Fungal Keratitis in Donkeys
- See your vet immediately. Fungal keratitis is a painful corneal infection that can worsen fast and may threaten vision within days.
- Common warning signs include squinting, tearing, a cloudy or white spot on the eye, corneal haze, discharge, and sensitivity to light.
- In donkeys, trauma from hay, grass awns, dust, or other plant material can damage the cornea and give environmental fungi a chance to invade.
- Diagnosis usually involves a fluorescein stain, close eye exam, corneal cytology, and often fungal culture. Some referral centers also use confocal microscopy.
- Treatment often requires frequent medicated eye drops, pain control, and close rechecks. Deep or melting ulcers may need referral surgery to save the eye.
What Is Fungal Keratitis in Donkeys?
Fungal keratitis is a fungal infection of the cornea, the clear front surface of the eye. In equids, this condition is often called keratomycosis. It usually starts after the cornea is scratched or ulcerated, then fungi from the environment invade the damaged tissue. Because donkeys live around hay, bedding, soil, and plant material, their eyes are regularly exposed to fungal spores.
This is not a minor eye irritation. Fungal corneal infections can become deep, painful, and destructive, especially if the ulcer is already severe or if the cornea begins to "melt" from inflammation. In equine patients, Aspergillus and Fusarium are among the most commonly reported fungal organisms in corneal disease, and the same general principles are used when caring for donkeys.
Early treatment matters. A donkey may start with tearing and squinting, then progress to a cloudy cornea, a white or yellow plaque, worsening pain, and even rupture of the eye if care is delayed. With prompt treatment and close follow-up from your vet, some eyes heal well, but severe cases can leave scarring or permanent vision loss.
Symptoms of Fungal Keratitis in Donkeys
- Squinting or holding the eye closed
- Excess tearing
- Cloudy, blue, white, or gray cornea
- White, yellow, or tan plaque or spot on the cornea
- Eye discharge
- Light sensitivity
- Redness around the eye
- Visible corneal ulcer or surface defect
- Swollen eyelids or rubbing at the eye
- Small pupil or signs of uveitis
Any painful eye in a donkey is urgent, and a cloudy eye with squinting should be treated as an emergency. Fungal keratitis can look similar to other corneal problems at first, but it may progress quickly and become much harder to manage once the infection is deep.
Call your vet the same day if you notice squinting, a white spot, corneal cloudiness, or discharge. If the eye suddenly looks more swollen, the cornea appears to bulge, or your donkey seems much more painful, seek emergency care right away.
What Causes Fungal Keratitis in Donkeys?
Fungal keratitis usually develops when the cornea is first damaged, then contaminated by fungi from the environment. In donkeys, common triggers include scratches from hay stems, grass awns, dust, windblown debris, or a foreign body trapped under the eyelid. Trauma is especially important in equids because corneal wounds are common and environmental fungi are everywhere.
The fungi involved are often normal environmental organisms rather than something "caught" from another animal. In horses, Aspergillus and Fusarium are reported most often, with other molds and yeasts seen less commonly. A damaged cornea gives these organisms a place to attach and grow.
Some factors can raise risk further. Delayed treatment of a corneal ulcer, prolonged use of topical corticosteroids, heavy organic contamination, and warm or humid conditions may all make fungal infection more likely. Secondary bacterial infection can also complicate the picture and increase tissue damage.
Because donkeys can be stoic, they may not show dramatic pain early on. That can make a small injury look less serious than it is, which is one reason prompt eye exams matter so much.
How Is Fungal Keratitis in Donkeys Diagnosed?
Your vet will start with a careful eye exam. This usually includes checking for pain, discharge, corneal cloudiness, pupil changes, and signs of uveitis. A fluorescein stain is commonly used to look for an ulcer or corneal defect, and magnification helps assess how deep and extensive the lesion is.
To identify infection, your vet may collect a corneal cytology sample from the ulcer or plaque. Cytology can sometimes show fungal hyphae quickly, which helps guide early treatment. A fungal culture may also be recommended, especially in deeper, nonhealing, or severe cases, although culture results can take days. In referral settings, in vivo confocal microscopy may help detect fungal elements in the cornea without taking as much tissue.
Your vet may also look for secondary bacterial infection and assess whether the cornea is melting or at risk of perforation. If the ulcer is deep, painful, or not responding as expected, referral to a veterinary ophthalmologist is often the safest next step.
Diagnosis is not only about naming the organism. It also helps your vet judge how aggressive treatment needs to be, whether surgery should be considered, and what the likely outlook is for comfort and vision.
Treatment Options for Fungal Keratitis in Donkeys
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Urgent farm or clinic exam with fluorescein stain
- Corneal cytology when feasible
- Topical antifungal medication such as natamycin, miconazole, or compounded voriconazole based on your vet's plan
- Pain control and anti-inflammatory support chosen by your vet
- Protective management, reduced dust exposure, and strict medication schedule
- Short-interval rechecks
Recommended Standard Treatment
- Full ophthalmic exam and repeat fluorescein staining
- Corneal cytology plus fungal culture or additional diagnostics
- Targeted topical antifungal therapy, often with multiple medications
- Medication plan for pain, uveitis, and secondary bacterial infection when indicated
- Possible subpalpebral lavage system placement to make frequent eye treatment safer and more realistic
- Serial rechecks to track ulcer depth, fungal response, and corneal stability
Advanced / Critical Care
- Referral ophthalmology care
- Advanced imaging or confocal microscopy when available
- Intensive medical therapy with frequent topical treatment and hospitalization when needed
- Surgical procedures such as superficial keratectomy, conjunctival grafting, or other corneal support procedures for deep, melting, or nonhealing ulcers
- Management of severe uveitis, stromal abscessation, or impending perforation
- Extended aftercare and repeat specialty rechecks
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Fungal Keratitis in Donkeys
Bring these questions to your vet appointment to get the most out of your visit.
- Does this look like a superficial ulcer, a deep ulcer, or a stromal abscess?
- Did you see signs that make fungal infection more likely than a bacterial ulcer alone?
- Should we do corneal cytology, fungal culture, or referral diagnostics now?
- Which medications are most important, and how often do they need to be given?
- Would a subpalpebral lavage system help us treat this eye more safely and consistently?
- What warning signs mean the ulcer is worsening or the eye could perforate?
- What level of vision do you think is realistic to preserve in this case?
- If this does not improve quickly, when should we consider referral surgery?
How to Prevent Fungal Keratitis in Donkeys
Not every case can be prevented, but reducing corneal injury is the best place to start. Check your donkey's eyes regularly, especially during dusty weather, after turnout in rough forage, or if there has been recent hay, bedding, or trailer-related eye irritation. Remove obvious environmental hazards when possible, and ask your vet to examine any eye that looks teary, cloudy, or painful.
Prompt treatment of any corneal ulcer matters. A small scratch can become infected with fungi after exposure to plant material and dust. Early veterinary care may lower the chance that a simple ulcer turns into a deep fungal infection.
Use eye medications only under your vet's guidance. Topical corticosteroids can worsen some corneal infections and may increase the risk of fungal involvement when an ulcer is present. If your donkey has a history of eye disease, ask your vet which medications are safe to keep on hand and which should never be started without an exam.
Good barn and pasture management also helps. Limiting heavy dust, storing hay to reduce mold exposure, and addressing sharp feeders or protruding wire can reduce eye trauma risk. Prevention is not about creating a perfect environment. It is about catching small problems early and giving the cornea the best chance to heal before fungi take hold.