A patient with chronic Q-fever will enter a multidisciplinary follow-up program. First, a PET/CT-scan will be provided (question; signs of an infected aneurysm/prosthesis)and chronic Q-fever endocarditis will be excluded. The patients will initially be treated with doxycycline 2 dd 100mg and plaquenil 200mg 3dd for at least 18 months. A 3-monthly follow-up will start, in which bloodsample, ultrasounds and PET/CTscan will be performed. Data will be collected in SPSS for analyses.