[1] Univ Calif Davis, Davis, CA 95616 USA
[2] Univ Calif Davis, Sch Vet Med, Dept Med & Epidemiol, Davis, CA 95616 USA
[3] Univ Calif Davis, Davis Med Ctr, Sch Med, Div Gen Med, Sacramento, CA 95814 USA
[4] Univ Calif Davis, Comp Assisted Learning, Off Dean, Davis, CA 95616 USA
[5] Univ Utrecht, Fac Med Vet, Dept Parasitol & Trop Vet Med, NL-3508 TC Utrecht, Netherlands
[6] Univ Pretoria, Fac Vet Sci, Dept Trop Vet Dis, ZA-0110 Onderstepoort, South Africa
[7] Univ Glasgow, Fac Med Vet, Inst Comparat Med, Glasgow G61 1QH, Lanark, Scotland
[8] Univ Minnesota, Coll Vet Med, Dept Vet & Biomed Sci, St Paul, MN 55108 USA
[9] Michigan State Univ, Coll Vet Med, Populat Med Ctr, E Lansing, MI 48824 USA
[10] Washington State Univ, Coll Vet Med, Field Dis Invest Unit, Pullman, WA 99164 USA
[11] Iowa State Univ, Coll Vet Med, Ctr Food Secur & Publ Hlth, Ames, IA 50013 USA
[12] Univ Calif Davis, Sch Vet Med, Dept Pathol Microbiol & Immunol, Davis, CA 95616 USA