Horse Lyme Neuroborreliosis: Neurological Complications of Tick-Borne Disease

Lyme disease in horses can progress to neurological complications including neuroborreliosis, causing significant welfare challenges and requiring long-term treatment and management.

Key Facts

Lyme disease is caused by Borrelia burgdorferi, transmitted by Ixodes ticks in endemic regions of North America and Europe
Most horses exposed to Borrelia do not develop clinical disease, but a minority progress to significant illness
Neuroborreliosis involves infection of the nervous system, causing behavioral changes, sensory abnormalities, and gait problems
Diagnosis is challenging as serological tests indicate exposure but not active infection — PCR and clinical signs guide treatment
Treatment involves prolonged courses of antibiotics, typically doxycycline or intravenous oxytetracycline
Prevention focuses on tick control through regular checks, repellents, and appropriate pasture management

Welfare Considerations

Lyme neuroborreliosis in horses causes significant welfare compromise through neurological dysfunction that impairs normal movement, behavior, and perception. Affected horses may show hypersensitivity, difficulty moving, behavioral changes including aggression or depression, and muscle pain — all of which create ongoing suffering. The diagnostic challenge means horses may be undiagnosed or misdiagnosed for extended periods while the infection progresses. The prolonged antibiotic treatment required creates a management burden and horses may not recover completely even with appropriate treatment. Tick prevention is the most important welfare intervention — reducing tick burden through regular tick checks, appropriate repellents, and pasture management prevents the infection that leads to neuroborreliosis.

What You Can Do

Implement systematic tick checking for horses in endemic areas after outdoor activity
Use veterinarian-recommended tick repellents and acaricides for horses in high-risk regions
Seek veterinary evaluation promptly for horses showing neurological signs, behavioral changes, or gait abnormalities
Discuss Lyme disease testing for horses in endemic areas showing unexplained lameness or behavioral changes
Consider environmental tick management including targeted acaricide application in high-use areas
Support research into equine Lyme disease diagnosis and treatment to improve welfare outcomes