Prävalenz von Paratuberkulose in Schweizer Milchviehbeständen und Risikofaktoren für einen positiven Herdenstatus

• Forschungsstelle: BLV
• Projektnummer: 1.21.05

Schlüsselwörter (Deutsch)

Paratuberkulose – Seroprävalenz – Herde – Milchindustrie – Zertifizierung

Schlüsselwörter (Englisch)

Paratuberculosis – seroprevalence – herd-  dairy industry – certification

Kurzbeschreibung (Deutsch)

Es sind keine Daten über die aktuelle Prävalenz der Paratuberkulose in Schweizer Milchviehbetrieben verfügbar. Mittels Serologie (schnelle, kostengünstige Diagnostikmethode mit bekannten Vor- und Nachteilen) wird anhand einer repräsentativen Stichprobe (berechnet als 300 Herden mit 42 Tieren im Durchschnitt) die Herdenprävalenz von Paratuberkulose in Schweizer Milchviehbetrieben sowie die Tierprävalenz innerhalb infizierter Herden bestimmt. Anhand von Fragebögen werden weiter Daten über das Management in den beprobten Betrieben erfasst, um mittels Risikofaktorenanalyse die wichtigsten Parameter zu identifizieren, welche mit einem positiven Status und/oder einer hohen Prävalenz im Betrieb assoziiert sind. Bei bedeutender Paratuberkulose-Prävalenz in Milchviehbetrieben müssen dann die effizientesten Diagnostikmethoden und -strategien für die spezifischen Produktionsbedingungen der Schweiz evaluiert werden, um die wissenschaftliche Grundlage zur Diskussion von möglichen Kontrollstrategien, z.B. freiwilligen Zertifizierungsprogrammen, mit der Milchbranche zu schaffen.

Kurzbeschreibung (Englisch)

Data on the prevalence of paratuberculosis in Swiss dairy herds are currently not available. The herd prevalence in Swiss dairy operations as well as the within-herd prevalence in infected herds will be determined by use of serology (as a rapid, cost-efficient diagnostic method with well-defined advantages and limitations) based on a representative subset of the Swiss dairy population (calculated sample size based on previous studies = 300 herds with an average of 42 animals). Information regarding management practices in participating herds will be gathered by use of questionnaires to identify the main risk factors associated with positive herd status and high within-herd prevalence. If a relevant paratuberculosis prevalence is observed in Swiss dairies, the most efficient diagnostic methods and strategies will need to be evaluated under the specific conditions of milk production in Switzerland to provide a scientific basis for the discussion of possible control strategies, e.g. voluntary certification programs, with milk producers and retailers in Switzerland.

Projektziele (Englisch)

The objectives of the project include:

 i) the determination of the between-herd prevalence of paratuberculosis in Swiss dairy herds based on a well-established serological method (ELISA), so that the estimation of the true prevalence will be possible based on the test results and characteristics,

ii) the determination of the within-herd prevalence of paratuberculosis in infected dairy herds, which is complementary to the between-herd prevalence in order to assess the countrywide relevance of the disease,  

iii) the identification of risk factors associated with a positive herd status and a high within-herd prevalence regarding paratuberculosis in a representative sample of Swiss dairy farms, in order to identify management factors associated with introduction and spread of MAP in infected herds.

 

This grant application (project abstract, Projektskizze) was submitted (in March 2020) jointly with another research project aimed at taking the next logical step in addressing paratuberculosis in Swiss dairy herds, i.e. the development of recommendations for the design of control strategies based on the results of objectives i) to iii) above. The objective of this second project was to evaluate the suitability of several rapid and affordable diagnostic methods to determine the infection status of Swiss dairy herds (infected vs. free of paratuberculosis). The results from analyses of different matrices (serum, milk, environmental samples), sampling strategies (e.g. individual milk samples vs. repeated bulk tank milk samples, whole herd serology vs. subset of animals with the highest risk) and methods (ELISA, PCR), and combinations thereof should be explored to define the accuracy of different strategies for determination of the infection status of dairy herds. The most adequate strategy may then be used for certification programs in Swiss dairy herds.

Although the FSVO decided last spring to pursue the seroprevalence study only in a first step, a detailed description of synergies between the two projects was requested (Auflage gemäss BLV-Antwortschreiben vom 8.5.2020) with the full project description of the seroprevalence study. These synergies and the consequences of not taking advantage therof for the realization of the seroprevalence project and for the evaluation of diagnostic strategies are depicted below in 6.4. (Methods) and 6.5. (Time schedule).

Publikationen / Ergebnisse (Deutsch)

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