1 Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica.
2 Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel.
3 Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica; Laboratory of Helminthology, Faculty of Microbiology, University of Costa Rica, San José, Costa Rica. Electronic address: anaalicia.rojas@ucr.ac.cr.