We did not observe the Dar phenotype in uninfected tph-1 mutants or in wild type animals treated with methiothepin (R. McMullan and A. Anderson, unpublished observation) indicating that infection with M. nematophilum must regulate additional signaling pathways (including the EGL-30(Gαq) pathway) to trigger the immune response. The gene discussed is TPH1; the disease is infection.