1. Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
2. CSIRO Health and Biosecurity, Australian Animal Health Laboratory (AAHL), Geelong, Victoria 3220, Australia
3. Department of Biochemistry and Molecular Biology, BIO21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
4. Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, 169857Singapore