Autonomic Dysfunction in Patients with Acute Infection with Coxiella burnetii

<b>Background:</b><i>Coxiella burnetii</i> is a common zoonotic pathogen that can lead not only to acute or chronic Q fever but also to post-infectious syndromes, where autonomic nervous system (ANS) dysfunction has been suggested as a contributing mechanism. This study aimed to assess autonomic function in patients presenting with polymorphic symptoms, dysautonomia, or ME/CFS who had serological evidence of acute infection with <i>Coxiella</i> burnetii. <b>Methods:</b> A total of 156 participants were evaluated, including 100 seropositive patients and 56 matched controls. All subjects underwent standardized cardiovascular reflex tests (CART), beat-to-beat analysis of heart rate and blood pressure with baroreflex indices, 24 h Holter ECG with HRV assessment, and, in the <i>Coxiella</i> group, head-up tilt testing (HUTT). <b>Results:</b> A significantly higher prevalence of autonomic dysfunction was observed in the <i>Coxiella</i> group, predominantly affecting parasympathetic regulation, with abnormal CART scores, reduced LF power and baroreflex effectiveness, and a high rate of positive HUTT findings characterized by extreme blood pressure variability. Although long-term HRV measures did not differ significantly between groups, short-term indices consistently indicated ANS impairment. <b>Conclusions:</b> These findings suggest that <i>Coxiella burnetii</i> infection may trigger persistent autonomic dysfunction, potentially contributing to the development of ME/CFS and syncope in affected individuals. Further longitudinal studies are needed to clarify pathophysiological mechanisms and clinical implications.