1. Department of Veterinary Services, Ministry of Agriculture and Livestock, P.O. Box 50060, Lusaka, Zambia
2. Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
3. Royal Veterinary College, London AL9 7TA, UK
4. Norwegian School of Veterinary Sciences, Ullevålsveien, P.O. Box 8146, 0033 Oslo, Norway
5. Onderstepoort Veterinary Institute, Agricultural Research Council, Old Soutpan Road, Onderstepoort, Pretoria 0110, South Africa
6. Sokoine University of Agriculture, P.O. Box 3297, Chuo Kikuuu, Morogoro, Tanzania