[1] INT LAB RES ANIM DIS, NAIROBI, KENYA
[2] WASHINGTON STATE UNIV, PULLMAN, WA 99164 USA
[3] UNIV WISCONSIN, MADISON, WI 53706 USA
[4] MED HSCH HANNOVER, W-3000 HANNOVER 61, GERMANY
[5] PENN STATE UNIV, UNIVERSITY PK, PA 16802 USA
[6] VET SCH, IMMUNOL UNIT, W-3000 HANNOVER 1, GERMANY
[7] FAC UNIV NOTRE DAME PAIX, IMMUNOL UNIT, B-5000 NAMUR, BELGIUM