Polysynovitis in a horse due to Borrelia burgdorferi sensu lato infection–Case study.

This study reports the first confirmed case of Lyme borreliosis causing joint inflammation in a horse in Italy. The research highlights a potential biological risk for humans sharing the same environment with horses, as the disease is similarly transmitted in both species.

Overview

Researchers discuss a clinical case of Lyme borreliosis (LB), caused by Borrelia burgdorferi, yielding to polysynovitis in a horse. Despite high seroprevalence being reported in European horses, there have been no clinical cases documented until this one. This finding sheds light on the potential risk for humans as horses and humans share a similar habitat and the disease transmission pathway is similar in both species.

Patient Description and Symptoms

• The subject of the study was a 6-year-old Paint gelding horse with a three-week history of fever, intermittent lameness, and effusion of the right hind limb’s digital flexor tendon sheath.

Case Investigation and Diagnosis

• The horse underwent a rigorous diagnostic protocol which incorporated serological tests for infectious diseases and molecular studies.
• The resulting diagnosis was polysynovitis due to an infection by B. burgdorferi.
• Interestingly, the pathogen’s DNA could not be found in two of the affected joints. This absence is a previously unreported aspect in the clinical cases involving horses.

Implication of the Findings

• This is the first documented clinical case of equine Lyme borreliosis in Italy, contributing to the scant literature on the manifestation of this disease in horses.
• This study suggests a potential similarity with human cases, where the joint disease caused by B. burgdorferi has been linked to an immune-mediated response, yet the pathogen’s DNA could not always be detected in the affected joints.
• The similarities between human and equine transmission of the disease, coupled with their shared habitats, support the proposition of using horses as a sentinel species to indicate human biological risk in areas where Lyme borreliosis is prevalent.