38 (27.9%) were found to be positive for rotaviruses, with infection more common in animals that were 4–6 weeks old. Atypical rotaviruses were not detected in any of the samples examined. Most rotavirus positive specimens were subgrouped using specific monoclonal antibodies in an ELISA test. The majority of the samples (26 out of 38) were found to exhibit Subgroup I antigenicity. Only two specimens, collected from the same herd in two consecutive months, were found to belong to Subgroup II. To characterize further the circulating rotaviruses, electrophoretic analysis of the RNA genome was performed on samples selected from nine different herds. Great variability in the RNA electropherotypes was observed. No correlation was found between subgroup specificity and the migration of the two smaller segments (Genes 10 and 11), as has been described for human rotaviruses.

A Survey of Enteric Viruses of Turkey Poults

Intestinal samples from 91 turkey flocks between 1 day and 5 weeks of age were examined for enteric viruses using electron microscopy and electropherotyping. These flocks originated from eight operations in six states. Individual flocks were sampled only once. At the time of sampling, 31 flocks were considered normal/healthy and 60 were considered to have enteric disease. The most frequently identified viruses from diseased flocks were astroviruses (78%) and rotavirus-like viruses (RVLVs) (67%). Far less frequent were rotaviruses (22%), atypical rotaviruses (12%), enteroviruses (5%), and reoviruses (2%). Only 10% of the samples from diseased flocks were negative, but 48% of the samples from normal/healthy flocks were negative. Astroviruses and RVLVs were far less frequent in normal/healthy flocks than in diseased flocks, but rotaviruses were identified slightly more often. No viruses were detected from flocks sampled within the first few days of life. Astrovirus infections seemed to occur at an earlier age than other virus infections. Seldom was only one type of virus identified. Astrovirus + RVLV was the most frequently identified combination in diseased flocks.