Researchers from five countries across Europe, led by S. Van Hoorebeke of Ghent University in Belgium, surveyed layer farms prior de-population to determine risk factors for contamination with various Salmonella serotypes. Their paper has been published in Preventative Veterinary Medicine.

Van Hoorebeke and co-authors explain that salmonella outbreaks in humans are often linked to the consumption of contaminated eggs. Therefore knowledge of the current prevalence of Salmonella spp. in laying hens and the factors that influence the presence and persistence of Salmonella on a farm are of utmost importance.

The housing of laying hens in conventional battery cages will be forbidden in the European Union (EU) from 2012 onwards. There is an urgent need to evaluate whether this move to alternative housing systems will influence the prevalence of Salmonella in laying hens. Therefore, a cross-sectional study was performed in five European countries (Belgium, Germany, Greece, Italy and Switzerland) to determine the between- and within-flock prevalence of hens shedding Salmonella and to investigate whether there is an effect of the housing type on Salmonella prevalence, the research group added.

In total, they sampled 292 laying hen farms in the month prior to depopulation. An on-farm questionnaire was used to collect information on general management practices and specific characteristics of the sampled flock.

Twenty-nine flocks were found positive for at least one Salmonella-serotype.

In these flocks, the within-flock prevalence of shedding hens, determined by individual sampling of 40 hens, varied between zero and 27.50 per cent.

A wide variety of serotypes was isolated with Salmonella Enteritidis being the most common.

Housing in conventional battery cages, the absence of dry cleaning in between production rounds and sampling in winter turned out to be risk factors for the shedding of Salmonella Enteritidis or Typhimurium (P<0.05).

Reference

Van Hoorebeke S., F. Van Immerseel, J. Schulz, J. Hartung, M. Harisberger, L. Barco, A. Ricci, G. Theodoropoulos, E. Xylouri, J. De Vylder, R. Ducatelle, F. Haesebrouck, F. Pasmans, A. de Kruif and J. Dewulf. 2009. Determination of the within and between flock prevalence and identification of risk factors for Salmonella infections in laying hen flocks housed in conventional and alternative systems. Preventative Veterinary Medicine. doi:10.1016 / j.prevetmed.2009.11.022

Further Reading

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