1. Department of Public Health, Pharmacology and Toxicology, University of Nairobi, P. O. Box 29053-00200, Nairobi, Kenya
2. Department of Veterinary Pathology, Microbiology, and Parasitology, University of Nairobi, P. O. Box 29053-00200, Nairobi, Kenya
3. Department of Clinical Studies, University of Nairobi, P. O. Box 29053-00200, Nairobi, Kenya