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; however, group B rotavirus infections of foals emerged in 2021. 9 , 10 Within each group, 11 gene segments code for 6 structural and 5 nonstructural proteins that comprise the nonenveloped virus particles. 2 , 11 Six structural proteins designated as VP1

Open access
in American Journal of Veterinary Research

Summary

Macromolecular permeability of the small intestine was tested in four 3-week-old gnotobiotic pigs inoculated with porcine rotavirus strain RV277 (group A). Pigs were administered 126I-labeled polyvinylpyrrolidone (molecular weight [mol wt], 40,000) orally 1 day before and 2 and 24 hours after virus inoculation, and blood samples were obtained every 6 hours. Eight hours after rotavirus inoculation, pigs had watery diarrhea. Increased permeation of 125I-labeled polyvinylpyrrolidone was not observed after clinical signs of infection had developed. Serum total protein and urea nitrogen concentrations increased slightly at the end of the study, probably as a consequence of dehydration. Differences in blood glucose concentration were not seen. At 48 hours after viral inoculation, macromolecular permeability was tested morphologically by injecting horseradish peroxidase (mol wt, 40,000) into the jejunal lumen just distally to the ligamentum colicoduo-denale. After am incubation period of 20 minutes, small segments of jejunum were obtained for stereomicroscopic, histologic, and ultrastructural investigations. Moderate hyperregenerative villus atrophy was found. Ultrastructural changes of the villus epithelium were minor, and increased macromolecular permeation was not observed.

Free access
in American Journal of Veterinary Research

Summary

The infectivity and pathogenic potential of a cell culture-adapted simian rotavirus was evaluated in colostrum-deprived newborn and infant cynomolgus macaques (Macaca fascicularis). Intragastric challenge exposure with the simian rotavirus strain SA11 on postpartum day 2 induced diarrhea in 5 of 5 colostrum-deprived newborn monkeys. Compared with sham-inoculated controls, 3 of the 5 inoculated monkeys also manifested reduced body weight gain during the initial 5 days after challenge exposure. Rotavirus was detected in feces of 3 challenge-exposed monkeys for up to 2 days after inoculation. Evaluation of antibody response after rotavirus inoculation was obscured by high but variable prechallenge-exposure serum titers of rotavirus-specific antibody. Preexisting serum titer of neutralizing antibody in newborn monkeys was not predictive of clinical response to inoculation with rotavirus SA11. Two 90-day-old infant monkeys with low serum neutralizing antibody titer did not have diarrhea, reduced weight gain, or antibody response after oral inoculation with rotavirus SA11. Results of these challenge-exposure studies in newborn cynomolgus monkeys were consistent with a heterologous host-rotavirus model and indicate that neonatal serum antibody of maternal origin may not be associated with resistance to rotavirus-induced disease.

Free access
in American Journal of Veterinary Research

Summary

Fecal samples were collected from 450 neonatal calves ranging from 1 to 30 days old, between May, 1988 and May, 1989 to estimate the prevalence of bovine group A rotavirus in a stratified random sample of Ohio daily herds. Calves were from 47 dairy herds chosen to be representative of Ohio herds. Bovine group A rotavirus was detected in fecal samples by a cell culture immunofluorescence test (ccif) and elisa. Of 450 samples tested, 46 (10%) were positive by ccif and 67 (15%) were positive by elisa. The agreement beyond chance between the 2 assays was good (kappa = 0.65). The overall prevalence rate of rotavirus shedding was 16.4% (74/450). Forty-three percent (29/67) of the samples positive by elisa were subgroup 1, none were subgroup 2, and the remaining 57% (38/67) could not be assigned to either subgroups 1 or 2. Thirty herds (62.5%) had at least 1 group A rotavirus-positive calf (mean number of samples per positive herd = 12.4), and 17 herds (37.5%) had no rotavirus-positive calves (mean number of samples per negative herd = 6.0). A live oral rotacoronavirus vaccine was used in neonatal calves of only 1 herd and 3 of 17 (17.6%) calves from this herd were positive for group A rotavirus. The percentage of the rotavirus-positive fecal samples from all calves (n = 450) when stratified by fecal consistency was as follows: 28.3% (13/46) had liquid feces; 25.6% (10/39) had semiliquid feces; 23.4% (22/94) had pasty feces; and 10.7% (29/271) had firm feces. Of the rotavirus-positive calves (n = 74), 17.6% (13/74) had liquid feces; 13.5% (10/74) had semiliquid feces; 29.7% (22/74) had pasty feces; and 39.2% (29/74) had firm feces. The average age of calves shedding rotavirus was 14 days (range, 1 to 30 days). Double-stranded (ds) rna extracted from 36 samples positive by 1 or both tests was examined by polyacrylamide gel electrophoresis. All samples positive by this technique (30/36) had long dsrna migration patterns, typical of group A rotaviruses, including samples from calves in the herd in which the oral vaccine was used. Moreover, the electrophoretic migration pattern of group A rotavirus dsrna in these vaccinated calves differed from that of the rotavirus vaccine strain, suggesting the rotavirus strain circulating in this herd was not the vaccine strain. All samples negative by ccif or elisa that had volumes > 5 ml (n = 323) were also subjected to dsrna extraction and polyacrylamide gel electrophoresis for detection of additional group A or nongroup A rotaviruses; none of them were positive by this technique.

Free access
in American Journal of Veterinary Research

Objective—

To determine safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine.

Design—

Prospective randomized controlled trial.

Animals—

316 pregnant Thoroughbred mares during the first year of the study and 311 during the second year.

Procedure—

During the first year, mares received 3 doses of vaccine or placebo, IM, at 8, 9, and 10 months of gestation. Serum neutralizing antibody titers were measured before vaccination and 1 and 35 days after foaling. Antibody titers were measured in foals 1, 7, 35, 60, 90, and 120 days after birth. During the second year, mares that had been vaccinated the previous year received a single booster dose of vaccine approximately 1 month prior to parturition. Mares that had received the placebo the previous year and mares new to the study received 3 doses of vaccine or placebo. Serum neutralizing antibody titers were measured in samples taken from mares approximately 1 day after foaling and from foals approximately 1 and 60 days after birth.

Results—

Adverse reactions were not observed. Antibody titers were significantly increased at the time of foaling and 35 days after foaling in vaccinated, compared with control, mares and for 90 days after birth in foals born to vaccinated, compared with foals born to control, mares. Incidence of rotaviral diarrhea was lower in foals born to vaccinated, compared with foals born to control, mares, but the difference was not significant.

Clinical Implications—

Results suggest that the equine rotavirus vaccine is safe and immunogenic and that reasonable efficacy under field conditions can be expected. (J Am Vet Med Assoc 1997;211:193–198)

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

A virologic survey was conducted on calves with diarrhea associated with bovine rotavirus (brv) on a closed dairy farm. The brv was detected from 32 of 219 (14.6%) fecal specimens repeatedly collected from 56 calves born during the years 1992-1993, regardless of whether they had diarrhea. Most of the 32 strains were isolated from fecal specimens obtained from 2- to 6-week-old calves. After electrophoresis of double-stranded viral rna from the 32 strains, genomic rna migration patterns were similar to those of the predominant brv strains isolated at the same farm during the years 1990-1991. All representative strains were identified as G serotype 6 (G6) and P type 5 (P5) by results of the virus-neutralization test and polymerase chain reaction procedure. Thus, brv had no change in genomic rna electropherotypes and serologic antigenicities in a closed dairy herd over a period of several years.

Free access
in American Journal of Veterinary Research

Summary

A rapid elisa was developed for simultaneous detection of bovine coronavirus (bcv), rotavirus (rv) serogroup A, and Escherichia coli K99 antigen in feces of calves. A mixture of 3 monoclonal antibodies specific for bcv, rv, or K99 was used successfully to capture the antigens; the same antibodies labeled with peroxidase were used to detect bcv, rv, or K99. The triple elisa was compared with standard reference diagnostic methods by examining feces from experimentally and naturally infected and healthy calves. All the components of the test were highly specific (> 90%) and sensitive (bcv, 77%; K99, 93%; rv, 100%) when used in a format requiring short incubation steps at 20 C and visual recording of results.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To compare experimentally induced concurrent infection with bovine viral diarrhea virus (BVDV) and bovine rotavirus (BRV) with infection of either virus alone in calves.

Animals—Seventeen 1-day-old gnotobiotic calves.

Procedure—Calves were allotted to 8 treatments as follows: group 1, mock-infected control calves (n = 2); group 2, inoculated with BVDV on day 1 (2); groups 3, 5, and 7, inoculated with BRV on days 1 (2), 4 (1), or 7 (2), respectively; and groups 4, 6, and 8, inoculated with BVDV on day 1 and with BRV on days 1 (2), 4 (2), or 7 (4), respectively. Concentrations of BVDV in serum and ileal tissues were measured, and BRV shedding in feces was determined. Histologic examination and immunohistochemical analysis were conducted to detect lesions and viral antigens.

Results—Neonatal calves inoculated with BVDV alone or with BVDV on day 1 and BRV on day 7 developed villus atrophy and submucosal inflammation of the intestines. Concurrent BVDV and BRV infections acted synergistically in the intestinal tract, causing more severe enteric disease than infection with either virus alone. Severe lymphoid depletion was associated with BVDV infection in calves regardlesss of concurrent BRV infection.

Conclusions and Clinical Relevance—Infection with BVDV played direct and indirect roles in enteritis in neonatal calves, causing villus atrophy in the duodenum and submucosal inflammation of the intestines. Also, BVDV potentiated effects of BRV. Concurrent infection with BVDV and BRV resulted in more severe enteric disease in neonatal calves than infection with BRV or BVDV alone. (Am J Vet Res 2002;63:1179–1186)

Full access
in American Journal of Veterinary Research

rotavirus, were detected in dogs both with and without diarrhea ( Table 3 ). Of individual enteropathogens identified, only CPEA was significantly ( P = 0.02) more common in dogs with diarrhea than in dogs with normal feces. Canine coronavirus was

Full access
in Journal of the American Veterinary Medical Association