These mechanisms are supported by our current observations, including observation of blood in faeces from some of the infected mice at several time points from day 48 post-infection onwards, spleen enlargement in all the S. mansoni-infected mice on dissection (histological evidence was reported in a previous study [14]) and elevated levels of several cytokines, such as interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-5 and IL-12 in plasma in response to the infection [22]. The gene discussed is IL4; the disease is infection.