[1] USDA, ARS, Anim & Nat Resources Inst, Anim Parasit Dis Lab, Beltsville, MD 20705 USA
[2] Illinois Dept Agr, Anim Dis Lab, Galesburg, IL 61402 USA
[3] All Pets Vet Clin, Macomb, IL 61455 USA
[4] Ohio State Univ, Dept Mol Genet, Columbus, OH 43210 USA
[5] Ohio State Univ, Dept Ecol Evolut & Organismal Biol, Columbus, OH 43210 USA
[6] Natl Ctr Infect Dis, Div Parasit Dis, Ctr Dis Control & Prevent, Atlanta, GA 30341 USA