1. Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt
2. Institute of Parasitology and Tropical Veterinary Medicine, Faculty of Veterinary Medicine, Free University of Berlin, 14195 Berlin, Germany
3. Boehringer Ingelheim Svanova, Uppsala Business Park, P.O. Box 1545, 75145 Uppsala, Sweden