[1] Univ Liege, Fac Med Vet, B-4000 Liege, Belgium
[2] Prince Leopold Inst Trop Med, Anim Hlth Dept, B-2000 Antwerp, Belgium
[3] Walloon Agr Res Ctr, Dept Biol Control & Plant Genet Resources, B-5030 Gembloux, Belgium
[4] Univ Strasbourg 1, Inst Parasitol & Trop Pathol, F-67000 Strasbourg, France
[5] CIRAD, F-34398 Montpellier, France
[6] Gembloux Agr Univ, B-5030 Gembloux, Belgium