The Authors relate a case ofsevere schistosomiasis mansoni (hepatic form, with portal hypertension, associated with pulmonary form, with pulmonary hypertension and cor pulmonale), o ver which develloped a severe toxi-infectious syndrome of long duration. Serial chest X-rays showed that the arteriolae were predominantly affected, besides a gross and difuse pulmonary micronodulation in both hemithoraces, and pulmonary heart configuration. Histopathology of the pulmonary biopsy material identified basically a pulmonary arteritis characteristic of chronic pulmonary schistosomiasis and, simultaneously, the presence of schistosomatous granulomata in hyperergic reaction mainly produced by worms, one of the main anatômica! characteristics of the toxemic form. To explain the origin of the clinical toxi- infectious constelation, the hypotheses of an association with a co-existing infectious, or not infectious but fever producing cause, and of the superposition of a toxemic form over a pre-existing chronic one were eliminated. It was concluded, on the basis of clinical data, particularly those furnished by laparoscopy and the anatomical onas, that this a chronic case of schistosomiasis reactivated probably by the host uncommon immunological alteration. Everything points to the possibility that the unusual detour of the eggs, and of the worms to the lungs was due to the portal hypertension syndrome, and that the preferential route of this migration was determined by the shunts involving the portal and systemic circulations.