title: Use of a polymerase chain reaction assay to detect bovine leukosis virus in dairy cattle.
abstract: OBJECTIVE
  To evaluate the use of a polymerase chain reaction (PCR) assay in detecting bovine leukosis virus (BLV) in adult dairy cows.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  223 adult dairy cows.
  
  
  METHODS
  Cows were tested for BLV status by use of an ELISA and a PCR assay. Sensitivity, specificity, predictive values of positive and negative tests, and the percentage of cows correctly classified by PCR assay were calculated. Ninety-five percent confidence intervals were calculated for sensitivity and specificity.
  
  
  RESULTS
  Sensitivity and specificity were 0.672 and 1.00, respectively. Prevalence of BLV in this herd was 0.807. Predictive value of a positive test was 1.00, and predictive value of a negative test was 0.421. The percentage of cows correctly classified by PCR assay was 73.5%.
  
  
  CONCLUSIONS
  A positive PCR assay result provided definitive evidence that a cow was infected with BLV. Sensitivity and negative predictive value for PCR assay were low. Consequently, PCR assay alone is unreliable for routine detection of BLV in herds with high prevalence of the disease.
authors.affiliation: Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802, USA.
authors.forename: Dusty W
authors.initials: DW
authors.lastname: Nagy
authors.forename: Jeff W
authors.initials: JW
authors.lastname: Tyler
authors.forename: Steven B
authors.initials: SB
authors.lastname: Kleiboeker
authors.forename: Aaron
authors.initials: A
authors.lastname: Stoker
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002417:Cattle; D004279:DNA, Viral / Q000097:blood / Q000302:isolation & purification; D016583:Enzootic Bovine Leukosis / Q000175:diagnosis* / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D005260:Female; D001909:Leukemia Virus, Bovine / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral