Insight into the epidemiology of swine dysentery by analyzing treatment records and using simulation modelling

This thesis describes Brachyspira species infection dynamics in a population of growing pigs, including the clinical manifestation of the infection known as swine dysentery (SD). Using production data from a clinically infected herd, intramuscular treatments with tiamulin and lincomycin were considered to be indicative of swine dysentery. Risk factors for the treatment rates were determined. In addition, important parameters were extracted from the literature and the treatment data and were used to replicate SD progression in a herd through deterministic modelling. Parameters that are most associated with mortality due to clinical SD were identified using sensitivity analysis. Finally, a stochastic compartmental model was developed to describe Brachyspira infection and SD clinical disease within a herd. Treatment and production costs were also incorporated into the model to identify the most cost-effective treatment protocol for this disease.