title: Nested PCR on blood and milk for the detection of Mycobacterium avium subsp paratuberculosis DNA in clinical and subclinical bovine paratuberculosis.
abstract: OBJECTIVE
  To determine the potential of PCR on blood and milk to detect cattle infected with Mycobacterium avium subsp paratuberculosis.
  
  
  METHODS
  A nested PCR method probing for IS900 was developed and compared to ELISA serology in 11 clinically infected and 46 subclinically infected, lactating Holstein cows from a herd with confirmed paratuberculosis (Johne's disease).
  
  
  RESULTS
  When compared to serum ELISA the nested blood- and milk PCRs were equal in identifying DNA from clinically infected animals. The PCR procedures also gave positive DNA results with some subclinically infected animals when these only gave suspicious or negative results in the ELISA test. Most clinically and subclinically infected animals were detected with milk PCR.
  
  
  CONCLUSIONS
  Since there may well be a haematological phase in paratuberculosis, nested PCR testing of blood and milk samples shows potential to detect animals subclinically infected with M a paratuberculosis. More subclinically infected animals need to be tested and confirmed infected before estimates of sensitivity and specificity can be made.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, University of Florida, PO Box 110880, Gainesville, Florida 32610, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Buergelt
authors.forename: J E
authors.initials: JE
authors.lastname: Williams
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology; D004269:DNA, Bacterial / Q000032:analysis; D003612:Dairying; D004586:Electrophoresis / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D005431:Florida / Q000453:epidemiology; D008892:Milk / Q000382:microbiology; D009000:Monocytes / Q000276:immunology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011237:Predictive Value of Tests
chemical_list: D004269:DNA, Bacterial