Advertisement

Enteric and nasal shedding of bovine torovirus (Breda virus) in feedlot cattle

Armando E. HoetFood Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, OH 44691.
La Facultad de Ciencias Veterinarias, La Universidad del Zulia, Maracaibo, Venezuela.

Search for other papers by Armando E. Hoet in
Current site
Google Scholar
PubMed
Close
 DVM
,
Kyoung-Oh ChoFood Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, OH 44691.

Search for other papers by Kyoung-Oh Cho in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Kyeong-Ok ChangFood Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, OH 44691.

Search for other papers by Kyeong-Ok Chang in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Steven C. LoerchDepartment of Animal Sciences, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, OH 44691.

Search for other papers by Steven C. Loerch in
Current site
Google Scholar
PubMed
Close
 PhD
,
Thomas E. WittumDepartment of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210.

Search for other papers by Thomas E. Wittum in
Current site
Google Scholar
PubMed
Close
 PhD
, and
Linda J. SaifFood Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, OH 44691.

Search for other papers by Linda J. Saif in
Current site
Google Scholar
PubMed
Close
 PhD

Abstract

Objective—To assess fecal and nasal shedding patterns of bovine torovirus (BoTV) in cattle at time of arrival and periodically throughout the first 21 days after arrival at a feedlot.

Animals—57 steers.

Procedure—Fecal and nasal-swab samples collected on days 0, 4, 14, and 21 after arrival were tested for BoTV, using ELISA. A subset of samples from calves testing positive and negative for BoTV was analyzed, using reverse transcriptase-polymerase chain reaction (RT-PCR). Paired serum samples were collected on days 0 and 21 and tested for BoTV antibodies, using a hemagglutination inhibition assay.

Results—Overall rate of fecal shedding of BoTV was 21 of 57 (37%) by ELISA and 40 of 42 (95%) by RT-PCR with peak shedding on day 4. Diarrhea was more common in calves shedding BoTV than those not shedding the virus (odds ratio, 1.72). Overall rate of nasal shedding of BoTV was 15 of 57 (26%) by ELISA and 42 of 42 (100%) by RT-PCR, with peak shedding on day 0. Specificity of the RT-PCR product was confirmed by sequence analysis. Approximately 93% of the calves seroconverted to BoTV (> 4-fold increase in titer). Differences were not detected between calves shedding BoTV and nonshedders in relation to disease and treatments, perhaps because of the low number of cattle in the study.

Conclusions and Clinical Relevance—This study confirmed BoTV infections in feedlot cattle, including BoTV antigen and viral RNA in nasal secretions, and the shedding pattern during the first 21 days after arrival in a feedlot. (Am J Vet Res 2002;63:342–348).

Abstract

Objective—To assess fecal and nasal shedding patterns of bovine torovirus (BoTV) in cattle at time of arrival and periodically throughout the first 21 days after arrival at a feedlot.

Animals—57 steers.

Procedure—Fecal and nasal-swab samples collected on days 0, 4, 14, and 21 after arrival were tested for BoTV, using ELISA. A subset of samples from calves testing positive and negative for BoTV was analyzed, using reverse transcriptase-polymerase chain reaction (RT-PCR). Paired serum samples were collected on days 0 and 21 and tested for BoTV antibodies, using a hemagglutination inhibition assay.

Results—Overall rate of fecal shedding of BoTV was 21 of 57 (37%) by ELISA and 40 of 42 (95%) by RT-PCR with peak shedding on day 4. Diarrhea was more common in calves shedding BoTV than those not shedding the virus (odds ratio, 1.72). Overall rate of nasal shedding of BoTV was 15 of 57 (26%) by ELISA and 42 of 42 (100%) by RT-PCR, with peak shedding on day 0. Specificity of the RT-PCR product was confirmed by sequence analysis. Approximately 93% of the calves seroconverted to BoTV (> 4-fold increase in titer). Differences were not detected between calves shedding BoTV and nonshedders in relation to disease and treatments, perhaps because of the low number of cattle in the study.

Conclusions and Clinical Relevance—This study confirmed BoTV infections in feedlot cattle, including BoTV antigen and viral RNA in nasal secretions, and the shedding pattern during the first 21 days after arrival in a feedlot. (Am J Vet Res 2002;63:342–348).