J.B. Githiori1,2, Johan Höglund1, P.J. Waller1, R. L. Baker2
1Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, SE-751 89 Uppsala, Sweden
2International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya