1. Agriculture and Agrifood Canada, Health of Animals Laboratory/Saskatoon, 116 Veterinary Road, University of Saskatchewan Campus, Saskatoon, Saskatchewan S7N 5E3, Canada
2. Agriculture and Agrifood Canada, Animal Diseases Research Institute/Lethbridge, P.O. Box 640, Lethbridge, Alberta T1J 3Z4, Canada
3. Inter-American Institute for Co-operation in Agriculture, Office in Trinidad and Tobago, The Apple Complex, 155-157 Tregarele Road, Woodbrook, Port of Spain, Trinidad and Tobago