Schistosoma mansoni: permanence of modulation of the granulomatous inflammatory response in mice cured in the chronic phase.

Persistence of down regulation of granuloma size was studied in mice chronically infected with Schistosoma mansoni and cured by chemotherapy. The animals were reinfected at 20-, 50-, 110-, and 140-day intervals after treatment, and sacrificed 60 days post-infection. Reinfected animals were able to modulate the granulomatous inflammatory response, thus preventing a new acute phase. These findings may contribute to the explanation for the decrease of morbidity from human schistosomiasis seen in endemic areas following mass treatment.