# Autonomic Dysfunction in Patients with Acute Infection with Coxiella burnetii

## TL;DR

This study finds that infection with Coxiella burnetii is linked to autonomic nervous system dysfunction, which may contribute to ME/CFS and syncope.

## Contribution

The study provides evidence that Coxiella burnetii infection may lead to persistent autonomic dysfunction, potentially linking it to ME/CFS.

## Key findings

- Coxiella-infected patients showed higher autonomic dysfunction, mainly affecting parasympathetic regulation.
- Abnormal cardiovascular reflex test scores and reduced baroreflex effectiveness were observed in infected individuals.
- Head-up tilt testing revealed extreme blood pressure variability in Coxiella-positive patients.

## Abstract

Background: Coxiella burnetii 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 Coxiella burnetii. Methods: 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 Coxiella group, head-up tilt testing (HUTT). Results: A significantly higher prevalence of autonomic dysfunction was observed in the Coxiella 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. Conclusions: These findings suggest that Coxiella burnetii 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.