Investigating the potential for disease spread, prevention, and control in the Ontario equine population

This thesis aims to investigate the potential for disease spread in the Ontario equine population, and to describe the implications for disease prevention and control. A series of research projects were undertaken to address existing knowledge gaps surrounding the Ontario equine population, including descriptions of horse characteristics, the nature and extent of horse movements, and the expected efficacy of common biosecurity practices. Questionnaires were used to describe horse characteristics (including age, vaccinations, and travel patterns), and facility characteristics (including number of boarded horses and their sport/competition disciplines). Network analysis was used to synthesize questionnaire responses to describe the connectivity between horses and horse facilities. Agent-based models were used to explore potential disease spread within the network of horse contacts, and to investigate the impact of biosecurity and infection control measures (i.e., vaccination, reduced horse-to-horse contact, and quarantine). There are several important findings from this thesis. First, descriptive analyses suggested that horse owners are currently vaccinating their horse(s) and reducing opportunities for direct and indirect horse contact. In particular, owners with horses that participated in competitive disciplines reported higher levels of vaccine coverage for various equine pathogens, compared to owners with horses that participated in either leisure or racing activities. Second, agent-based models demonstrated the importance of using multiple biosecurity and infection control measures in combination. The most effective strategies to minimize the extent of a simulated outbreak were those that combined disease prevention (e.g., increased vaccine coverage) with disease control (e.g., quarantine upon returning home from a competition). Third, participants reported travelling frequently with their horse(s) to attend various competitions, training clinics, and leisure activities. The description of horse movement patterns provides valuable data that can contribute to future research exploring the characteristics of highly connected horses and facilities. The combined approach of questionnaires, network analysis, and simulation models has provided insight into the Ontario equine population, which can better inform the use of effective disease prevention and control strategies. This thesis represents a fundamental contribution to the ongoing discussion within the Ontario equine industry regarding the refinement of existing disease prevention and control strategies.