[1] Univ Nacl Autonoma Mexico, Fac Med, Mexico City, DF, Mexico
[2] Hosp Gen Dr Manuel Geo Gonzalez, Secretaria Salud, Mexico City, DF, Mexico
[3] IPN, CINVESTAV, Lab Inmunol & Biol Mol, Unidad Merida, Merida, Yucatan, Mexico
[4] Int Livestock Res Inst, People Livestock & Environm Programme, Nairobi, Kenya
[5] Royal Vet & Agr Univ, WHO FAO Collaborating Ctr Parasit Zoonoses, Fredericksburg, VA USA