Presence of Campylobacter on Dutch broiler farms and associated risk factors

Campylobacter remains the most common reported zoonotic pathogen in humans in the European Union since 2008 (EFSA, 2018). Poultry is a major source of human infection with Campylobacter, although the epidemiology of Campylobacter at broiler farms is still poorly understood. The purpose of the study was to investigate factors associated with the presence of Campylobacter on a selected number of broiler farms in the Netherlands. The investigations were conducted starting from spring/summer 2017 until autumn 2018. Faecal samples were collected on a weekly basis at 21 farms, from one, two or three houses. There were 38 houses participating in the study. Information on flock and farm characteristics including biosecurity measures was gathered via a questionnaire (CAMPAS) and food chain information forms (VKI forms). In addition activities (other than routine activities) at the farms were described by the farmers in log books. The collected data were used as putative variables for a risk factors analysis. In total 284 flocks were sampled of which 32% were positive for Campylobacter. A multivariate logistic regression model revealed three factors associated with presence of Campylobacter in broiler flocks. They included summer/autumn season, mowing premises in the surroundings of the farm and the previous Campylobacter positive flock in the house. Although the factor breed did not remain in the final model, there was a difference in the time of becoming infected between regular and slow growing breeds. With the available data set the thinning practice was not confirmed as a risk factor. Evaluation of the outcome of the biosecurity questionnaire (CAMPAS) revealed an association between both poor hygienic practices on farm as well as the number of houses on farms with Campylobacter presence. Some indicators addressed in the questionnaire however need adjustment to be used as a predictive tool for introduction of Campylobacter on broiler farms. More studies are needed to furt