1. School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia.
2. Zambia Wildlife Authority, P.O. Box 830124, Chilanga, Zambia.
3. Norwegian School of Veterinary Sciences, Department of Basic Sciences and Aquatic Medicine, Section of Aquatic Medicine and Nutrition, Ullevalsveien 72, P.O Box 8146 Dep, NO-0033 Oslo, Norway.