Emerging Q Fever Infection in Türkiye

Abstract

Objectives Q fever, caused by Coxiella burnetii, is an underrecognized zoonotic infection with diverse clinical manifestations. The nonspecific nature and slow progression of Q fever frequently delay diagnosis, sometimes leading to severe or even fatal outcomes. This study describes 32 patients diagnosed with Q fever over an 18‐month period in a previously unreported region, highlighting the emerging awareness of this neglected zoonosis. Methods Patients with seropositive C. burnetii Phase I/II IgM and/or IgG antibodies between October 2023 and March 2025 (18‐month period) were included. Cases were classified as acute, probable, chronic, or past infection according to established serological and clinical criteria. Results Thirty‐two patients were diagnosed during the study period, of whom 22 (68.8%) were male; the median age was 60.5 years (IQR: 48–66). More than half were farmers, and 40.6% reported animal exposure. Based on serological and clinical criteria, 11 patients were diagnosed with acute Q fever, 16 with probable infection, one with chronic infection, and four with past infection. Common manifestations included fever, myalgia, arthralgia, hepatitis, and endocarditis; cardiovascular involvement occurred in 40.6% of patients. Two patients died, and notably, three patients with prosthetic valve endocarditis had a history of care at the same cardiac surgery clinic. Conclusions Given its heterogeneous clinical manifestations and variable serological responses, Q fever poses significant diagnostic challenges. This study presents the first and largest human case series of Q fever from the Black Sea region of Türkiye, highlighting the wide clinical spectrum of the disease and the need for enhanced awareness and diagnostic capacity.