Chronic Lyme Disease: An Evidence-Based Definition by the ILADS Working Group

Area of Science:

• Infectious Diseases
• Rheumatology
• Neurology

Background:

• Chronic Lyme disease (CLD) has been poorly defined and often dismissed.
• A clear, evidence-based definition is needed to advance understanding and research.

Purpose of the Study:

• To provide an evidence-based definition for chronic Lyme disease (CLD).
• To characterize the clinical spectrum of CLD in untreated and previously treated patients.

Main Methods:

• Systematic review of over 250 peer-reviewed papers.
• Analysis of international literature on CLD manifestations.

Main Results:

• CLD is defined as a multisystem illness with symptoms present for at least six months, resulting from active Borrelia burgdorferi sensu lato (Bbsl) infection.
• Two subcategories were identified: CLD, untreated (CLD-U) and CLD, previously treated (CLD-PT).
• The literature review validated that chronic Bbsl infections can lead to chronic disease.

Conclusions:

• The proposed CLD definition clarifies the term and its clinical implications.
• This definition facilitates a better understanding of Lyme disease and promotes future research.