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

• Published in: Journal of dairy science 2012-03, Vol.95 (3), p.1162-1165
• Main Authors: Slana, I., Kralik, P., Kralova, A., Babak, V., Pavlik, I.
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; Cattle; Cattle Diseases - diagnosis; Cattle Diseases - microbiology; cows; dairy herds; DNA; DNA, Bacterial - genetics; farms; feces; Female; filters; Filtration - veterinary; Food industries; food safety; Fundamental and applied biological sciences. Psychology; milk; Milk - microbiology; milk analysis; Milk and cheese industries. Ice creams; milk product; Mycobacterium avium subsp. paratuberculosis; Mycobacterium avium subsp. paratuberculosis - genetics; paratuberculosis; Paratuberculosis - diagnosis; pathogens; PCR; probability; quantitative polymerase chain reaction; Real-Time Polymerase Chain Reaction - methods; Real-Time Polymerase Chain Reaction - veterinary; statistical analysis; Terrestrial animal productions; tissue culture; Vertebrates
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2011-4658

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.