1. a Department of Veterinary Disease Biology, Faculty of Life Sciences , University of Copenhagen, Denmark , Ridebanevej 9, 1 - DK-1870 , Frederiksberg C , Denmark
2. b National Institute of Agricultural Research of Benin, 01 P.O. Box 884 , Cotonou , Benin
3. c Biochemistry and Molecular Biology Laboratory, Faculty of Sciences and Techniques, University of Abomey-Calavi, Benin, 04 P.O. Box 0320 , Cotonou , Bénin
4. d CIP-Benin, P.O. Box 08-0932 , Cotonou , Benin