The balance between T cell response and parasite load determines the disease outcome of mice infected with different E. multilocularis inocula [47]; and a stronger expression of programmed cell-death receptors (PDCD1, 2B4 and LAG3) associated with “exhausted” parasite antigen induced T cell responses and an enhanced E. multilocularis metacestode growth at the late stages of infection [47]. The gene discussed is PDCD1; the disease is infection.