1. Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
2. Institute of Agricultural Research for Development (IRAD), P.O. Box 2067, Yaounde, Cameroon
3. CIRAD, UMR ABSys, University Montpellier, TA B-34/02-Avenue Agropolis-34398, CEDEX 5 Montpellier, France
4. International Institute of Tropical Agriculture (IITA), BP 2008, Yaounde-Messa, Cameroon