Lyme Disease in Horses: Detection, Treatment, and Welfare Management

Lyme disease caused by Borrelia burgdorferi affects horses in tick-endemic regions, causing vague but debilitating symptoms that are frequently misdiagnosed, leading to prolonged unnecessary suffering.

Key Facts

Horses in tick-endemic regions of Northeast US have 50-75% seropositivity rates
Most seropositive horses never develop clinical disease, having cleared the infection
Clinical Lyme in horses causes lameness, behavioral changes, muscle soreness, and lethargy
Neurological Lyme (Neuroborreliosis) is a rare but severe manifestation
Diagnosis is complicated by the lack of a definitive test for active infection
Treatment involves 4-8 weeks of doxycycline or minocycline antibiotic therapy
A licensed Lyme vaccine for horses exists and is recommended in endemic areas

Welfare Considerations

Horses with clinical Lyme disease often present with vague, shifting symptoms that make diagnosis challenging. These horses may suffer for extended periods while owners and vets investigate other potential causes. The behavioral changes associated with Lyme - irritability, sensitivity, resistance to work - are frequently misinterpreted as training problems, leading to potentially aversive training responses rather than medical care. The welfare imperative is clear: horses in tick-endemic areas with unexplained lameness, behavior change, or muscle pain should be promptly evaluated for Lyme disease.

What You Can Do

Apply tick prevention products approved for horses in endemic regions
Conduct daily tick checks, focusing on mane, tail, and under-saddle areas
Vaccinate horses in Lyme-endemic areas annually before tick season
Keep pastures mowed and reduce brush at field margins to minimize tick habitat
If Lyme is suspected, request a Lyme multiplex assay (C6 antibody test)
Monitor treated horses closely and complete full antibiotic course