Understanding the early dynamics of the 2014 porcine epidemic diarrhea virus (PEDV) outbreak in Ontario using the incidence decay and exponential adjustment (IDEA) model

Greer, Amy L.; Spence, Kelsey; Gardner, Emma

Using a simple mathematical model that considers only two parameters, we have demonstrated that the epidemic growth of the 2014 swine PEDV outbreak in Ontario, Canada was to be expected with a reproductive number that exceeded one. However, our analyses also demonstrated that the outbreak began to quickly decelerate (d > 0) as a result of enhanced disease control efforts relatively quickly. Our successful application of the IDEA model to a case study of livestock infectious disease outbreak data is encouraging and suggests that despite some critical differences in the interpretation of the key model parameters and in the individual unit of study (farms/herds/premises vs. individuals), the model can provide useful information for decision-makers in the early stages of an infectious disease outbreak. We encourage the veterinary epidemiology community to continue to assess the usefulness of this simple model in the context of other emerging diseases of veterinary importance. In the case of real-time application and use of the model within an emergency management context, it is our hope that the model may be able to allow for the rapid identification of whether or not interventions are working to control the epidemic spread of the disease.