Vet. Res. (2008) 39:20
DOI: 10.1051/vetres:2007058

Effect of genetic resistance of the hen to Salmonella carrier-state on incidence of bacterial contamination: synergy with vaccination

Kevin Prévost^{1, 2}, Pierre Magal¹, Jocelyne Protais³ and Catherine Beaumont<sup>2

1</sup>  Faculté des Sciences et Techniques, Université du Havre, 76085 Le Havre, France
²  INRA, Département de Génétique Animale, Station de Recherches Avicoles, 37380 Nouzilly, France
³  AFSSA, Laboratoire Central de Recherches Avicoles et Porcines et Piscicoles, Unité "Hygiène et Qualité des Produits Avicoles et Porcines", BP 53, 22440 Ploufragan, France

(Received 23 February 2007; accepted 18 September 2007; published online 29 January 2008)

Abstract - Salmonella is one of the major sources of toxi-infections in humans. The association between egg consumption and Salmonella outbreaks is a serious economic and public health problem. To control the incidence of Salmonella in poultry flocks, many prophylactic means have been developed but none allows a total reduction of the risk. In a previous study, we derived mathematical models for Salmonella transmission and used them to appreciate the most important factors of variation of egg contamination rate and thus of risk of human contamination. Thanks to recent data of a selection experiment for increased or decreased rate of carrier-state (also called divergent selection), we showed that mixing, in an equal proportion, animals issued from a line selected for a lower (denoted Sal-) or higher propensity to carry Salmonella (denoted Sal+) results in a reduction by half of the maximal percentage of contaminated animals but does not accelerate the extinction of the disease. Vaccination and selection should be synergic, since a former contamination reduces the maximal prevalence by 45 and 71%, respectively, in Sal+ or Sal- flocks respectively. These results show the interest in the introduction, even at a rather moderate percentage, of animals selected for a reduced rate of Salmonella carrier-state within commercial flocks. This could be achieved by using one or more selected lines in commercial crosses. These results must be confirmed experimentally while the mathematical model could be extended with minor modifications to other animal species or pathogenic species.

Key words: Salmonella / mathematical model / genetic / resistance / vaccination

Corresponding author: kevin.prevost849@univ-lehavre.fr

© INRA, EDP Sciences 2008