Lyme neuroborreliosis in 2 horses.
Authors: Imai D M, Barr B C, Daft B, Bertone J J, Feng S, Hodzic E, Johnston J M, Olsen K J, Barthold S W
Journal: Veterinary pathology
Summary
Lyme neuroborreliosis remains an under-recognised neurological manifestation of Borrelia burgdorferi infection in horses, presenting as a progressive chronic meningoradiculoneuritis with necrosuppurative inflammation affecting the spinal cord, nerve roots, and associated tissues. Using PCR amplification of multiple species-specific gene targets (ospA, ospC, flaB, dbpA, arp), researchers identified B burgdorferi sensu stricto in one case and demonstrated 99.9% genetic sequence identity to a human neuroborreliosis isolate, confirming that the same strain capable of causing severe neurological disease in people can establish infection in equine neurological tissue. Spirochetal burdens were highest in inflamed tissues including spinal cord, skeletal muscle, and joint capsules, with organisms predominantly localised within the dura mater and leptomeninges as visualised by Steiner silver staining and immunohistochemistry. For equine practitioners, this work highlights that progressive neurological signs—particularly those involving spinal cord dysfunction or atypical meningitis—warrant consideration of Borrelia burgdorferi as a differential diagnosis, particularly in endemic regions, and that cerebrospinal fluid analysis combined with serological and molecular testing may help distinguish Lyme neuroborreliosis from other causes of chronic spinal disease. Given the organism's tropism for neurological tissues and the documented ability to establish chronic infection, early recognition and appropriate antimicrobial treatment could alter the trajectory of what would otherwise be a progressive and potentially irreversible condition.
Read the full abstract on PubMed
Practical Takeaways
- •Lyme neuroborreliosis should be considered in horses presenting with progressive neurologic disease, particularly in endemic tick regions
- •The high similarity between equine and human Borrelia burgdorferi strains suggests horses may serve as sentinels for human Lyme disease risk in affected areas
- •Definitive diagnosis requires PCR and histopathology with specialized staining techniques; clinical suspicion is important in endemic regions
Key Findings
- •Lyme neuroborreliosis in horses presents as chronic necrosuppurative to nonsuppurative perivascular to diffuse meningoradiculoneuritis with progressive neurologic signs
- •Borrelia burgdorferi sensu stricto was identified via PCR with highest spirochetal burdens in spinal cord, muscle, and joint capsule tissues
- •Spirochetes were predominantly localized within the dura mater and leptomeninges, visualized by Steiner silver staining and immunohistochemistry
- •Equine B. burgdorferi isolate showed 99.9% sequence identity to human neuroborreliosis strain 297