1. Department of OphthalmologyHokkaido University Graduate School of MedicineKita 15, Nishi 7, Kita-kuSapporo 060-8638, Japan
2. Veterinary Medical Research InstituteHungarian Academy of SciencesP.O. Box 18 H-1581Budapest, Hungary
3. MRC-University of Glasgow Centre for Virus Research8 Church StreetGlasgow G11 5JR, United Kingdom
4. Clinical Virology UnitCEMIC University HospitalGalvan 4102 (1431 FWO)Buenos Aires, Argentina
5. Centers for Disease Control and PreventionAtlanta, Georgia 30303
6. Lovelace Respiratory Research Institute2425 Ridgecrest Drive SEAlbuquerque, New Mexico 87108
7. University of Umeå,S-901 85 Umeå, Sweden