Abstract:

Objective To analyze the epidemiology, clinical pictures, diagnosis and treatment of acute Q fever in order to provide reference for the diagnosis and treatment of this entity. Methods Retrospective study was conducted on the 6 cases of acute Q fever diagnosed by metagenomics next-generation sequencing (mNGS) in Nantong Third People’s Hospital between May 2022 and August 2023. The data were collected and analyzed including the epidemiological history, past medical history, clinical manifestations, findings of laboratory tests, mNGS and imaging, diagnosis and treatment process and treatment outcome. Results All the 6 patients were males, aged 45-59 years. Four patients had a history of wild-fishing by the river many times, one had a history of fishing out the bird’s nests, and another one was living with sheep around his settlement before the disease onset. The onset occurred at any time throughout the year. The clinical manifestations were high fever in all patients (6/6), with remittent-fever being dominant (5/6). Other clinical pictures included weakness (6/6), chills (5/6), muscle pain (5/6), and poor appetite (4/6). Laboratory studies indicated decreased white blood cell (WBC) count in peripheral blood in 2 and decreased platelet count in 3 patients. Elevated levels of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase were seen in all the 6 patients, and increased creatine kinase was observed in 4. All patients had notably increased levels of C-reactive protein, procalcitonin, ferritin and D-dimer, and three had mildly escalated erythrocyte sedimentation rate. Pneumonia was free in the 6 patients by chest CT detection, and no endocarditis was seen in the 5 patients undergone echocardiography. Coxiella burnetii (Cb) was detected by mNGS in the 6 patients, who were confirmed as acute Q fever. All patients were recovered and discharged after medication with doxycycline (2 cases) or doxycycline combined with moxifloxacin (4 cases). Conclusion The clinical manifestations, imaging and laboratory test results of acute Q fever are unspecific, and the epidemiological history appears inconclusive in some patients. mNGS can contribute to quick and definitive diagnosis in the suspected patients, and doxycycline and moxifloxacin are effective in treatment of this infection.

Key words: Q fever, Metagenomics next-generation sequencing, Clinical features, Doxycycline