IL4 and viral infectious disease: Of note, the type 2 cytokines such as IL-4, IL-5, IL-10 and IL-13 were reduced in coinfected mice when compared to S. mansoni-infected mice suggesting a reciprocal effect of LCMV on anti-helminth immune responses.68S. mansoni infection also impaired immune responses against systemic infection with vaccinia virus resulting in enhanced viral burden (Table 3).69 Thus, helminths can impair host immune responses to viral infections through local or systemic effects.