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


METHODS
57 steers.


METHODS
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
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.
Hoet
Armando E
AE
Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA.
Cho
Kyoung-Oh
KO
Chang
Kyeong-Ok
KO
Loerch
Steven C
SC
Wittum
Thomas E
TE
Saif
Linda J
LJ
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology*; D005243:Feces / Q000821:virology; D006386:Hemagglutination Tests; D008137:Longitudinal Studies; D008297:Male; D009296:Nasal Cavity / Q000821:virology; D011446:Prospective Studies; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016036:Seroepidemiologic Studies; D017003:Torovirus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018176:Torovirus Infections / Q000175:diagnosis / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D017201:Virus Shedding; D014903:West Virginia / Q000453:epidemiology
D000914:Antibodies, Viral; D012367:RNA, Viral