Modelling Salmonella transmission among pigs from farm to slaughterhouse: Interplay between management variability and epidemiological uncertainty.
Salmonella carriage and cutaneous contamination of pigs at slaughter are a major risk for carcass contamination. They depend on Salmonella prevalence at farm, but also on transmission and skin soiling among pigs during their journey from farm to slaughterhouse. To better understand and potentially control what influences Salmonella transmission within a pig batch during this transport and lairage step, we proposed a compartmental, discrete-time and stochastic model. We calibrated the model using pork chain data from Brittany. We carried out a sensitivity analysis to evaluate the impact of the variability in management protocols and of the uncertainty in epidemiological parameters on three model outcomes: prevalence of infection, average cutaneous contamination and number of new infections at slaughter. Each outcome is mainly influenced by a single management factor: prevalence at slaughter mainly depends on the prevalence at farm, cutaneous contamination on the contamination of lairage pens and new infections on the total duration of transport and lairage. However, these results are strongly affected by the uncertainty in epidemiological parameters. Re-excretion of carriers due to stress does not have a major impact on the number of new infections.
MaIAGE, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France. Electronic address: jordi.ferrer.savall@gmail.com.
Jordi
J
Ferrer Savall
MaIAGE, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
Caroline
C
Bidot
INRA, LUNAM Université, Oniris, UMR 1300 BioEpAR, 44300 Nantes, France.
Mily
M
Leblanc-Maridor
INRA, LUNAM Université, Oniris, UMR 1300 BioEpAR, 44300 Nantes, France.
Catherine
C
Belloc
INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254 Institut Sophia Agrobiotech, 06900 Sophia Antipolis, France; BIOCORE, Inria, 06900 Sophia Antipolis, France.
Suzanne
S
Touzeau
D000003:Abattoirs / Q000592:standards; D000822:Animal Husbandry / Q000592:standards; D000818:Animals; D000072480:Farms / Q000592:standards; D005506:Food Contamination / Q000517:prevention & control; D008460:Meat / Q000382:microbiology; D008954:Models, Biological; D015995:Prevalence; D012475:Salmonella; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000635:transmission*; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000635:transmission*
Salmonellosis; Sensitivity analysis; Stochastic model; Swine; Transport and lairage