Abstract

Since the arrival of porcine epidemic diarrhea virus (PEDV) in the United States in 2013, elimination and control programs have had partial success. The dynamics of its spread are hard to quantify, though previous work has shown that local transmission and the transfer of pigs within production systems are most associated with the spread of PEDV. This particular study relies on the history of PEDV infections in a region of the southeastern United States. This infection data is complemented by farm-level features and extensive industry data on the movement of both pigs and vehicles. The researchers implemented a discrete-time survival model and evaluated different approaches to modeling the local-transmission and network effects. They found strong evidence that local transmission and pig-movement effects are associated with the spread of PEDV, even when controlling for seasonality, farm-level features, and the possible spread of disease by vehicles. The fully Bayesian model used permits full uncertainty quantification of these effects. The farm-level out-of-sample predictions of the model had a receiver-operating characteristic area under the curve (AUC) of 0.779 and a precision-recall AUC of 0.097. The quantification of these effects in a comprehensive model allows stakeholders to make more informed decisions about disease prevention efforts.