1. Department of Morphology, Faculty of Veterinary Medicine; Ghent University; Merelbeke; Belgium
2. Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine; Ghent University; Merelbeke; Belgium
3. Laboratory of Aquaculture and Artemia Reference Center; Ghent University; Ghent; Belgium
4. Department of Basic Sciences, College of Veterinary Medicine; Mississippi State University; Mississippi; USA