1. Department of Membrane and Ultrastructure Research, The Hebrew University-Hadassah Medical School, Jerusalem 91120,1 and
2. Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia 306022; and
3. Division of Avian and Aquatic Diseases, Kimron Veterinary Institute, Bet Dagan 50250,3 Israel;
4. Institute for Bacteriology, Mycology and Hygiene, Vienna University of Veterinary Medicine, A-1210 Vienna, Austria4