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

We conducted sensitivity analyses to examine alternate assumptions about the possible impact of a generation time that was greater than the base case estimate of seven days (7-13 days) . In this case, we refit our model using 8-, 9-, 10-, 11-, 12-, and 13-day generation times. For each model fit, we examined the impact of the updated generation time on the estimated R 0 and d parameters. In addition, we considered the possible impact of under-reporting in the OMAFRA dataset. In our base case analysis, we assumed no under-reporting of cases. Given the emerging nature of the disease in Ontario as well as the clinical and economic severity of the disease this seemed a reasonable assumption to make. However, an alternative assumption exists which is that the dataset represents only the initial/index case within individual production systems (with some production systems being comprised of many individual farms or premises). To address the possibility of under-reporting in the dataset, we have fit the model examining a range of possible assumptions related to under-reporting (from 0% to 50% under-reporting).