LOS showing TLR4 antagonist activity from Bartonella quintana (BqLOS) was recently identified (Figure 3). B. quintana was initially described during World War I as the causative agent of trench fever. B. quintana is present in the bloodstream of patients during the febrile stage of trench fever; indeed, bacteremia can persist longer after the disappearance of all clinical signs [41, 42]. The gene discussed is TLR4; the disease is trench fever.