1. Laboratory of Parasitology and Parasitic Diseases, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
2. M.R.W.-D.G.R.N.E., Direction des Cours d'Eau non navigables, Service de Piégeage des rats musqués 15, avenue Prince de Liège B-5100 Jambes, Belgium