Q fever as a cause of fever of unknown origin / 대한내과학회지

ABSTRACT

Q fever is an orthozoonotic infection caused by Coxiella burnetii, which was recently reclassified from the order Rickettsials to the order Legionellales. Although Q fever is usually mild and self-limiting, it may be manifested as a serious disease, such as pneumonia, endocarditis, or meningoencephalitis. We describe three separate cases of acute Q fever, which were diagnosed by an indirect micro-immunofluorescence assay (MIFA) test and DNA amplification (PCR). Three adult patients were admitted between December 2004 and August 2006 because of a fever of greater than three weeks duration. Only one patient had contact history with a dog. Of the three patients, two patients had myalgia, headache, skin rash, lymphadenopathy, and hepatosplenomegaly. Although all sets of blood cultures were negative, anti-phase II antibody titers by using an indirect MIFA (IgG 1512 - 1,024 and IgM 1320) were markedly increased in sera from all of three patients. Concomitant PCR assays also demonstrated the presence of OMP com1 for C. burnetii in blood from all of the three patients. Two patients had complete resolution of symptoms and signs with a two week course of doxycycline, while one patient had spontaneous defervescence. Although the incidence of Q fever is not well known yet in Korea, it should be considered in the differential diagnosis of patients with fever of unknown origin.