1. College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu P.O. Box 34, Ethiopia
2. Faculty of Veterinary Medicine, Hawassa University, Hawassa P.O. Box 05, Ethiopia
3. Animal Health Institute (AHI), Sebeta P.O. Box 04, Ethiopia
4. Department of Infectious Diseases, University of Naples, 80138 Naples, Italy