TREM1 and infection: Hence, while Tnf−/− or anti-TNF-treated mice exhibit an aggrevated acute DSS-induced colitis [39], [40] and also show enhanced parasite and bacterial burdens upon infection with L. major and L. pneumophila, respectively [41], [53], Trem1−/− mice appeared equally capable of controlling a parasitic, viral and bacterial infection as Trem1+/+ controls.