IL5 and infection: Filarial fertility is clearly controlled by Th2 responses as infections of ΔdblGata1 (eosinophil deficient) and Il-4ra-/-/Il-5-/- (wider Th2 deficiency including defect in macrophage alternative activation) BALB/c mice result in 80 to 100% Mfpos mice [23] with 10 to 35 times higher microfilaremia.