1. Department of Population Health and Reproduction, University of California Davis School of Veterinary Medicine, Davis, California.
2. Institut de la Recherche Vétérinaire de Tunisie, Laboratoire de Parasitologie et des Maladies des Abeilles, Tunis, Tunisia.
3. Department of Pathology, Microbiology and Immunology, University of California Davis School of Veterinary Medicine, Davis, California.
4. Université Paris-Est, Ecole Nationale Vétérinaire d'Alfort, UMR BIPAR ENVA-Anses-INRA, Maisons-Alfort, France.