1. Experimental Zooprophylactic Institute of Sicily “A. Mirri”; Via Passo Gravina 195, Catania I-95123 Italy
2. Department of Biological, Geological and Environmental Science; University of Catania; Via Androne 81, Catania I-95124 Italy
3. Department of Biomedical and Biotecnological Sciences; University of Catania; Via Santa Sofia 97, Catania I-95123 Italy
4. Department “G.F. Ingrassia”; University of Catania; Via Santa Sofia, 87, Catania I-95123 Italy
5. National Research Council Institute for Agricultural and Forest Systems in the Mediterranean; National Research Council; Via Empedocle, 58, Catania I-95125 Italy