A within-flock model of Salmonella Heidelberg transmission in broiler chickens
Autor: | Lucie Collineau, Ben A. Smith, Brennan Chapman, Aamir Fazil, Charly Phillips, Agnes Agunos, Richard J. Reid-Smith, Carolee A. Carson |
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Rok vydání: | 2020 |
Předmět: |
Canada
Veterinary medicine 040301 veterinary sciences animal diseases 030231 tropical medicine Biology law.invention 0403 veterinary science 03 medical and health sciences 0302 clinical medicine Food Animals Microbial risk law Prevalence Animals Poultry Diseases Feces Salmonella Infections Animal Incidence (epidemiology) Salmonella Heidelberg Broiler 04 agricultural and veterinary sciences Models Theoretical Transmission (mechanics) Animal Science and Zoology Flock Chickens Barn (unit) |
Zdroj: | Preventive Veterinary Medicine. 174:104823 |
ISSN: | 0167-5877 |
DOI: | 10.1016/j.prevetmed.2019.104823 |
Popis: | As part of the development of a quantitative microbial risk assessment (QMRA) model of third-generation cephalosporins (3GC)-resistant Salmonella Heidelberg, a compartmental (SEIR) model for S. Heidelberg transmission within a typical Canadian commercial broiler chicken flock was developed. The model was constructed to estimate the within-flock prevalence and the bacterial concentration in the barn environment at pre-harvest, and to assess the effect of selected control measures. The baseline scenario predicted an average within-flock prevalence of 23.5 % (95 % tolerance interval: 15.7-31.4) and an average bacterial concentration of 3.579 (0-4.294) log CFU/g of feces in the barn environment at pre-harvest (on the day the flock is sent to slaughter). Because vertical introduction of S. Heidelberg into the barn was already uncommon in the baseline scenario, vaccination of broiler parent flocks appeared to have a negligible effect, while vaccination of broiler chicken flocks substantially reduced the bacterial concentration at pre-harvest. Cleaning and disinfection between batches markedly reduced the within-flock prevalence at pre-harvest, but the effect on bacterial concentration was limited outside of the beginning of the production period. Extending downtime between batches by 7 days had little effect on within-flock prevalence or bacterial concentration of S. Heidelberg when compared to the baseline scenario. This study provides a basis to describe S. Heidelberg dynamics within a broiler chicken flock and to predict the within-flock prevalence and bacterial concentration at pre-harvest, and includes a description of the limitations and data gaps. The results of these analyses and associated uncertainties are critical information for populating QMRA models of the downstream impacts on public health from on-farm and other food-chain practices. Specifically, the study findings will be integrated into a broader farm-to-fork QMRA model to support the risk-based control of S. Heidelberg resistant to 3GC in broiler chicken in Canada. |
Databáze: | OpenAIRE |
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