1. Institut Ruder Bošković, Division of Molecular Medicine, 10000 Zagreb, Croatia
2. Poultry Center, Croatian Veterinary Institute, 10000 Zagreb, Croatia
3. Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3044
4. CSIRO, Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
5. Department of Medical Microbiology, Turku University, FIN-20520 Turku, Finland
6. Institut Ruder Bošković, Division of Molecular Medicine, 10000 Zagreb, Croatia, and Department of Avian Medicine, University of Georgia, Athens, GA 30602-4875