Q fever infectious endocarditis. Apropos of a new case

We report a case of Coxiella burnetii endocarditis in a 42-year old man presenting with a long-known cardiac murmur and an infectious syndrome of several months duration. The aetiological diagnosis, delayed by the lack of knowledge of a primary Q fever, was established by serology. The infection responded to tetracycline combined with cotrimoxazole, but a valve replacement performed for haemodynamic reasons was followed by serious complications. We remind the readers that Q fever endocarditis must be considered as a possible diagnosis in all cases of endocarditis with negative blood cultures and that specific serological examinations in search of anti-phase I antibodies of the IgA type should be performed as soon as possible, using the indirect immunofluorescence technique. Attention is drawn to the different serological responses of the three clinical types of Q fever infection and to the cellular immunity associated with that disease.