Within-herd prevalence thresholds for the detection of Mycobacterium avium subspecies paratuberculosis-positive dairy herds using boot swabs and liquid manure samples

Abstract

The control of Johne's disease requires the identification of Mycobacterium avium ssp. paratuberculosis (MAP)-positive herds. Boot swabs and liquid manure samples have been suggested as an easy-to-use alternative to sampling individual animals in order to diagnose subclinical Johne's disease at the herd level, but there is a need to evaluate performance of this approach in the field. Using a logistic regression model, this study aimed to calculate the threshold level of the apparent within-herd prevalence as determined by individual faecal culture, thus allowing the detection of whether a herd is MAP positive. A total of 77 boot swabs and 75 liquid manure samples were taken from 19 certified negative and 58 positive dairy herds. Faecal culture, three different polymerase chain reaction (PCR) methods and the combination of faecal culture with PCR were applied in order to detect MAP. For 50% probability of detection, a within-herd prevalence threshold of 1·5% was calculated for testing both matrices simultaneously by faecal culture and PCR, with the threshold increased to 4·0% for 90% probability of detection. The results encourage the use of boot swabs or liquid manure samples, or a combination both, for identifying MAP-positive herds and, to a certain extent, for monitoring certified Johne's disease-negative cattle herds.

Evaluation of different diagnostic methods for the detection of Mycobacterium avium subsp. paratuberculosis in boot swabs and liquid manure samples

“…Additionally, samples from LM storage areas (tanks, lagoons, pits or pre-flooders) were obtained as described recently by Donat et al [ 7 ].…”

“…paratuberculosis (MAP) in dairy herds, an approach overcoming the issue of sampling location and further reducing effort and cost [ 6 ]. The detection limit of this approach in terms of within-herd prevalence (WHP) is low [ 7 ], but depends on the laboratory methods used to substantiate MAP in the samples. Faecal culture (FC), still considered the most sensitive method for MAP detection is time-consuming and prone to microbial contamination [ 8 ].…”

Development of a hierarchical typing approach for Mycobacterium avium subsp. paratuberculosis (MAP) and characterization of MAP field cultures from Central Germany

“…Field cultures were obtained from the mycobacteria collections of the Hessian State Laboratory, Giessen, Germany. They were collected in the course of voluntary MAP surveillance programmes in three German federal states (Hesse, Thuringia and Saxony; Eisenberg et al 2013;Donat et al 2016;Hahn et al 2017). The respective cultures were primarily cultivated on Herrold's egg yolk medium (HEYM) agar slants supplemented with mycobactin J (MJ; HEYM-MJ; BD, Heidelberg, Germany) using faecal or environmental samples originating from dairy herds (n = 81), where growth was observed within 6-8 weeks.…”

Zweistufige Paratuberkulosebekämpfung in der Praxis: Überwachung auf Herdenebene als Basis für betriebliche Maßnahmen zur Prävalenzsenkung

“…Die Eignung von Sockentupfern zur Bestimmung des MAP-Bestandsstatus wurde in zahlreichen Studien belegt [22] [24][25] [26] und die Sensitivität in Abhängigkeit von der Intraherdenprävalenz der MAP-Ausscheider für eine einmalige Untersuchung beschrieben [27]. Inwieweit die Sensitivität dieses Ansatzes durch wiederholte Untersuchungen in regelmäßigen zeitlichen Abständen erhöht werden kann, bedarf weiterer Untersuchungen.…”