1. Instituto de Ciências Biomédicas de Abel Salazar; University of Porto; Largo Professor Abel Salazar, 2 4099-003 Porto Portugal
2. Clinic of Companion Animals; Utrecht University; PO Box 80125 3508 TC Utrecht The Netherlands
3. Institute of Molecular Pathology and Immunology of the University of Porto; Rua Dr Roberts Frias s/n 4200-465 Porto Portugal