1. Noguchi Memorial Institute for Medical Research; University of Ghana; Legon Ghana
2. Veterinary Services Directorate; Ministry of Food and Agriculture; Accra Ghana
3. Center for Epidemiology and Department of Large Animal Clinical Sciences; College of Veterinary Medicine; Michigan State University; East Lansing MI 48821 USA
4. Department of Pathobiology & Diagnostic Investigation; College of Veterinary Medicine; Michigan State University; East Lansing MI 48821 USA