1. Malaria Department, OCEAC, Yaoundé, Cameroun,
2. Department of Animal Biology and Physiology, University of Yaoundé I, Cameroun ,
3. Microbiology Department, University of Nijmegen, The Netherlands,
4. LAF 302, Laboratoire Associé Francophone, Cameroun;,
5. ORSTOM, Institute Français de Recherche Scientifique pour le devélopment en coopération, Paris, France