Association of enteric shedding of bovine torovirus (Breda virus) and other enteropathogens with diarrhea in veal calves.
OBJECTIVE
To determine the prevalence, fecal shedding pattern, and association of bovine torovirus (BoTV) with diarrhea in veal calves at time of arrival and periodically throughout the first 35 days after their arrival on a veal farm.


METHODS
62 veal calves.


METHODS
Fecal samples collected on days 0, 4, 14, and 35 after arrival were tested for BoTV by use of ELISA and reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Paired serum samples obtained from blood collected on days 0 and 35 were analyzed for BoTV antibodies with a hemagglutination inhibition assay. Fecal samples were also screened for other enteric pathogens, including rotavirus, coronavirus, and Cryptosporidium spp.


RESULTS
Fecal shedding of BoTV was detected in 15 of 62 (24%) calves by use of ELISA and RT-PCR assay, with peak shedding on day 4. A significant independent association between BoTV shedding and diarrhea was observed. In addition, calves shedding > or = 2 enteric pathogens were more likely to have diarrhea than calves shedding < or = 1 pathogen. Calves that were seronegative or had low antibody titers against BoTV (< or = 1:10 hemagglutination inhibition units) at arrival seroconverted to BoTV (> 4-fold increase in titer); these calves were more likely to shed virus than calves that were seropositive against BoTV at arrival.


CONCLUSIONS
Shedding of BoTV was strongly associated with diarrhea in neonatal veal calves during the first week after arrival at the farm. These data provide evidence that BoTV is an important pathogen of neonatal veal calves.
Hoet
Armando E
AE
Departamento de Enfermedades Transmisibles, Cátedra de Enfermedades Infecciosas, Facultad de Ciencias Veterinarias, La Universidad del Zulia, Maracaibo, Venezuela.
Smiley
Jeffrey
J
Thomas
Christopher
C
Nielsen
Paul R
PR
Wittum
Thomas E
TE
Saif
Linda J
LJ
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis / Q000821:virology*; D003126:Colostrum / Q000276:immunology; D018352:Coronavirus Infections / Q000150:complications / Q000175:diagnosis / Q000662:veterinary / Q000821:virology; D017938:Coronavirus, Bovine / Q000302:isolation & purification; D003967:Diarrhea / Q000150:complications / Q000662:veterinary* / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000821:virology; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D015995:Prevalence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012401:Rotavirus / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000150:complications / Q000175:diagnosis / Q000662:veterinary / Q000821:virology; D017003:Torovirus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000502:physiology*; D018176:Torovirus Infections / Q000150:complications / Q000175:diagnosis / Q000662:veterinary* / Q000821:virology; D014776:Virus Cultivation; D017201:Virus Shedding
D000914:Antibodies, Viral; D007074:Immunoglobulin G