Detection and characterization of viruses as field and vaccine strains in feedlot cattle with bovine respiratory disease.
This study investigated viruses in bovine respiratory disease (BRD) cases in feedlots, including bovine herpesvirus-1 (BoHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine coronaviruses (BoCV) and parainfluenza-3 virus (PI3V). Nasal swabs were collected from 114 cattle on initial BRD treatment. Processing included modified live virus (MLV) vaccination. Seven BRD necropsy cases were included for 121 total cases. Mean number of days on feed before first sample was 14.9 days. Swabs and tissue homogenates were tested by gel based PCR (G-PCR), quantitative-PCR (qPCR) and quantitative real time reverse transcriptase PCR (qRT-PCR) and viral culture. There were 87/114 (76.3%) swabs positive for at least one virus by at least one test. All necropsy cases were positive for at least one virus. Of 121 cases, positives included 18/121 (14.9%) BoHV-1; 19/121 (15.7%) BVDV; 76/121 (62.8%) BoCV; 11/121 (9.1%) BRSV; and 10/121 (8.3%) PI3V. For nasal swabs, G-PCR (5 viruses) detected 44/114 (38.6%); q-PCR and qRT-PCR (4 viruses) detected 81/114 (71.6%); and virus isolation detected 40/114 (35.1%). Most were positive for only one or two tests, but not all three tests. Necropsy cases had positives: 5/7 G-PCR, 5/7 q-PCR and qRT-PCR, and all were positive by cell culture. In some cases, G-PCR and both real time PCR were negative for BoHV-1, BVDV, and PI3V in samples positive by culture. PCR did not differentiate field from vaccines strains of BoHV-1, BVDV, and PI3V. However based on sequencing and analysis, field and vaccine strains of culture positive BoHV-1, BoCV, BVDV, and PI3V, 11/18 (61.1%) of BoHV-1 isolates, 6/17 (35.3%) BVDV isolates, and 1/10 (10.0%) PI3V identified as vaccine. BRSV was only identified by PCR testing. Interpretation of laboratory tests is appropriate as molecular based tests and virus isolation cannot separate field from vaccine strains. Additional testing using sequencing appears appropriate for identifying vaccine strains.
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA. Electronic address: Robert.fulton@okstate.edu.
R W
RW
Fulton
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA.
J M
JM
d'Offay
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA.
C
C
Landis
Veterinary Research and Consulting Services, Greeley, CO 80634, USA.
D G
DG
Miles
Veterinary Research and Consulting Services, Stillwater, OK 74075, USA.
R A
RA
Smith
Athens Veterinary Diagnostic Laboratory, University of Georgia, Athens, GA 30602, USA.
J T
JT
Saliki
U.S. Department of Agriculture, Agricultural Research Service, National Animal Diseases Center, Ames, IA 50010, USA.
J F
JF
Ridpath
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA.
A W
AW
Confer
U.S. Department of Agriculture, Agricultural Research Service, National Animal Diseases Center, Ames, IA 50010, USA.
J D
JD
Neill
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA.
R
R
Eberle
Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA.
T J
TJ
Clement
Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA.
C C L
CC
Chase
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA.
L J
LJ
Burge
Department of Statistics, Oklahoma State University, Stillwater, OK 74078, USA.
M E
ME
Payton
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000821:virology*; D017938:Coronavirus, Bovine / Q000302:isolation & purification; D030241:Diarrhea Virus 1, Bovine Viral / Q000302:isolation & purification; D007242:Herpesvirus 1, Bovine / Q000302:isolation & purification; D009666:Nose / Q000821:virology; D029101:Parainfluenza Virus 3, Bovine / Q000302:isolation & purification; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D018112:Respiratory Syncytial Virus, Bovine / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000662:veterinary* / Q000821:virology; D014481:United States; D014613:Vaccines, Attenuated; D014765:Viral Vaccines
D014613:Vaccines, Attenuated; D014765:Viral Vaccines
Bovine respiratory viruses; Diagnostic virology; MLV vaccines