Here, we have generated a Trem1−/− mouse to unambiguously investigate the impact of a complete TREM-1-deficiency on the pathogenesis of experimental colitis but also of two other distinct sub-acute disease settings where the role of TREM-1 has so far not been addressed in vivo, i.e. inflammation induced by a parasitic and viral infection. This evidence concerns the gene TREM1 and viral infectious disease.