2.1 Sample collection and processing
A total of 734 samples from various submitted sample types, including serum, pooled tissue samples, semen, feces, aborted fetuses, and oral fluids, were obtained from Chulalongkorn University, Veterinary Diagnostic Laboratory (CU-VDL) and Diagnostic Laboratory of ­­­­­­Large Animal Hospital and Students Training Center between January 2019 and December 2020. The samples were collected from 145 swine farms located in 18 provinces from different geographical regions of Thailand, mainly in the high pig density areas in the Western, Central, and Eastern parts (Figure S1). The experimental protocol was approved by the certification of the institutional biosafety committee of the Faculty of Veterinary Science, Chulalongkorn University (protocol number 2131007).