Brazilian Lyme-Like Syndrome: Why It Remains a Clinical Concern

Brazilian Lyme-like syndrome (BYS) continues to challenge clinicians, with growing evidence supporting a true Borrelia infection.

Recent polymerase chain reaction (PCR) testing has confirmed the presence of Borrelia burgdorferi sensu stricto in Brazil, strengthening the case that this condition represents a borrelial infection rather than a distinct syndrome, writes Miziara.

Unlike Lyme disease in North America and Europe, which is transmitted by Ixodes ticks, BYS appears to involve Amblyomma and Rhipicephalus species.

Despite geographic and vector differences, the clinical and biologic overlap with Lyme disease is substantial.

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Clinical Manifestations

• Erythema migrans rash in approximately 50% of cases
• Neurologic involvement: meningitis, cranial neuritis, peripheral neuropathy
• Psychiatric symptoms in ~20% of patients
• Ocular involvement: diplopia, uveitis, optic nerve damage
• Arthritis of large joints (30–35%)
• Cardiac conduction abnormalities

Severe complications such as encephalitis and chronic neurologic disease have also been reported.

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Microbiologic Findings

Studies have demonstrated multiple morphologic forms of Borrelia burgdorferi, including cystic and cell-wall–deficient forms.

PCR testing has detected B. burgdorferi DNA months to years after infection—even following antibiotic treatment—raising concerns about persistence.

Evidence also suggests activation of the neuro-immune-endocrine axis, potentially driven by ongoing immune stimulation.

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Diagnostic Challenges

• Diagnosis is difficult without a rash
• Serologic testing alone is insufficient
• Symptoms overlap with chronic fatigue syndrome and autoimmune disease
• Symptoms often wax and wane over time

The authors question how many patients diagnosed with chronic fatigue syndrome or autoimmune disease may instead have unrecognized Borrelia infection.

Learn more about Lyme disease testing challenges and why diagnosis can be difficult.

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Treatment Considerations

• Early-stage disease may respond to short-course antibiotics
• Delays beyond 3 months are associated with recurrence in ~75% of cases
• Disseminated disease often requires longer treatment
• Neuroborreliosis may require IV antibiotics followed by oral therapy

Delayed diagnosis increases the risk of chronic neurologic and rheumatologic complications.

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Autoimmune Overlap

BYS may trigger autoimmune-like manifestations, including:

• Arthritis
• Raynaud’s phenomenon
• Lupus-like skin lesions
• Scleroderma-like features
• Sicca symptoms and myositis

This overlap further complicates diagnosis and treatment decisions.

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Clinical Perspective

This syndrome highlights broader challenges seen in Lyme disease worldwide—diagnostic uncertainty, overlapping syndromes, and the possibility of persistent infection.

In my experience, clinicians should remain open to infectious causes when evaluating chronic, multisystem illness—particularly when symptoms are unexplained or relapsing.

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Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention