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PubMed1997

Immune responses to individual rotavirus proteins following heterologous and homologous rotavirus infection in mice.

Serum and intestinal humoral immune responses to rotavirus proteins VP2, VP4, VP6, VP7, NSP2, and NSP4 were quantitatively compared in mice infected with a homologous murine rotavirus (EHPw) or a heterologous simian rotavirus (RRV). Viral protein-specific antibody responses were measured by an immunohistochemistry assay that uses recombinant baculovirus-expressed rotavirus proteins as antigens. In serum, IgG responses to VP6 were dominant and comparable in both RRV- and EHPw-infected groups, but responses to VP2, VP4, VP7, and NSP2 were higher in RRV infection. In feces, IgA responses to VP2, VP4, and VP6 were higher in EHPw-infected mice, but responses to VP7 and NSP2 were detected only in the RRV-infected group. These findings indicate that immune responses to homologous and heterologous rotavirus infection vary both quantitatively and qualitatively. Differences in humoral responses may play a role in the differences in protection induced following homologous or heterologous rotavirus infection.

Animals↗

PubMed1990

Rotavirus infection and rotavirus serum antibody in a cohort of children from Gaza observed from birth to the age of one year.

Rotaviruses were studied in a cohort of children from Gaza, during their first year of life. Surveillance was effected through visits to the local health clinic by parents and infants, and to a lesser extent, field workers' home visits. The observed rate of diarrhoea (all causes), and of rotavirus-associated diarrhoea was 1.25 and 0.1 episode per child-year, respectively. Of the 130 diarrhoea episodes in the cohort, only 6.9% were rotavirus-associated. Only nine (37.5%) of 24 children in whom rotavirus antigen was detected experienced a bout of diarrhoeal illness. However, 59.2% of cohort children had rotavirus serum antibodies by one year of age. The data indicate that rotavirus excretion in Gazan children tends to be asymptomatic during the first year of life.

Antibodies, Viral↗

PubMed1994

High prevalence of rotavirus infection among neonates born at hospitals in Delhi, India: predisposition of newborns for infection with unusual rotavirus.

Although rotavirus is the most common cause of diarrhea in children older than 3 months of age, neonatal infections, which are asymptomatic, have rarely been surveyed and have been identified in only a few discrete nosocomial outbreaks. After such a nosocomial outbreak of rotavirus infection among newborns at a hospital in Delhi, we screened infants born at five other nurseries in the immediate area to assess the prevalence of neonatal infections and to determine whether the unique neonatal rotavirus strain, 116E, previously identified in Delhi, was present in other settings. Infection was documented in 43 to 78% of hospitalized infants between 4 and 6 days of life born at five of the six hospitals. Infection with strains related to 116E were the most common, but other unusual strains and no strains common in the community were detected. In addition a shift in genotype was observed among specimens collected from two of these hospitals during a 2-year period. Our observation that neonatal rotavirus infections are more common than recognized previously would encourage the administration of rotavirus vaccines during the newborn period and suggests that the low efficacy of vaccines observed during trials in developing countries may be caused by early natural exposure of infants before immunization. The extraordinary predisposition of neonates for unusual rotavirus strains not commonly found in the community should encourage others to screen neonates for this infection, characterize the strains more fully and attempt to understand at a molecular level the unique relationship between the infecting strain type and the age of the host.

Feces↗

PubMed2000

Simian rhesus rotavirus is a unique heterologous (non-lapine) rotavirus strain capable of productive replication and horizontal transmission in rabbits.

Simian rhesus rotavirus (RRV) is the only identified heterologous (non-lapine) rotavirus strain capable of productive replication at a high inoculum dose of virus (>10(8) p.f.u.) in rabbits. To evaluate whether lower doses of RRV would productively infect rabbits and to obtain an estimate of the 50% infectious dose, rotavirus antibody-free rabbits were inoculated orally with RRV at inoculum doses of 10(3), 10(5) or 10(7) p.f.u. Based on faecal virus antigen or infectious virus shedding, RRV replication was observed with inoculum doses of 10(7) and 10(5) p.f.u., but not 10(3) p.f.u. Horizontal transmission of RRV to one of three mock-inoculated rabbits occurred 4-5 days after onset of virus antigen shedding in RRV-infected rabbits. Rabbits infected at 10(7) and 10(5), but not 10(3), p.f.u. of RRV developed rotavirus-specific immune responses and were completely (100%) protected from lapine ALA rotavirus challenge. These data confirm that RRV can replicate productively and spread horizontally in rabbits. In attempts to elucidate the genetic basis of the unusual replication efficacy of RRV in rabbits, the sequence of the gene encoding the lapine non-structural protein NSP1 was determined. Sequence analysis of the NSP1 of three lapine rotaviruses revealed a high degree of amino acid identity (85-88%) with RRV. Since RRV and lapine strains also share similar VP7s (96-97%) and VP4s (69-70%), RRV might replicate efficiently in rabbits because of the high relatedness of these three gene products, each implicated in host range restriction.

Amino Acid Sequence↗

PubMed1990

Prevention of human rotavirus infection with chicken egg yolk immunoglobulins containing rotavirus antibody in cat.

A study was made on the passive protection against rotavirus-induced diarrhea. Chickens were immunized with bovine rotavirus (serotype 1) and the egg yolk immunoglobulins containing a high titer anti-rotavirus neutralizing antibody (CEYI) was obtained. The CEYI was then orally administered to specific-pathogen-free cats, and the cats were infected with human rotavirus. The cats treated with the CEYI remained clinically healthy after challenge, whereas diarrhea occurred in the placebo-fed cats as control. Virus antigens were detected in feces in all the diarrheal cases in the placebo-fed cats but were only sporadically detected in the CEYI-fed cats. However, the cats were only protected against rotavirus infection by the presence in the gut at the time of infection of the antibody. These results suggested that continuous administration of the CEYI is capable of preventing children from diarrhea induced by human rotavirus infection and viral shedding.

Animals↗

PubMed1989

Noninfectious rotavirus (strain RRV) induces an immune response in mice which protects against rotavirus challenge.

We found that female adult mice parenterally inoculated with noninfectious rotavirus (simian strain RRV) developed virus-specific neutralizing antibodies in the serum; newborn mice from these dams were protected against RRV-induced gastroenteritis. In addition, mice parenterally inoculated with noninfectious RRV developed virus-specific cytotoxic T-lymphocyte precursors in the spleen. Replication of rotavirus in intestinal epithelial cells was apparently not required to induce rotavirus-neutralizing antibodies or rotavirus-specific cytotoxic T lymphocytes. Parenteral immunization of infants and young children with noninfectious rotaviruses may induce an immune response which protects against rotavirus challenge.

Animals↗

PubMed1990

Porcine rotaviruses antigenically related to human rotavirus serotypes 1 and 2.

Fecal samples from rotavirus-infected piglets were characterized by a serotyping enzyme-linked immunosorbent assay (ELISA) by using monoclonal antibodies (MAbs) specific to human serotypes 1, 2, 3, and 4 (D. O. Matson, M. K. Estes, J. W. Burns, H. B. Greenberg, K. Taniguchi, and S. Urasawa, submitted for publication). Rotavirus in 19 of 25 specimens tested from two herds of pigs from Buenos Aires province, Argentina, were classified antigenically as follows: one serotype 1, four serotype 2, two serotype 3, and no serotype 4. Six specimens reacted with both serotype 1 and 2 MAbs, and viruses in six specimens probably belonged to other serotypes because they reacted only with a VP7 common epitope MAb. Two porcine rotavirus fecal samples found to contain both serotype 1 and 2 viruses by the MAb-based test and one found to contain a serotype 2 virus were grown in tissue culture. When plaque-purified preparations of these tissue culture-adapted viruses were analyzed in the serotyping ELISA, the C60 and C86 preparations reacted only as serotype 1 viruses, indicating that the original fecal samples, which showed multiple VP7 reactivities, were heterogeneous and apparently contained two types of viruses. Testing of plaque-purified C134 virus confirmed its serotype 2 reactivity. The MAb-based serotype designations of these viruses also were confirmed by using a neutralization immunoperoxidase focus reduction assay. This is the first report of the occurrence of serotype 1 and 2 rotaviruses in animals. The MAbs originally developed to serotype human rotaviruses can be utilized to type animal rotaviruses.

Animals↗

PubMed1998

Enzyme-linked immunosorbent assay based on recombinant human group C rotavirus inner capsid protein (VP6) To detect human group C rotaviruses in fecal samples.

A recent study showed that 43% of a population in the United Kingdom were seropositive for group C rotavirus. The higher than expected incidence may be due to limited diagnosis of acute human group C rotavirus infections because no routine test is available. Human group C rotavirus infections are routinely diagnosed by electron microscopy (EM) and a negative group A rotavirus enzyme-linked immunosorbent assay (ELISA) result. An antigen-detection ELISA was developed with hyperimmune antibodies raised to human group C rotavirus recombinant VP6 (Bristol strain) expressed in insect cells. The assay was used to screen fecal samples to determine the prevalence of group C rotavirus infection. Samples positive by ELISA were confirmed by EM, polyacrylamide gel electrophoresis of double-stranded RNA, or detection of the VP6 gene by reverse transcription-PCR. Retrospective analysis indicated a 1 to 2% detection rate of positivity among samples from patients with acute diarrhea.

Animals↗

PubMed2002

Inhibition of rotavirus replication by a non-neutralizing, rotavirus VP6-specific IgA mAb.

Rotaviruses are the leading cause of severe diarrheal disease in young children. Intestinal mucosal IgA responses play a critical role in protective immunity against rotavirus reinfection. Rotaviruses consist of three concentric capsid layers surrounding a genome of 11 segments of double-stranded RNA. The outer layer proteins, VP4 and VP7, which are responsible for viral attachment and entry, are targets for protective neutralizing antibodies. However, IgA mAb's directed against the intermediate capsid protein VP6, which do not neutralize the virus, have also been shown to protect mice from rotavirus infection and clear chronic infection in SCID mice. We investigated whether the anti-VP6 IgA (7D9) mAb could inhibit rotavirus replication inside epithelial cells and found that 7D9 acted at an early stage of infection to neutralize rotavirus following antibody lipofection. Using electron cryomicroscopy, we determined the three-dimensional structure of the virus-antibody complex. The attachment of 7D9 IgA to VP6 introduces a conformational change in the VP6 trimer, rendering the particle transcriptionally incompetent and preventing the elongation of initiated transcripts. Based on these observations, we suggest that anti-VP6 IgA antibodies confers protection in vivo by inhibiting viral transcription at the start of the intracellular phase of the viral replication cycle.

Animals↗

PubMed1983

Epidemiologic background for the need of rotavirus vaccine in Finland. Preliminary experience of RIT 4237 strain of live attenuated rotavirus vaccine in adults.

Epidemiologic evidence from Finland indicates a dramatic change in the seasonal pattern of acute diarrhoea over the past 30 years. While in the 1950's the majority of cases occurred in late summer the seasonal peak in the 1970's was in winter and spring, coinciding with the prevalence of rotavirus infections. It is not possible to determine retrospectively the aetiologic agents involved in the summer diarrhoea, but EPEC may have been one of them, as EPEC are quite rare in Finland today compared to the 1950's. Another change over the time period is a shift in the age distribution of acute diarrhoea from neonates towards older infants. Rotavirus is today associated with approximately 50% of the cases of acute diarrhoea in children in Finland. Based on experience in one Central Hospital it was estimated that the treatment of rotavirus infections may require some 7300 hospital days in Finland annually, which figure is comparable to that of mumps. As a recent cost-benefit analysis in Finland indicated that a mumps vaccination programme would be economically quite efficacious, the same could be assumed to be true for rotavirus vaccination, provided that an effective and safe vaccine was available. In a preliminary trial of RIT 4237 strain of live attenuated rotavirus vaccine in 20 healthy adult volunteers no clinical symptoms and no excretion of vaccine virus were observed. Rotavirus ELISA antibody booster response was found in 1/20 vaccinees.

Adult↗

PubMedDate not supplied

Annual rotavirus epidemic patterns in North America. Results of a 5-year retrospective survey of 88 centers in Canada, Mexico, and the United States. Rotavirus Study Group.

Rotavirus is the major cause of severe diarrhea in children. A recent study of hospitalizations for diarrhea in the United States suggested that the annual rotavirus epidemic may follow a regional sequence from west to east. As part of a program to establish active surveillance of rotavirus prior to the introduction of vaccines, we obtained 5 years of retrospective data on rotavirus detections from 88 centers throughout North America. Analysis of 34,644 detections indicates that the peak of the annual rotavirus epidemic occurs first in Mexico and the Southwest of the United States in late fall, goes systematically across the continent in the winter, and ends in the Northeast United States and the Maritime Provinces of Canada in the spring. When detections are grouped by region, onset of the epidemic follows the same regional sequence as the peak. To our knowledge, this is the only description of a repetitive geographic sequence for the seasonal epidemic activity of a viral agent. Further studies are indicated to determine whether climate, features of the virus itself, or other factors are responsible for this apparently unique pattern. A system of active surveillance can use this pattern to detect natural alterations in the epidemic behavior of rotavirus and to assess the impact of vaccines.

Canada↗

PubMed1995

Sequence analysis of cDNA for the VP6 protein of group A avian rotavirus: a comparison with group A mammalian rotaviruses.

cDNA corresponding to the genomic segment 6 of avian rotavirus strain PO-13, which has group A common and subgroup I antigens, but does not hybridize in Northern blots with RNA probes from group A mammalian rotaviruses, was cloned and sequenced. When the deduced amino acid sequence was compared between strain PO-13 and eight group A mammalian rotaviruses, the extent of homology ranged from 73-75%. An alignment of the amino acid sequences allowed us to identify three amino acids (Positions 120, 317 and 350) that may contribute to determining the subgroup epitopes. A phylogenetic tree constructed on the basis of nucleotide substitutions in the VP6 gene of nine rotaviruses strongly suggests that the avian rotavirus is an ancestral prototype of mammalian rotaviruses.

Amino Acid Sequence↗

PubMed1991

Sequence of the VP7 gene of chicken rotavirus Ch2 strain of serotype 7 rotavirus.

The gene that encodes the VP7 protein of the Ch2 strain of group A chicken rotavirus (serotype G7) was sequenced, and its deduced amino acid sequence analyzed. The gene is 1067 bp in length and contains a single long open reading frame of 987 nt, capable of encoding a protein of 329 amino acids. Amino acid homology of the chicken rotavirus VP7 to the corresponding protein of rotaviruses representing each of the other twelve G serotypes ranged from 58 to 63%. In addition, the VP7 protein of the Ch2 strain contains a unique amino acid sequence in variable regions VR5 (A), VR7 (B), or VR8 (C), which is consistent with previous studies indicating that these three regions are involved in G serotype specificity. The VP7 protein had amino acid homology of 19 or 33% with that of groups B (ADRV) or C (Cowden) rotavirus strains, respectively. Attempts to produce reassortants in vivo or in vitro between the Ch2 strain and strains belonging to group A or C rotavirus were unsuccessful. The low level of nucleotide identity in the 5' end noncoding region of the VP7 gene between the Ch2 and the group A or C rotaviruses may account for this failure.

Amino Acid Sequence↗

PubMed1991

Sequence conservation of gene 8 between human and porcine group C rotaviruses and its relationship to the VP7 gene of group A rotaviruses.

cDNA libraries from porcine group (Gp) C rotavirus strain Cowden and a human Gp C rotavirus strain were generated. The complete nucleotide sequence of gene 8 from the Cowden strain was determined from gene 8-specific clones and viral transcript RNA. A full-length gene 8 clone was generated from the human Gp C virus by polymerase chain reaction (PCR) using primers deduced from the 3' and 5' ends of the Cowden strain gene 8, and the sequence of the human Gp C gene 8 was determined from this clone and gene 8 clones in the cDNA library. The gene 8 from the Cowden or the human Gp C strain is 1063 nucleotides in length and contains a long open reading frame beginning at the 49th nucleotide from the 5' end and terminating with a stop codon 16 bases from the 3' end. The encoded protein contains 332 amino acids (predicted molecular weight of 37.3 kDa) with two potential N-linked glycosylation sites in the porcine strain and three in the human strain. The polypeptide products derived from in vitro translation of the transcript RNA generated from a porcine gene 8 clone containing the entire open reading frame were analogous in size with the Gp A VP7. The gene 8 of porcine and human Gp C rotaviruses exhibited considerable nucleotide and deduced amino acid sequence identity (83.8 and 88.0%, respectively). Comparison of the Gp C gene 8 protein sequence with the VP7 protein of Gp A rotavirus revealed structural similarities, although the overall amino acid identity was low (less than 30%). These data suggest that the gene 8 of the porcine or human Gp C rotavirus encodes a protein corresponding to the VP7 outer capsid glycoprotein of Gp A rotaviruses and that the eighth gene is highly conserved in the porcine and human Gp C strains examined in this study.

Amino Acid Sequence↗

PubMed2005

Sequence analysis of the VP7 and VP4 genes identifies a novel VP7 gene allele of porcine rotaviruses, sharing a common evolutionary origin with human G2 rotaviruses.

During an epidemiological survey encompassing several porcine herds in Saragoza, Spain, the VP7 and VP4 of a rotavirus-positive sample, 34461-4, could not be predicted by using multiple sets of G- and P-type-specific primers. Sequence analysis of the VP7 gene revealed a low amino acid (aa) identity with those of well-established G serotypes, ranging between 58.33% and 88.88%, with the highest identity being to human G2 rotaviruses. Analysis of the VP4 gene revealed a P[23] VP4 specificity, as its VP8* aa sequence was 95.9% identical to that of the P14[23],G5 porcine strain A34, while analysis of the VP6 indicated a genogroup I, that is predictive of subgroup I specificity. Analysis of the 10th and 11th RNA segments revealed close identity to strains of porcine and human origin, respectively. The relatively low overall aa sequence conservation (<89% aa) to G2 human rotaviruses, the lack of N-glycosylation sites that are usually highly conserved in G2 rotaviruses, and the presence of several amino acid substitutions in the major antigenic hypervariable regions hampered an unambiguous classification of the porcine strain 34461-4 as G2 serotype on the basis of sequence analysis alone. The identification of a borderline, G2-like, VP7 gene allele in pigs, while reinforcing the hypotheses of a tight relationship in the evolution of human and animal rotaviruses, provides additional evidence for the wide genetic/antigenic diversity of group A rotaviruses.

Alleles↗

PubMed1992

Outbreaks of summer rotavirus linked to laboratory practices. The National Rotavirus Surveillance System.

In temperate regions rotavirus diarrhea is a disease of the cooler months of the year, but little is known about its patterns in the summer. We report on the first year of national surveillance of rotavirus, during which we actively investigated patterns of summer activity. We obtained data on rotavirus testing from 85 laboratories in 48 states, conducted a survey of their testing practices and retested for confirmation positive specimens from laboratories reporting high rates of positivity during the summer. During 1989 participating laboratories reported 4011 specimens tested for rotavirus during July and August, of which 436 (11%) were said to be positive. Most laboratories reported low rates of positivity during these months (median percent positive, 3), but five had very high rates of summer positivity (> 30%). These five laboratories were geographically separated, and neighboring laboratories showed little rotavirus activity. Positive specimens submitted by four of these centers with high rates of summer rotavirus could not be confirmed. A survey of laboratory methods found one commercial assay (TestPack) and two laboratory practices (failure to use controls and involvement of more than six technicians in the testing process) to be associated with high rates of summer positivity. Moderate rates of positivity (11 to 30%) were fond frequently in the southwest during July and August; reference testing of specimens from these laboratories confirmed positivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Laboratory Techniques↗

PubMed2000

Etiology of community-acquired pediatric viral diarrhea: a prospective longitudinal study in hospitals, emergency departments, pediatric practices and child care centers during the winter rotavirus outbreak, 1997 to 1998. The Pediatric Rotavirus Epidemiology Study for Immunization Study Group.

OBJECTIVE: To determine the viral etiology of community-acquired diarrhea in children admitted to hospitals and presenting in emergency departments, pediatric practices and child care centers from November 1, 1997, to June 30, 1998. STUDY DESIGN: Children with diarrhea were identified in a prospective multisite cohort study and analyzed according to age, gender and duration of hospitalization. Stools were tested for rotavirus by enzyme immunoassay and for all other enteric viruses by electron microscopy. RESULTS: Of the 2524 children identified with diarrhea, stools of 1386 (55%) were tested by enzyme immunoassay for rotavirus, and of these 1365 (54%) were screened by electron microscopy for all identifiable enteric viruses. Rotavirus was found in 32% (n = 437), adenovirus in 4% (n = 55), torovirus in 3% (n = 44), Norwalk-like viruses in 2% (n = 25) and astrovirus (n = 14) and calicivirus (n = 7) in fewer than 1% of the specimens tested. The proportion of rotavirus was significantly higher in children 12 to 23 months of age (43% of tested stools, n = 159) and 24 to 35 months of age (38% of tested stools, n = 64) (P < 0.001) than in any other age group. Toroviruses were found to approximately the same extent in children > or =36 months of age (6% of tested stools, n = 19) as those <36 months of age. Rotavirus (36% of tested stools, n = 375, P < 0.0005) and torovirus (4% of tested stools, n = 43, P < 0.004) were most often found in hospitalized patients. In contrast Norwalk-like viruses (P < 0.001) and astroviruses (P < 0.01) were more commonly detected in specimens from patients who presented to physicians' offices and who were symptomatic for gastroenteritis in child care centers. CONCLUSION: This study demonstrates that although all known gastroenteritis viruses were diagnosed in symptomatic children, rotavirus was the etiologic agent in most cases of diarrhea managed in the community and in the hospital.

Child Day Care Centers↗

PubMed1992

A VP4 sequence highly conserved in human rotavirus strain AU-1 and feline rotavirus strain FRV-1.

The primary amino acid sequence of the VP4 proteins of human rotavirus strain AU-1 and feline rotavirus strain FRV-1 was deduced from nucleotide sequence analysis of full-length genome segment 4 cDNAs produced by a combined reverse transcription-polymerase chain reaction. The VP4 genes were 2359 nucleotides in length and contained one long open reading frame capable of encoding a protein of 775 amino acids. Strain AU-1 and FRV-1 VP4s were 98.8% similar at both the nucleotide sequence and amino acid level. Given that most of the genome segments of strains AU-1 and FRV-1 formed hybrids under stringent hybridization conditions, the relationship between their VP4 gene sequences is best explained by feline rotavirus being transmitted to human hosts as whole virions relatively recently. Of added interest is that AU-1 and FRV-1 VP4 both exhibit high degrees of similarity (96.0% nucleotide identity and 97.2 to 97.5% amino acid identity) with serotype G1 human rotavirus strain K8 VP4, which is distinct from any other sequenced VP4 allele. This suggests that strain K8 VP4 was derived by natural gene reassortment from a feline rotavirus or a strain AU-1-like human rotavirus.

Amino Acid Sequence↗