First reported case of Parafilaria bovicola infection in a horse (Equus caballus).

Overview

• This study documents the first known case of Parafilaria bovicola infection in a horse.
• The research details the observation, diagnosis, surgical treatment, and molecular identification of the nematode causing the infection.

Introduction to Parafilaria bovicola and Host Range

• Parafilaria bovicola is a nematode parasite typically associated with cattle.
• It causes nodular subcutaneous infections commonly known as parafilariosis.
• The usual hosts are bovines, but this study reports an unusual accidental infection in a horse (Equus caballus).
• Such cross-species infections are rare and represent a new veterinary concern in enzootic areas where this parasite is present.

Clinical Presentation and Diagnosis

• The horse presented with a soft, non-painful, fluctuated subcutaneous nodule located beneath the right eye.
• Ultrasound imaging was performed, revealing a fluid-filled cyst containing a mobile worm-like structure.
• The presence of a motile parasite within the lesion strongly suggested an active parasitic infection rather than other causes such as cysts or tumors.

Surgical Intervention and Identification

• A surgical procedure was undertaken to extract the nematode from the cystic lesion.
• The physical removal allowed detailed examination and facilitated molecular analysis.
• Molecular diagnostics involved sequencing the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, a commonly used genetic marker for species identification in nematodes.
• Sequencing confirmed that the parasite was indeed Parafilaria bovicola, establishing the diagnosis unequivocally.

Significance of Findings

• This is the first documented case of Parafilaria bovicola infecting a horse, expanding the known host range of this parasite.
• The finding suggests that horses living in areas where P. bovicola is endemic may act as accidental hosts.
• Veterinarians should consider parafilariosis in differential diagnosis when encountering similar subcutaneous nodules in horses from enzootic regions.
• Understanding cross-species infections helps improve diagnosis, treatment, and epidemiological surveillance of parasitic diseases.

Implications for Veterinary Practice and Future Research

• Veterinarians should be aware of the potential for P. bovicola infection in species other than cattle, especially in enzootic regions.
• Early diagnosis through imaging and molecular methods is crucial to managing the infection effectively.
• Surgical extraction can serve as both a therapeutic and diagnostic tool.
• Further research is needed to assess the prevalence of P. bovicola in horses and to understand the potential clinical impact in accidental hosts.