We found that protozoal infections were driven largely by Giardia, as 94.7% of subjects with a protozoal infection had Giardia. One possible mechanism by which helminths may increase susceptibility to protozoa is through the proinflammatory cytokine IFN-γ [45, 46], which is antagonized by the cytokine IL-4 triggered by helminth infection [15]. The gene discussed is IL4; the disease is helminthiasis.