This project received partial federal support from the Evandro Chagas Institute/Brazilian Ministry of Health. This research was also partially financed by FAPESP (S?o Paulo Research Foundation) through Grant 02/9546-1 and CNPq (National Council for Scientific and Technological Development) through Grant 302353/2003-8; Universidade Federal de Goi?s. Instituto de Patologia Tropical e Sa?de P?blica. Goi?nia, GO, B...