1. Department of Production Animal Studies Faculty of Veterinary Science University of Pretoria Onderstepoort South Africa
2. Vaccines and Diagnostics Programme Agricultural Research Council‐Onderstepoort Veterinary Research Onderstepoort South Africa
3. School of Veterinary Medicine Faculty of Medical Sciences The University of the West Indies St. Augustine Trinidad and Tobago
4. Diagnostic Service Programme Agricultural Research Council‐Onderstepoort Veterinary Research Onderstepoort South Africa