title: Comparison of fecal culture and F57 real-time polymerase chain reaction for the detection of Mycobacterium avium subspecies paratuberculosis in Swiss cattle herds with a history of paratuberculosis.
abstract: BACKGROUND
  Bovine paratuberculosis is an incurable chronic granulomatous enteritis caused by Mycobacterium avium subspecies paratuberculosis (MAP). The prevalence of MAP in the Swiss cattle population is hard to estimate, since only a few cases of clinical paratuberculosis are reported to the Swiss Federal Food Safety and Veterinary Office each year.Fecal samples from 1,339 cattle (855 animals from 12 dairy herds, 484 animals from 11 suckling cow herds, all herds with a history of sporadic paratuberculosis) were investigated by culture and real-time polymerase chain reaction (PCR) for shedding of MAP.
  
  
  RESULTS
  By culture, MAP was detected in 62 of 445 fecal pools (13.9%), whereas PCR detected MAP in 9 of 445 pools (2.0%). All 186 samples of the 62 culture-positive pools were reanalyzed individually. By culture, MAP was grown from 59 individual samples (31.7%), whereas PCR detected MAP in 12 individual samples (6.5%), all of which came from animals showing symptoms of paratuberculosis during the study. Overall, MAP was detected in 10 out of 12 dairy herds (83.3%) and in 8 out of 11 suckling cow herds (72.7%).
  
  
  CONCLUSIONS
  There is a serious clinically inapparent MAP reservoir in the Swiss cattle population. PCR cannot replace culture to identify individual MAP shedders but is suitable to identify MAP-infected herds, given that the amount of MAP shed in feces is increasing in diseased animals or in animals in the phase of transition to clinical disease.
authors.forename: Selina M
authors.initials: SM
authors.lastname: Keller
authors.forename: Roger
authors.initials: R
authors.lastname: Stephan
authors.forename: Rahel
authors.initials: R
authors.lastname: Kuenzler
authors.forename: Mireille
authors.initials: M
authors.lastname: Meylan
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 270, Zurich, CH-8057, Switzerland. wittenbr@vetbakt.uzh.ch.
authors.forename: Max M
authors.initials: MM
authors.lastname: Wittenbrink
mesh_terms: D000818:Animals; D058491:Bacterial Load / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D005260:Female; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary*; D013557:Switzerland / Q000453:epidemiology