Improvement of chronic nonspecific symptoms by long-term minocycline treatment in Japanese patients with Coxiella burnetii infection considered to have post-Q fever fatigue syndrome

Objective To address the presence of post-Q fever fatigue syndrome (post-QFS) in Japan, and to evaluate the efficacy of minocycline for this condition. Patients and Methods In 20 Coxiella burnetii (C burnetii) seropositive patients with persistent nonspecific symptoms including general fatigue, low-grade fever, myalgia and arthralgia, changes in subjective symptoms, C burnetii antibody titers and C burnetii DNA were evaluated after antibiotic treatment. Results After treatment mainly with minocycline (100 mg/day for 3 months), the clinical picture improved in all 20 patients as evidenced by decreases in body temperature (13/17), general fatigue (20/20) and headache (9/12). The mean performance status (PS) score improved from 5.0 to 1.8 (p < 0.01). All 7 who had been positive for C burnetii DNA, became negative together with an improvement in subjective symptoms. Indirect immunofluorescence tests demonstrated 6 of the 20 patients to be positive for C burnetii IgM antibody to phase II antigen (1 : 32), and 18 to be positive for IgG antibody (I : 128, 1 : 256). Antibody titers of both IgM (6/6, 1 : 16) and IgG (18/18, 1 : 16) decreased markedly after treatment. Conclusion These results of an open label study in Japan suggest that minocycline administration is useful for improving chronic nonspecific symptoms considered to be post-Q fever fatigue syndrome caused by C. burnetii infection.