Estimation of on-farm interventions to control Campylobacter

Before making risk management decisions to control Campylobacter prevalence in broiler flocks, it is useful to identify effective interventions. A given risk factor may seem to have a large effect, but in practice interventions related to this risk factor may have only limited effect due to a relative small proportion of the farms that can actually be intervened for the given risk factors.

We present a novel tool for risk assessors to obtain such estimates of the effect of interventions before it is implemented at the farms. A statistical method was developed in order to estimate the flock prevalence if an intervention was to be implemented in a given population of broiler farms. The method is anchored in the ideas behind standardized population estimations.

In order to obtain a country wise population estimate the predicted prevalence values are multiplied with elements from a reference population. In the present study risk factor estimates from a European study was used and the reference population consisted of data from the risk factor study plus extra data from a large questionnaire survey to improve the representativeness of the reference population.

The results showed that some individual interventions gave only a limited reduction in prevalence if the biosecurity was not accounted for. Furthermore, the effect of the interventions differed between countries, depending on current farm management practices and Campylobacter prevalence. The most effective interventions were “building new houses with strict biosecurity for all houses older than 15 years” and “apply drinkers with nipples without cups”.