title: Short communication: Examination of milk filters by real-time PCR as a herd-level indicator of the presence of Mycobacterium avium subspecies paratuberculosis in dairy herds.
abstract: The aim of this study was to assess the suitability of real-time quantitative PCR (qPCR) for the detection of Mycobacterium avium ssp. paratuberculosis (MAP) in milk filters as a herd level indicator of paratuberculosis infection. Seventy-nine samples from textile or metal milk filters from 15 herds with defined MAP prevalence (infection status = noninfected, 0-5%, 5-10%, or >10% of animals with clinically confirmed paratuberculosis) were analyzed. The MAP DNA was isolated by a modified commercially available protocol for feces, and detection and quantification of the pathogen was performed by the IS900 qPCR. Mycobacterium avium ssp. paratuberculosis DNA was detected in 63 (79.7%) samples. Determination of MAP infection established by fecal and tissue culture was correctly confirmed by the analysis of milk filters on 11 of 12 infected farms; MAP was not detected in filters from 3 farms where paratuberculosis was never diagnosed. Statistical analysis of the data supports the evidence that milk filters can be used as a template for the direct detection of MAP on the herd level. The probability of successful MAP detection in milk filters in a herd with MAP-infected cows is at least 94.3%. Absolute numbers of MAP detected on the milk filter can be used for a rough estimation of paratuberculosis prevalence >10% in the herd. Analysis of milk filters for the presence of MAP can be a useful tool for the detection of paratuberculosis on the herd level before any individual control strategies.
authors.affiliation: Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic. slana@vri.cz
authors.forename: I
authors.initials: I
authors.lastname: Slana
authors.forename: P
authors.initials: P
authors.lastname: Kralik
authors.forename: A
authors.initials: A
authors.lastname: Kralova
authors.forename: V
authors.initials: V
authors.lastname: Babak
authors.forename: I
authors.initials: I
authors.lastname: Pavlik
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005374:Filtration / Q000662:veterinary; D008892:Milk / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics; D010283:Paratuberculosis / Q000175:diagnosis*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*
chemical_list: D004269:DNA, Bacterial