Thermophilic Campylobacter spp. in Danish broiler production: a cross-sectional survey and a retrospective analysis of risk factors for occurrence in broiler flocks.

In order to elucidate the rate of thermophilic Campylobacter spp. carriage in Danish broiler production and to identify risk factors for occurrence of campylobacter in broiler flocks, a total of 88 randomly selected broiler flocks were tested for campylobacter infection, and a subsequent study of risk factors based on a questionnaire was conducted. The sample material comprised cloacal swabs from live birds before slaughter, and neck skin samples from carcasses at the end of the processing line. A total of 52% of the flocks were found Campylobacter spp.-positive before slaughter. At the end of processing, 24% of the flocks were positive. The species distribution was 87% Campylobacter jejuni, 8% Campylobacter coli and 5% Campylobacter lari. The following parameters were identified as significant risk factors: lack of a hygiene barrier (odds ratio (OR) = 3.1, 1.1 < OR < 9.3), presence of animals in the vicinity of the broiler house on farms with a missing hygiene barrier (OR = 7.0, 1.6 < OR < 33.9), livestock other than chickens on farms with a missing hygiene barrier (OR = 7.6, 1.4 < OR < 44.9), dividing the flock into batches for staggered slaughter (OR = 6.8, 1.2 < OR < 49.3), a down period of less than 14 days (OR = 5.0, 1.2 < OR < 22.6), and feeding purchased wheat rather than home-grown wheat (OR = 3.1, 1.0 <OR < 9.9). The presence of a hygiene barrier was found to be the single most important biosecurity measure for production of campylobacter-free broilers.