Co-infection with Ascaris lumbricoides modulates protective immune responses against Giardia duodenalis in school Venezuelan rural children

▶ We studied the effect of A. lumbricoides co- infection on the course of giardiasis. ▶ A group of 251 rural and 70 urban school children was evaluated. ▶ Moderate A. lumbricoides intensities correlated with a high prevalence of giardiasis. ▶ G. duodenalis stimulated TH2/TH1 immunity only in Ascaris lightly infected children. ▶ Moderate worm burdens decreased G. duodenalis immunity favoring recurrent infection.