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

An interesting observation found during the course of this study was that a significant drop in the control parameter (d) was observed in generation four and then the control parameter appeared to rebound in subsequent generations. There is no obvious explanation for this observation however; this period of decreased "control" (and therefore a short period of epidemic acceleration between generation three and four) could be the result of environmental conditions. PEDV is a cold tolerant virus and it is believed that in Ontario, one way that the virus was spread between farms was on PEDV contaminated trucks [12, 13, 31] . Although Ontario implemented rigorous disinfection protocols for vehicles moving between farms, disinfection protocols are less effective in very cold temperatures as it is difficult to properly clean and dry trucks in freezing conditions allowing a cold tolerant virus to persist in the truck environment for longer periods of time and facilitating possible spread between premises [7, 12] .