1. Department of Veterinary Science, Food and Consumer Sciences, Faculty of Agriculture, University for Development Studies, P.O. Box TL 1882, Nyankpala Campus, Tamale, NS-145-8637, Ghana
2. Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Glasgow G61 1QH, Scotland, UK