[1] MERCK SHARP & DOHME RES LABS,VIRUS & CELL BIOL RES,W POINT,PA 19486
[2] UNIV GLASGOW,INST VIROL,MRC,VIROL UNIT,GLASGOW G11 5JR,SCOTLAND
[3] TUFTS UNIV,SCH MED,DEPT PATHOL,BOSTON,MA 02111
[4] CALIF DEPT HLTH SERV,VIRAL & RICKETTSIAL DIS LAB,BERKELEY,CA 94704
[5] UNIV COLORADO,SCH MED,DEPT NEUROL,DENVER,CO 80262
[6] UNIV IOWA HOSP & CLIN,DEPT PEDIAT,DIV INFECT DIS,IOWA CITY,IA 52242
[7] WISTAR INST ANAT & BIOL,PHILADELPHIA,PA 19104
[8] OSAKA UNIV,MICROBIAL DIS RES INST,DEPT VIROL,SUITA,OSAKA 565,JAPAN