Proceedings of the 10th International Colloquium on Paratuberculosis

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Control <strong>of</strong> paratuberculosis by vaccination - a systematic review and meta-analysis
Heike Köhler, Franziska Gierke, Tassilo Seidler, Mario Ziller
Institute <strong>of</strong> Molecular Pathogenesis, Friedrich-Loeffler-Institut, Jena, Germany; Institute <strong>of</strong> Epidemiology, Friedrich-
Loeffler-Institut, Wusterhausen, Germany
Objective: The effects <strong>of</strong> vaccination against paratuberculosis and its significance in <strong>the</strong> control <strong>of</strong> <strong>the</strong> disease
were examined.
Materials and Methods: After thorough literature searches, vaccination studies in domestic ruminants
published between 1961 and 2009 were selected by predefined criteria. Publications were separated in
experimental (n=12) and field studies (n=14). Important criteria for <strong>the</strong> selection were direct verification <strong>of</strong>
disease (pathological/histological examination, organ culture, fecal culture) and comparison <strong>of</strong> results for
vaccinated and non-vaccinated groups. In experimental studies, all animals were infected orally with MAP
after vaccination <strong>of</strong> one group. In field studies, young animals in infected herds were vaccinated, <strong>the</strong> infection
status <strong>of</strong> <strong>the</strong> individual animal was unknown at <strong>the</strong> time <strong>of</strong> vaccination. Odds ratios (OR) were calculated to
estimate <strong>the</strong> effects <strong>of</strong> vaccination on pathological/histological, organ culture and fecal culture results. In metaanalyses,
results <strong>of</strong> primary analyses were integrated. Studies summarized in each meta-analysis were tested
for homogeneity (Cochran´s Q-Test, I²-statistic) and fixed or random effect models were chosen to estimate <strong>the</strong>
pooled OR as an indicator <strong>of</strong> effect size.
Results: In experimental studies <strong>the</strong> chance for a positive pathological/histological result (OR=0.3535)
or a positive organ culture result (OR=0.3496) was significantly reduced in animals vaccinated prior infection.
In field studies, significantly decreased MAP detection rates were recorded in vaccinated animals regarding
pathological/histological lesions (OR=0.1726), organ culture (OR=0.3992) and fecal culture (OR=0.2369).
Conclusions: No general protection against paratuberculosis infection can be achieved by vaccination.
It is impossible to prevent infection in dairy cattle only by implementation <strong>of</strong> vaccination programs. Reduction
<strong>of</strong> pathological findings and decrease <strong>of</strong> positive culture results indicate a lower risk <strong>of</strong> infection for vaccinated
animals. The decrease <strong>of</strong> positive fecal culture results after vaccination can possibly reduce <strong>the</strong> environmental
load in infected herds.
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