Autonomic Dysfunction in Patients with Acute Infection with Coxiella burnetii.
Milovanović, Branislav, Marković, Nikola, Ristanović, Elizabeta et al. · Pathogens (Basel, Switzerland) · 2025 · DOI
Quick Summary
This study looked at how the autonomic nervous system (the part that controls heart rate, blood pressure, and other automatic body functions) works in people who had acute infection with Coxiella burnetii, a bacterium that causes Q fever. Researchers tested 100 infected patients and 56 healthy controls using heart monitoring tests and found that infected patients had more problems with autonomic control, particularly in how their bodies regulate heart rate and blood pressure. These findings suggest that this infection might trigger lasting problems with the autonomic nervous system that could contribute to ME/CFS symptoms.
Why It Matters
ME/CFS patients and researchers have long suspected autonomic dysfunction as a key mechanism in post-infectious ME/CFS. This study provides objective physiological evidence that acute Coxiella burnetii infection can trigger measurable autonomic nervous system dysfunction, strengthening the biological plausibility of infection-triggered autonomic abnormalities in ME/CFS development. Understanding these mechanisms may guide future diagnostic approaches and therapeutic targets.
Observed Findings
Significantly higher prevalence of abnormal cardiovascular autonomic reflex test scores in the Coxiella group compared to controls
Reduced low-frequency power and baroreflex effectiveness index in infected patients, indicating parasympathetic regulation impairment
High rate of positive head-up tilt test findings with extreme blood pressure variability in the Coxiella group
Short-term heart rate variability indices consistently showed autonomic nervous system impairment in infected patients
No significant differences in long-term heart rate variability measures between groups
Autonomic dysfunction may contribute to development of ME/CFS and syncope in affected individuals following this infection
Short-term heart rate variability indices are more sensitive than long-term measures for detecting ANS impairment in this population
Remaining Questions
Does autonomic dysfunction persist long-term in patients who develop post-infectious ME/CFS versus those who recover?
What proportion of acutely infected patients with autonomic dysfunction subsequently develop ME/CFS?
What This Study Does Not Prove
This study does not prove that Coxiella burnetii infection directly causes ME/CFS, only that it is associated with autonomic dysfunction in some patients. The cross-sectional design cannot establish causation or determine whether autonomic dysfunction persists long-term or predicts ME/CFS development. The findings in acutely infected patients may not apply to all ME/CFS cases or other post-infectious conditions.