Acknowledgments
Nguyen Manh Tuong was granted by an Asean scholarship from Chulalongkorn University. Chutchai Piewbang was granted by the Ratchadaphisek Somphot Fund for Postdoctoral Fellowship, Chulalongkorn University. This study was supported by the 90th Anniversary of Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund) and Veterinary Pathogen Bank, Faculty of Veterinary Science, Chulalongkorn University.