1. Agricultural Research Council—Onderstepoort Veterinary Institute, Pretoria 0110, South Africa
2. Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa
3. Department of Biochemistry, Microbiology & Genetics, University of Pretoria, Pretoria 0110, South Africa
4. Vetdiagnostix–Veterinary Pathology Services, Pietermaritzburg 3200, South Africa
5. Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, P/Bag X4, Pretoria 0110, South Africa