Estimating the potential for disease spread in horses associated with an equestrian show in Ontario, Canada using an agent-based model.

The research article assesses the potential for disease spread, specifically equine influenza, among horses at an equestrian show in Ontario, Canada, using an agent-based model. The study also examines the effectiveness of various interventions to control disease spread during a simulated outbreak.

Study Objectives and Methodology

• The study had two main objectives. The first was to analyze the potential spread of equine influenza resulting from the two-day equestrian show. The second was to determine the effectiveness of several control and preventive strategies in a simulated outbreak scenario.
• To fulfill these objectives, a discrete-event continuous-time stochastic agent-based simulation model was created. This model represented horses associated with the show, whether in attendance at the event, or those co-boarded with attending horses but not physically present at the show.
• The simulation was started by infecting one arbitrary horse in attendance with equine influenza, then observing the potential outbreak effect without interventions.

Findings without Interventions

• Without any interventions, the median attack rate (probability of horses in the population getting infected) was found to be 0.029, with the attack rate ranging from 0.016 to 0.056 in most cases. The mean attack rate was 0.043.
• The average duration of outbreak under these circumstances was found to be just under 20 days.

Effectiveness of Interventions

• A 5-day or 14-day quarantine was found to be the most effective intervention. This drastically reduced the median attack rate to 0.0026. However, the mean attack rates differed slightly for both quarantine durations.
• In situations where a 5-day or 14-day quarantine wasn’t feasible, a shorter quarantine combined with a targeted increase in initial vaccine coverage at the facility level was found to be effective.
• For instance, the combination of a 2-day quarantine and vaccine coverage of 75% in facilities housing four or more owners resulted in a reduced median attack rate of 0.013.

Application of Research Findings

• This research provides a relative comparison of the effectiveness of various interventions during a simulated equine influenza outbreak following an equestrian show.
• The findings may prove invaluable in informing and improving the current strategies meant to prevent and control the spread of diseases within the horse population.