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PubMed1988

Immune response of pregnant heifers and cows to bovine rotavirus inoculation and passive protection to rotavirus infection in newborn calves fed colostral antibodies or colostral lymphocytes.

The efficacy of an adjuvanted bovine rotavirus vaccine in pregnant cattle (15 heifers and 2 cows) was studied. Each of 4 animals was inoculated IM at 8, 5, and 2 weeks before parturition with a water-in-oil emulsion containing live purified bovine rotavirus, mineral oil, and a mannide oleate compound. Four other animals were treated identically, except that muramyl dipeptide was added to the virus preparation. Five additional animals were inoculated orally at the same time intervals with adjuvant-free viral suspension, and 4 other pregnant animals inoculated only with buffer served as uninoculated controls. Kinetic studies of the specific immune responses were determined by quantification of the rotavirus-neutralizing antibodies and by a rotavirus lymphocyte stimulation test in vitro. Results showed that only the emulsions induced marked enhancement of rotavirus antibody titers in the serum, colostrum, and milk of inoculated cows. Colostral and milk lymphocytes isolated from these cows had a positive in vitro proliferative response to rotavirus stimulation, which lasted at least 21 days after parturition. The values of the stimulation index obtained with the colostral/milk lymphocytes were higher than those of the blood lymphocytes, reflecting increased lymphocyte activity in the colostrum/milk. However, addition of muramyl dipeptide to the emulsion preparation did not exert any potentiating effect on the immune response to rotavirus. Calves fed for the first 5 days after birth with a rotavirus-immune cell-free colostrum supplement were protected from a rotavirus challenge exposure on the third day after birth. Virus was not detectable in their feces.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗

PubMed1995

Association of human rotavirus infection and intestinal rotavirus-specific immunoglobulin A in children with diarrhoea.

The purpose of this study was to determine the role of intestinal specific rotavirus IgA antibody in protection against diarrhoea due to rotavirus infection. Stool from children aged below 5 years with diarrhoea who reported to the Paediatric Observation Ward, Kenyatta National Hospital were examined for micro-organisms and IgA antibody. Specific rotavirus IgA antibody and antigen were determined using enzyme linked immunosorbent assay technique. Out of 153 stool specimens, 22% (34/153) were positive for rotavirus antigen and 15% (23/153) had IgA specific antibody to rotavirus. Children with specific IgA to rotavirus had no rotavirus except in two cases (p < 0.05). There was no difference in levels of specific IgA antibody between normal and malnourished children (p = 0.4). It is probable that intestinal specific IgA to rotavirus protects children against rotavirus diarrhoea.

Antibodies, Viral↗

PubMed2000

Hospitalization for community-acquired, rotavirus-associated diarrhea: a prospective, longitudinal, population-based study during the seasonal outbreak. The Greater Toronto Area/Peel Region PRESI Study Group. Pediatric Rotavirus Epidemiology Study for Immunization.

OBJECTIVES: To determine the age-specific hospitalization rate for rotavirus-associated diarrhea in Canadian children during the seasonal outbreak, and to characterize children and their households, for assessment of the need for a rotavirus vaccine. DESIGN: Prospective multisite cohort study. SETTINGS AND PARTICIPANTS: Children with an admission diagnosis of diarrhea admitted to 18 hospitals serving 132 study census tracts of a major urban region, from November 1, 1997, through June 30, 1998. Prospective centralized testing of stools was performed; research nurses administered a follow-up questionnaire to parents. MAIN OUTCOME MEASURE: Age-specific diarrhea and rotavirus-associated hospitalization rates. RESULTS: Of 224160 children younger than 5 years, the diarrhea hospitalization rate was 4.8 in 1000 (n = 1086) during the seasonal epidemic. Based on testing of 65% of the hospitalized children, the rotavirus-associated diarrhea hospitalization rate was 1.3 in 1000; the cumulative incidence to 5 years of age was 1 in 160. Rotavirus-associated diarrhea was reported in 37% of the 1001 hospitalized children undergoing testing inside and outside of the census tracts; in children aged 6 to 35 months, this rose to more than 70% during April and May. Ages of children with rotavirus-associated diarrhea were 0 to 2 months (2%), 3 to 5 months (5%), 6 to 23 months (60%), 24 to 35 months (15%), and 36 months or older (19%). Of children aged 0 to 5 and 6 to 11 months, 4 (19%) of 21 and 6 (10%) of 59, respectively, had been born prematurely; 20 (24%) of 83 younger than 1 year were breastfed at the time of illness. Of children younger than 36 months, 77% were cared for in their homes; 13%, in family day care homes; and 8%, in child care centers. The mean (+/- SD) duration of rotavirus hospitalization based on hospital records and parental questioning was 2.4 +/- 1.7 and 3.1 +/- 1.6 days, respectively; it was significantly longer (P < or = .001) in children with an underlying medical condition. One child required intensive care unit hospitalization. Diarrhea occurred concurrently in 74% of household contacts younger than 3 years; 38%, aged 3 to 18 years; and 29%, older than 18 years. Seventy-six percent of parents were married. Household incomes in Canadian dollars in the 81% reporting were less than $20000 in 20%, $20000 to $60000 in 44%, and greater than $60000 in 36%. Ethnicity was reported as 53% white, 15% black, 10% Asian, 12% East Indian, and 11% other. CONCLUSIONS: Based on testing of 65% of children with diarrhea, rotavirus resulted in hospitalization in a minimum of 1 in 160 children by 5 years of age during the seasonal outbreak. Had 100% of young children with diarrhea undergone testing, the extrapolated cumulative incidence of rotavirus-associated diarrhea by 5 years of age may have been 1 in 106.

Acute Disease↗

PubMed2001

Complete nucleotide sequence of a group A avian rotavirus genome and a comparison with its counterparts of mammalian rotaviruses.

The nucleotide sequences encoding four structural proteins (VP1-4) and six nonstructural proteins (NSP1-6) of avian rotavirus PO-13 were determined. Based on the results of earlier sequencing studies [Ito et al., 1995, Sequence analysis of cDNA for the VP6 protein of group A avian rota viruses. Arch. Vriol. 140, 605-612; Rohwedder et al., 1997, Chicken rotavirus Ch-1 shows a second type of avian VP6 gene, Virus Genes 15, 65-71; Rohwedder et al., 1997, Bovine rotavirus 993/83 shows a third subtype of avian VP7 protein, Virus Genes 14, 147-151], determination of PO-13 genome sequence has been completed. The PO-13 genome is 18845 nucleotides in length. It is 290 nucleotides longer than the genome of SA11. The amino acid sequence homology between PO-13 and mammalian rotaviruses ranged from 76-77% (VP1) to 16-18% (NSP1). The features of gene and amino acid sequence were compared with those of the corresponding protein of mammalian rotaviruses. Based on results of the phylogenetic analyses of NSP1, we speculate that an ancestral rotavirus could have separated into groups A, B and C rotaviruses at an early evolutionary stage and that group A rotavirus separated into mammalian and avian rotaviruses with host evolution.

Amino Acid Sequence↗

PubMed1995

Rotavirus shedding in feces of gnotobiotic calves orally inoculated with a commercial rotavirus-coronavirus vaccine.

The purpose of this study was to monitor by negative stain electron microscopy the shedding of rotavirus in the feces of gnotobiotic calves orally inoculated with a commercial modified live bovine rotavirus-bovine coronavirus vaccine. Negative stain electron microscopic examination detected vaccine rotavirus in only 1 of 41 daily fecal specimens collected from 3 gnotobiotic calves during the 2 weeks following oral inoculation with a US Department of Agriculture-licensed modified live bovine rotavirus-bovine coronavirus vaccine. In contrast, rotavirus was demonstrable by the same negative stain electron microscopic examination procedure in 17 of 19 fecal specimens collected from diarrheic gnotobiotic or colostrum-deprived calves during the first 8 days after inoculation with virulent bovine rotavirus field strains. Rotavirus was also detected by this procedure in 4 enzyme-linked immunosorbent assay positive fecal specimens collected from naturally-infected diarrheic dairy calves. These results suggest that fecal shedding of vaccine rotavirus demonstrable by electron microscopic examination is uncommon following oral inoculation of calves with the bovine rotavirus-bovine coronavirus vaccine.

Animals↗

PubMed1988

Protective effect of WC3 vaccine against rotavirus diarrhea in infants during a predominantly serotype 1 rotavirus season.

We used a double-blind, placebo-controlled trial to study the efficacy of WC3 rotavirus vaccine administered to 104 infants (ages, three to 12 months) before the rotavirus season. Forty-nine infants received vaccine; 55 received placebo. Rotavirus disease during this season was predominantly caused by a serotype 1 strain. In placebo recipients there were 14 cases of rotavirus diarrhea (attack rate, 25%); 11 were moderate to severe (attack rate, 20%). Vaccinees experienced only three cases of rotavirus disease (attack rate, 6.1%), all mild. When all cases (whether associated with rotavirus or not) of clinically significant diarrhea (CSD) were evaluated, WC3 vaccine provided statistically significant (P less than .01) protection against the total number of episodes of CSD and reduced the number of days of CSD-associated diarrhea, vomiting, fever, or illness. Seventy-one percent of the WC3-vaccinated infants had serum antibody responses to the vaccine. The 14 placebo recipients who experienced natural disease predominantly had antibody responses to serotype 1. Sera taken after the rotavirus season revealed a nearly identical rate (40%) of natural rotavirus infection in the vaccinated and placebo groups.

Antibodies, Viral↗

PubMed1990

Immune protection of infants against rotavirus gastroenteritis by a serotype 1 reassortant of bovine rotavirus WC3.

The safety and protective efficacy of a serotype 1 reassortant of bovine rotavirus WC3, disignated strain WI79-9, was evaluated in a double-blind placebo-controlled trial. Rotavirus reassortant WI79-9 contains a gene segment 9 coding for the surface structural protein vp7 of a human serotype 1 rotavirus, with all other gene segments derived from WC3 rotavirus, which had previously been shown to be safe and immunogenic in infants. Infants 2-11 months of age were given two doses of vaccine (10(7.3) plaque-forming units/dose) or of placebo 28 days apart. Adverse reactions to the vaccine were not detected. The incidence of serum plaque reduction neutralization antibody responses to two doses of vaccine was serotype 6, 97%; serotype 3, 68%; and serotype 1, 22%. Active surveillance during the subsequent rotavirus season revealed 8 cases of rotavirus gastroenteritis in 39 placebo control infants and no cases in 38 WI79-9 vaccine recipients (protection = 100%, P = .003). Six cases of rotavirus gastroenteritis were caused by type 1 and two by type 3 virus. Although vaccination with WI79-9 affected only the incidence of rotavirus gastroenteritis, the vaccinated infants exhibited a significantly reduced incidence of total days of diarrhea, fever, and illness associated with gastroenteritis in general.

Antibodies, Viral↗

PubMed1991

Efficacy of two doses of RIT 4237 bovine rotavirus vaccine for prevention of rotavirus diarrhoea.

Candidate oral bovine rotavirus vaccine RIT 4237 or placebo was given to 252 Finnish infants at birth and at 7 months of age. No vaccine-associated reactions were observed. Primary rotavirus ELISA IgM responses were detected in 36% of the infants after the first vaccination; after the second dose 68% of the vaccinees were seropositive for rotavirus ELISA IgG antibody. The infants remained in clinical follow-up over two rotavirus epidemic seasons (total 28 months). Counted from child years in follow-up the overall vaccine protection rate was 43%. The clinical severity of rotavirus episodes was assessed using a numerical score 0-20. Vaccine protection rate for cases with a score greater than or equal to 7 was 57% and for cases with a score greater than or equal to 11 it was 89%. It is concluded that vaccination with a bovine rotavirus vaccine at birth and at 7 months of age, with the second dose given shortly before rotavirus epidemic season, protects infants against moderately severe and severe rotavirus diarrhoea in the first 2 years of life.

Antibodies, Anti-Idiotypic↗

PubMed2005

Predominance of rotavirus G9 genotype in children hospitalized for rotavirus gastroenteritis in Belgium during 1999-2003.

BACKGROUND: Group A rotavirus genotypes G1, G2, G3 and G4 are the main etiological agents of infantile diarrhea. The G9 rotavirus has recently emerged as a fifth important genotype all over the world. OBJECTIVE: To characterize the VP7 gene of group A rotaviruses from gastroenteritis patients admitted to the Gasthuisberg University Hospital, Leuven, Belgium, during 1999-2003. STUDY DESIGN: Rotavirus antigen was detected in stool specimens using an enzyme immunoassay. G-typing was performed by reverse transcriptase polymerase chain reaction (RT-PCR) amplification and sequencing of the complete VP7 gene. RESULTS: The genotype distribution varied markedly over the four rotavirus years in Belgium. In the 1999-2000 rotavirus year, G1 was the predominating type (72%), and G9 was present in 5% of the rotavirus-positive patients. In the 2000-2001 and 2002-2003 years, G9 appeared as the dominating strain (45% and 53%, respectively). In the 2001-2002 year, between two G9 epidemic years, G1 was dominating (66%) but G9 was still present in 24%. All the G9 isolates were combined with P[8] and shared a high gene sequence similarity (<3% sequence divergence on the nucleotide and amino acid level). Phylogenetic analysis of the VP7 genes revealed that our Belgian G9 strains clustered together with recent G9 strains from all over the world, distinct from the prototype G9 strains isolated in the 1980s. CONCLUSION: Our study indicates that although the first introduction of G9 isolates in the Belgian population was recorded in 1997, G9 strains were able to establish themselves quickly as the predominant genotype. The emergence of G9 as an important pathogen in both developing as industrialized countries necessitates the urgent consideration of the G9 moiety in rotavirus vaccines.

Antigens, Viral↗

PubMed1985

Clinical efficacy of the RIT 4237 live attenuated bovine rotavirus vaccine in infants vaccinated before a rotavirus epidemic.

In a randomized, double-blind, placebo-controlled trial, 331 infants aged 6 to 12 months received orally, at an interval of 1 month, either two doses of live attenuated bovine rotavirus vaccine strain RIT 4237 or equivalent placebo. The vaccinations were carried out during September to November, a non-rotavirus season; only three cases of rotavirus diarrhea occurred in the study group before the vaccinations were completed. During the epidemic season from December to May, 31 patients with clinically significant rotavirus diarrhea required therapy. Five of these were among the 168 vaccine recipients, and 26 among the 160 placebo recipients (P less than 0.001), giving a vaccine protection rate of 82%. The incidence of clinically significant diarrhea from all causes was reduced by 76% in the vaccinees. As determined by an enzyme immunoassay antibody test with homologous virus antigen, seroconversion after vaccination was obtained in 53% of the initially seronegative infants. Clinical protection correlated well with seroconversion, but the vaccinees who failed to seroconvert also had less rotavirus diarrhea than the placebo recipients, suggesting that immunity may be mediated by factors other than serum EIA antibody. Seventeen of the 23 rotavirus isolates in the epidemic season that were typed were of serotype 1, two were of serotype 2, and four were of serotype 3. The protection rates against clinically significant diarrhea were 72%, 100%, and 100% for serotypes 1, 2, and 3, respectively. We conclude that epidemic infantile winter diarrhea associated with human rotaviruses can be significantly reduced by vaccination with the live attenuated RIT 4237 bovine rotavirus vaccine before the epidemic season.

Clinical Trials as Topic↗

PubMed2003

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.

Animals↗

PubMed1989

Effects of antibody to rotavirus on protection of adults challenged with a human rotavirus.

Effects of preinoculation rotavirus antibody titers on the probability of infection and illness were evaluated in adults challenged orally with different doses of a virulent human rotavirus (CJN strain). Preinoculation titers considered were serum neutralizing antibody, serum rotavirus IgA, serum rotavirus IgG, jejunal neutralizing antibody, jejunal rotavirus IgA, and stool rotavirus IgA. Doses of virus of either 9 x 10(1) or 9 x 10(3) focus-forming units were administered to 19 subjects each. Twenty-six were infected; 15 experienced illness. The probability of either outcome was unrelated to dose. Stool rotavirus IgA titers could not be correlated to either infection or illness, but the mean titers of the other five antibodies were significantly or nearly significantly lower in subjects infected or ill, when compared with those negative for either outcome. When analyzed by stepwise logistic regression, only serum rotavirus IgG remained significantly (P = .005) related to the probability of infection, and only jejunal neutralizing antibody remained significantly (P = .01) related to the probability of illness.

Adult↗

PubMed2004

A rotavirus vaccine for prophylaxis of infants against rotavirus gastroenteritis.

The need for safe and effective vaccines to reduce morbidity and mortality caused by rotavirus gastroenteritis in children is well-known. A live attenuated monovalent rotavirus vaccine (Rotarix) containing human rotavirus strain RIX4414 of G1P1A P[8] specificity is being developed to meet the global need. An overview of RIX4414 trials in developed and developing settings is presented for 3 selected trials conducted in Finland (pilot study), Latin America (Brazil, Mexico and Venezuela) and Singapore involving 5024 infants. The vaccine was well-tolerated, with no increase in any solicited symptoms as compared with the placebo. After 2 doses, 61-91% of vaccinated infants developed rotavirus-specific IgA antibodies. There was no interference with immunogenicity of coadministered routine pediatric vaccines. Rotarix significantly reduced rotavirus gastroenteritis episodes and rotavirus-related hospitalizations in vaccinated infants compared with placebo recipients (P < 0.05). Vaccine efficacy was observed against severe rotavirus gastroenteritis caused by G1 and non-G1 types including the emerging G9 type (P < 0.05) in Latin America. These results show prospects for widespread use of Rotarix to reduce rotavirus disease burden and warrant continued worldwide evaluation.

Clinical Trials as Topic↗

PubMed2002

Detection and characterization of rotavirus G and P types from children participating in a rotavirus vaccine trial in Belém, Brazil.

This study sought the characterization of rotaviruses in a trial with a tetravalent rhesus-human rotavirus vaccine in Belém, Brazil in children who received three doses of vaccine or placebo in the 1st, 3rd and 5th months of life. Rotavirus electropherotypes, subgroups, G serotypes, G, [P] and [P], G genotypes were determined in 93.3%, 95.9%, 93.3%, 73.3%, 95.5% and 92.2% of isolates, respectively. Serotypes G1, G2 and G4 were detected in 58.9%, 30% and 4.4% of the cases, respectively. Rotavirus genotype G5 was detected for the first time in Northern region in 4.4% of the infections. Rotavirus genotypes P[8], P[4], P[6] and P[8 + 6] were detected in 54.5%, 26.7%, 12.2%, and 2.2% of the cases, respectively. The predominant genotypes were P[8], G1 and P[4], G2 with 53% and 26.6% of the infections, respectively. Unusual strains accounted for 20.5% including P[4], G1, P[6], G1, P[6], G4, P[6], G5, P[8], G2, P[8], G5. Mixed infections involving P[8 + 6], G2 and P[8 + 6], G1 were also noted. The neonatal P[6] strains associated with diarrhea were detected among children aged 9-24 months. To our knowledge, this study represents the first in Brazil to analyse, on molecular basis, rotavirus genotypes from children participating in a rotavirus vaccine trial. These results are of potential importance regarding future rotavirus vaccination strategies in Brazil.

Brazil↗

PubMed2004

The epidemiology of rotavirus diarrhea in Latin America. Anticipating rotavirus vaccines.

OBJECTIVE: To assess the disease burden and characterize the epidemiology of rotavirus diarrhea in Latin America. METHODS: We conducted a literature review of studies of children < 5 years of age who were hospitalized or seen as outpatients for diarrhea and for whom rotavirus was sought as the etiologic agent of the diarrhea. This review included inpatient and outpatient studies published since 1998 that included at least 100 children and reported surveillance activities lasting at least 12 consecutive months. RESULTS: A total of 18 inpatient and 10 outpatient studies met the criteria for inclusion in this review. Rotavirus was detected in a median of 31% of inpatients (range, 16%-52%) and 30.5% of outpatients (range, 4%-42%). The median detection rate was higher in studies that used an enzyme-linked immunosorbent assay (ELISA) (inpatients 38%, outpatients 33%) versus less sensitive methods of detection. The age distribution of rotavirus disease varied among countries, with 65%-85% of children hospitalized in the first year of life. Most countries had rotavirus admissions year round, and rotavirus generally exhibited a winter seasonal peak in both temperate and tropical climates. CONCLUSIONS: The heavy burden of disease attributable to rotavirus in Latin America suggests that vaccines currently being tested could have considerable impact in preventing hospitalizations, clinic visits, and deaths. The findings of the young age distribution of patients highlight the importance of early immunization for the success of a vaccine program. The data suggest that future surveillance for rotavirus diarrhea in Latin America should use a standardized surveillance protocol with an ELISA for detection. Data from surveillance studies will be critical to monitor the impact of the future introduction of vaccines.

Age Distribution↗

PubMed1993

Sequence analysis of group B rotavirus gene 1 and definition of a rotavirus-specific sequence motif within the RNA polymerase gene.

The complete nucleic acid sequence was determined for the largest genomic segment of the IDIR strain of group B rotavirus and compared with RNA polymerase genes of rotavirus groups A and C as well as other RNA viruses. IDIR gene 1 contained 3509 bases with a single, long open reading frame which encoded a deduced polypeptide of 1159 amino acids (MW = 131.6 kDa; pl 8.851). The deduced amino acid sequence of IDIR gene 1 shared 50% similar sequences and 27.6% identical sequences with VP1 of the RF strain of group A rotavirus. IDIR gene 1 also contained 45.4% similar and 26.5% identical amino acid sequences in comparison with gene 1 of the Cowden strain of group C rotavirus. Amino acids 643-689 of IDIR gene 1 corresponded to the conserved viral RNA polymerase domains, "SG . . . T . . . NS . . N" and "GDD." Within these domains, group A, B, and C rotaviruses displayed substantial homologies that were not shared with other RNA viruses. These sequences indicated the presence of highly conserved structural or functional components among groups of rotaviruses which were otherwise quite heterogeneous. The identification of rotavirus-specific residues within RNA polymerase sequence may prove valuable in devising strategies aimed at the control of rotavirus replication and infection.

Amino Acid Sequence↗

PubMed1992

Neutralizing epitopes on herpes simplex virus-1-expressed rotavirus VP7 are dependent on coexpression of other rotavirus proteins.

We constructed a recombinant thymidine kinase-negative herpes simplex virus type 1 (HSV-1) that expressed the rotavirus major outer capsid glycoprotein, VP7. In the recombinant HSV-1, a promoter from the 5' noncoding region of the HSV-1 glycoprotein B locus regulated the expression of VP7 as a HSV-1 gamma 1 gene product. HSV-1-expressed VP7 resembled rotavirus-expressed VP7 in its SDS-PAGE mobility, high mannose-type glycosylation, disulfide bonding, perinuclear to cytoplasmic localization, intracellular retention, and reactivity with polyclonal antisera and nonneutralizing antibodies. Unlike rotavirus-expressed VP7, HSV-1-expressed VP7 lacked several neutralizing epitopes by immuno-histochemical staining and by ELISA. One neutralizing epitope identified on HSV-1-expressed VP7 by ELISA was masked by paraformaldehyde fixation of recombinant HSV-1- but not rotavirus-infected cells. Neutralizing epitopes were restored to HSV-1-expressed VP7 by coinfection of cells with the HSV-1 recombinant and a heterologous rotavirus that lack the neutralizing epitopes. The recovered neutralizing epitopes were detected on double-shelled rotavirus particles produced in the coinfected cells. This study indicates that the formation of several neutralizing epitopes on rotavirus VP7 requires interaction of VP7 with other rotavirus proteins. In addition, HSV-1 was a useful vector for studying the localization, processing, and antigenicity of an RNA virus glycoprotein.

Animals↗

PubMed1994

Studies on the survival of aerosolized bovine rotavirus (UK) and a murine rotavirus.

The effect of relative humidity (RH) and temperature on the survival of airborne bovine rotavirus UK isolate (BRV-UK) and a murine rotavirus (MRV) was studied. In any one experiment, the virus under test was suspended in tryptose phosphate broth (TPB) supplemented with uranine (physical tracer) and an antifoam, was aerosolized using a Collison nebulizer into the rotating drum with the RH at either low (30 +/- 5%), medium (50 + 5%) or high (80 +/- 5%) level at 20 +/- 1 degrees C. Following a 15-min period of viral aerosol stabilization, sequential samples of drum air were collected using an All-Glass Impinger (AGI) for 24 h post-aerosolization. Both of the rotavirus isolates were found to survive best at medium RH level and high RH was found least favorable for the survival of these aerosolized rotaviruses. The survival pattern of aerosolized MRV was found to be the best when compared with survival pattern of all animal and human rotavirus isolates studies performed under aerosolized conditions in our laboratory. The findings of these experiments confirm and extend our previous reports on the survival of other animal and human aerosolized rotaviruses and emphasize the fact that air may be one of the vehicles for their dissemination and could explain why it is difficult to control nosocomial outbreaks of rotavirus gastroenteritis and to keep animal colonies rotavirus-free.

Air Microbiology↗