1. Provincial Veterinary Office, Ministry of Livestock and Fisheries, P.O. Box 910034, Mongu 10106, Zambia
2. Department of Clinical Studies, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka 10101, Zambia
3. Department of Disease Control, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka 10101, Zambia
4. Section of Aquatic Medicine and Nutrition, Department of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Sciences, Ullevålsveien 72, P.O Box 8146 Dep, 0033 Oslo, Norway