1. Agricultural Research Council—Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa
2. Department of Zoology & Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa
3. Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa
4. Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa