This study was partially supported by a grant from Par? State Secretary of Science and Technology, contract no. 067/2008 (SEDECT/FAPESPA/PA).; Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil.; Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil.; Minist?rio da Agricultura. Laborat?rio Nacional Agropecu?...