Onchocercosis of an intervertebral joint capsule causing cervical vertebral stenotic myelopathy in a horse.

The study presents a unique case where the condition onchocercosis led to the development of nervous system disease, specifically cervical myelopathy, in a horse.

Background and Objective

• The study explores an unusual instance where a horse was affected by onchocercosis, a parasitic disease, which was identified as the cause for cervical myelopathy – a debilitating neurological condition in the animal.
• The main objective was to precisely diagnose and describe this unique case and improve our understanding of the effects of onchocercosis in horses.

The Case

• The research focuses on a 15-year-old Connemara mare that had to be euthanized because of progressing locomotive issues.
• A postmortem examination provided key insights into the animal’s condition. There was noticeable swelling in the soft-tissue of the C6-7 intervertebral joint capsule and a narrowing of the vertebral canal was also identified.

Findings

• Light microscopy was used for further analysis of the situation. It revealed axonopathy – a disorder affecting nerve axons – in the spinal cord segment which corresponded to the part of the joint capsule that was affected.
• Tissue examination showed the presence of fibrous tissue and eosinophilic granulomas, immune cells associated with parasitic infections, in the joint capsule.
• The parasites involved in the infection were identified as belonging to the Onchocerca species, linking the conditions of the horse to onchocercosis.

Conclusions

• This unique case forms a crucial link between onchocercosis and cervical myelopathy in horses, expanding our knowledge about the potential effects diseases can have on an animal’s nervous system.
• Further research may be necessary to uncover similar cases, and to deepen understanding about the interaction between parasitic infections and neurological health in horses and potentially other animals.