Practical aspects of the suitability of different sampling methods for detecting Salmonella infection in duck flocks

While the consumption of duck eggs has gained popularity over the past few years, little is known about the prevalence of Salmonella in duck flocks and the associated potential Public Health impact. In order to detect Salmonella infection in duck flocks, sensitive sampling methods are essential; however, sampling costs and the practicalities of sampling have to be reasonable to allow testing on a large scale. In this study of 67 Salmonella-positive duck flocks, we assessed the suitability of several sample types. Different combinations of samples were also explored to produce advice on the most sensitive, yet practical sampling method. Overall, detecting all positive flocks proved challenging, and the number of samples collected from a flock appeared to influence the outcome rather than the actual type of sample. While a number of different sampling options proved successful to detect high prevalence flocks, low prevalence flocks were only detected satisfactorily if several sample types were taken and the results combined. It was concluded that the detection of Salmonella-positive breeding, laying or fattening duck flocks requires more samples compared to chicken or turkey flocks in order to achieve a meaningful outcome.