Hirudotherapy as an Adjunct Treatment for Refractory Corneal Ulcers in Dogs and Cats: First Clinical Report

Abstract

Corneal ulcers remain a therapeutic challenge in veterinary ophthalmology, particularly when chronic or refractory to conventional medical management. Hirudotherapy, widely used in human and veterinary medicine for its vasodilatory, anticoagulant, and anti-inflammatory properties, has not previously been described in the management of corneal ulcers in animals. This report describes the first documented clinical application of medicinal leeches (Hirudo spp.) applied to the conjunctiva and sclera as an adjunctive treatment for refractory corneal ulcers in dogs and cats. A rapid resolution of a chronic canine corneal ulcer was observed following a single hirudotherapy session, with complete epithelial healing within 3.5 days. These preliminary findings suggest that hirudotherapy may enhance periocular microcirculation and support corneal healing. Further controlled studies are warranted.

Introduction

Chronic corneal ulcers represent a significant therapeutic challenge in small animal ophthalmology.

When standard medical and surgical approaches fail or are unavailable, alternative methods may offer valuable adjunctive support. Hirudotherapy involves the controlled application of medicinal leeches, whose saliva contains biologically active substances such as hirudin, antithrombin, vasodilators, and anti-inflammatory compounds. These effects may improve local blood flow and tissue repair. To the author’s knowledge, this is the first clinical report describing the use of hirudotherapy in veterinary ophthalmology for corneal ulcer management.

Materials and Methods

Type and origin of leeches:

The leeches used were Hirudo troctina (commonly called "the dragon"), collected from a lake in Tamda, near Tizi-Ouzou, where the study was conducted.

Preparation and precautions:

Leeches must not be stressed during therapy to prevent regurgitation, which can be a source of infection.

Prophylactic antibiotic therapy is recommended after each session in stressful environments. The main pathogen involved is Aeromonas spp., particularly Aeromonas hydrophila, present in the leech gut.

Correct identification of the head and tail of the leech is essential to ensure proper attachment to the treatment site.

Application method:

The leech is placed in the barrel of a 2 mL syringe, which is applied against the bulbar conjunctiva. Alternatively, it can be held on a moistened compress after identifying its head, directed toward the target area.

Avoid antiseptics such as diluted povidone-iodine or other products, as leeches will not bite on surfaces with an unpleasant taste. Clean the area with water only, rinsing several times if necessary.

Most dogs remain calm without anesthesia, though sedation may be required for fearful or aggressive animals. The leech releases a local anesthetic substance, allowing the dog to feel no pain during therapy.

Once attached (approximately 3–5 minutes), the leech feeds to satiation, usually for 30–45 minutes, then detaches spontaneously. Minor post-treatment bleeding can be controlled by compression with a compress, gently closing the eye for a short period.

Post-treatment disposal:

After therapy, leeches are placed in a container with 90% alcohol, where they die instantly, ensuring safe and hygienic disposal.

Case Description

A 2-year-old Rottweiler presented with a chronic corneal ulcer persisting for over five months, associated with severe corneal edema and proximity to a descemetocele. Initial medical therapy resulted in partial improvement. The ulcer was subsequently debrided, and a medicinal leech was applied to the conjunctiva. A temporary third eyelid flap was placed to protect the cornea while allowing topical antibiotic administration. Complete corneal epithelialization was observed within 3.5 days, leaving only a mild leucoma related to underlying entropion, which was surgically corrected.

Discussion

The rapid healing observed may be attributed to enhanced periocular vascularization and improved delivery of healing factors to the cornea. Hirudotherapy could represent a low-cost, accessible adjunctive treatment for refractory corneal ulcers, particularly in regions with limited surgical resources. Limitations include infection risk and the need for proper leech sourcing and antibiotic prophylaxis.

Conclusion

This first documented clinical use of hirudotherapy for corneal ulcer treatment in veterinary medicine suggests a potential role as an adjunctive therapy. Larger case series and controlled studies are required to confirm efficacy and safety.