[1] ROYAL VET & AGR UNIV,DEPT VET VIROL & IMMUNOL,DK-1870 FREDERIKSBERG C,DENMARK
[2] INST NACL INVEST AGR,DEPT SANIDAD ANIM,E-28012 MADRID,SPAIN
[3] USDA ARS,HELMINTH DIS LAB,BELTSVILLE,MD 20705
[4] INDIANA UNIV,DEPT SURG MICROBIOL IMMUNOL,INDIANAPOLIS,IN 46202
[5] ACAD SCI CZECH REPUBL,INST MICROBIOL,DEPT IMMUNOL,CR-14220 PRAGUE,CZECH REPUBLIC
[6] INRA,IMMUNOL LAB,F-37380 MONNAIE,FRANCE
[7] UNIV ZAGREB,FAC VET,DEPT BIOL,ZAGREB 41000,CROATIA
[8] UNIV ILLINOIS,COLL VET MED,DEPT VET PATHOBIOL,URBANA,IL 61801