Aspergillosis in Donkeys: Fungal Respiratory Infection and Sinus Disease

Aspergillosis is a fungal infection caused by Aspergillus species, molds that are common in hay, bedding, feed, soil, and barn air. In donkeys and other equids, the disease is usually a respiratory or sinus problem, not a skin problem. The fungus may affect the nasal passages, paranasal sinuses, lungs, or the guttural pouch, a paired air-filled structure near the throat that is unique to equids.

In practice, many donkey cases are managed using what is known from horses because published donkey-specific data are limited. The most urgent form is guttural pouch mycosis, where fungal plaques develop near important arteries and cranial nerves. That can lead to sudden nosebleeds, trouble swallowing, or neurologic changes. Sinonasal disease may look less dramatic at first, but it can still cause chronic discharge, facial discomfort, and poor performance.

This is not something a pet parent can confirm at home. Fungal disease can look like bacterial sinusitis, dental root disease, foreign bodies, masses, or trauma. Your vet will need to sort through those possibilities and help you choose a care plan that fits your donkey's condition and your goals.

The fungus itself is usually not rare. Aspergillus spores are widespread in the environment and are commonly found in hay, straw, grain, dust, composting organic matter, and damp barn areas. Most healthy equids inhale these spores without becoming sick. Disease tends to happen when spores settle in a favorable area, such as damaged tissue in the nasal passages, sinuses, lungs, or guttural pouch.

Several factors may raise risk. These include poor-quality or moldy forage, dusty housing, poor ventilation, chronic respiratory irritation, and underlying disease that weakens normal defenses. In horses, Merck notes that pulmonary or more invasive aspergillosis may be associated with intestinal inflammation or other problems that affect immune function. Long-term corticosteroid use, severe illness, or prolonged antibiotic exposure may also make fungal infection more likely in some animals.

Not every donkey with fungal disease has an obvious trigger. Sometimes the main issue is local anatomy and tissue damage rather than whole-body illness. That is one reason your vet may recommend looking for dental disease, sinus blockage, previous upper airway problems, or signs of aspiration and swallowing dysfunction.

Diagnosis starts with a careful physical exam and a clear history. Your vet will want to know whether the discharge is one-sided or two-sided, whether there has been any bleeding, and whether your donkey is having trouble eating, swallowing, or breathing. In equids, endoscopy is often one of the most useful next steps because it can directly show fungal plaques in the guttural pouch or abnormalities in the upper airway.

For sinus or nasal disease, your vet may recommend skull radiographs or CT, along with endoscopy of the nasal passages and sample collection. Samples may be sent for cytology, fungal culture, histopathology, or PCR, depending on what tissue is available and what your vet is trying to rule out. Imaging helps define how extensive the disease is, but it usually cannot confirm fungal infection by itself.

If lower airway or lung involvement is suspected, additional testing may include ultrasound, radiographs, transtracheal wash, bronchoalveolar lavage, or bloodwork. Because fungal disease can mimic bacterial infection, tumors, dental root disease, and foreign bodies, diagnosis often relies on a combination of imaging, endoscopy, and laboratory testing rather than one single test.

You cannot remove Aspergillus from the environment completely, but you can lower exposure and support your donkey's normal airway defenses. Start with clean, dry forage and bedding. Avoid feeding visibly moldy hay or grain, improve barn ventilation, reduce dust, and store feed where moisture cannot build up. If your donkey is sensitive to dusty hay, ask your vet whether soaking or steaming forage is appropriate for your setup.

Good general health care matters too. Prompt attention to chronic nasal discharge, dental disease, swallowing problems, and recurrent respiratory irritation may reduce the chance that fungal organisms gain a foothold. Keep water sources clean, remove spoiled organic material from feeding areas, and avoid prolonged exposure to damp, poorly ventilated spaces.

There is no vaccine for aspergillosis in donkeys. Prevention is really about environment, early detection, and follow-up. If your donkey has had previous sinus or guttural pouch disease, ask your vet what kind of recheck schedule makes sense, especially if any discharge, odor, coughing, or bleeding returns.