Schistosoma mansoni infection is associated with a reduced course of asthma.

Background: Helminthic infections decrease skin reactivity to indoor allergens, but data on whether they influence asthma severity are lacking.

Objective: This study evaluated the course of asthma in patients with and without Schistosoma mansoni infection.

Methods: Asthmatic subjects were enrolled from 3 low-socioeconomic areas: a rural area endemic for schistosomiasis (group 1) in addition to a rural area (group 2) and a slum area (group 3), both of which were not endemic for schistosomiasis.