Neighbor-joining (A) and parsimony (B) trees based on the hypervariable region of the 18S rRNA gene (created with PAUP 4.0 software). C. felis was designated an outgroup. Evolutionary distances were determined by the Kimura two-parameter method. GenBank accession numbers of sequences included in the trees are AB089285 (C. andersoni), L19068 (C. baileyi), AF112575 (C. felis), AF112574 (C. meleagridis), L19069 (C. muris bovine genotype), AB089284 (C. muris murine genotype), AF093489 (C. parvum human genotype), AF093493 (C. parvum bovine genotype), AF112571 (C. parvum mouse genotype), AF112572 (C. parvum ferret genotype), AF115377 (C. parvum pig genotype), AF112576 (C. parvum dog genotype), AF112570 (C. parvum kangaroo genotype), AF093499 (C. serpentis), U11440 (C. wrairi), AY324634 (cormorant), AY324635 (goose no. 1), AY324636 (goose no. 2), AY324637 (goose no. 3 [sequence a]), AY324638 (goose no. 3 [sequence b]), AY324639 (goose no. 5), AY324640 (goose no. 6), AY324641 (goose no. 7), AY324642 (goose no. 8), and AY324643 (goose no. 9). Bootstrap values greater than 50% are indicated in bold at each respective node.