Aspergillosis in Dogs

Aspergillosis is a particular type of fungal infection that is caused by various species of Aspergillus, an organism that is common worldwide. The symptoms your dog exhibits will dependent on the type of severity of the infection, ranging from abundant nasal discharge to general lethargy. Aspergillus can cause considerable damage if left untreated and should be combated with antifungal medication as soon as possible for a better prognosis.

Signs of aspergillosis include:

• Greenish-yellow nasal discharge
• Ulcers around the nostrils
• Pain or discomfort around the face (especially nasal cavity)
• Sneezing
• Lethargy
• Lack of pigment or tissue on the surface of the skin
• Bleeding around the nose or nostrils

Additional symptoms may be exhibited with disseminated aspergillosis though they vary depending on where the disease has spread. These include non-specific signs such as weight loss and lameness.

Types

• Nasal aspergillosis - the more common form of the disease and affects the nasal passages, leading to mucus discharge and other signs of infection around the nose.
• Disseminated aspergillosis - which is rarer, may occur in various areas of the body, including lymph nodes, stomach, kidneys, and vertebrae.

Aspergillosis is caused by the Aspergillus fungi, which is an organism that is commonly found throughout the world in compost piles, barns, and stables. Aspergillus fungi was first discovered in the environment in 1729 and it's first case associated with family (companion) animals was in 1829. The infection is typically limited to the nasal cavities and is often caused by Aspergillus fumigates, but there is a small chance that it may spread to other areas of the body and involve other species of the fungus. The disseminated disease is identified primarily in female German shepherd dogs, while the nasal infection affects dogs with long noses, such as collies. Dogs with weakened immune systems, any type of underlying lung disease, and chronic or severe asthma are more at risk for aspergillosis.

The symptoms for aspergillosis can be non-specific, especially with the disseminated disease. If you notice that your dog has nasal discharge or is behaving abnormally, visit the veterinarian, and provide a list of symptoms and their duration. The veterinarian will take your dog’s history and conduct a physical examination, which may include a blood test or a urinalysis as part of the initial diagnostics process.

With nasal aspergillosis, a diagnosis can be made by examining nasal discharge and identifying the organisms responsible for the infection. This is not reliable, however, as Aspergillus is commonly found and may be present even in animals whose symptoms are not related to aspergillosis. Instead, the veterinarian may recommend radiographs, which will reveal any damage the fungus may have caused in your dog’s nasal tissues. Another diagnostic tool is a rhinoscopy, which gives the veterinarian a clear image of the nasal cavity and helps with performing a biopsy if needed.

Diagnosis for disseminated aspergillosis varies according to the affected area, but tests may include x-rays, CT, and urinalysis.

Antifungal medication is most commonly the preferred treatment of choice for aspergillosis. Oral drugs, such as itraconazole, are available but do not have a consistent rate for success. These systemic drugs also carry side effects that your dog may not tolerate well but is necessary for dogs with the disseminated disease.

Topical antifungal medication tends to have a higher rate of success than systemic drugs and is recommended for dogs with nasal aspergillosis. Using general anesthesia, this treatment involves applying the solution directly into the nose, where it is left for up to an hour. During this time, your dog will regularly be turned in order to maximize contact with the antifungal medication. Before your dog wakes up, excess medication will be drained out through the nostrils.

The success rate of the treatment depends on how widely the infection has spread, the extent of the damage, and the general spread of the fungus. Treatment is considered effective for dogs where the infection is confined to the nasal cavity, but if the infection is systemic or has entered the brain, the success rate is lower.

In some cases, several approaches to treatment may be required in order to fully clear out the infection. In the case of severe infections, your dog may need to be hospitalized so that the veterinarian can complete treatment.

Once your dog is home again, monitor it for nasal discharge, and inform the veterinarian if you notice any additional symptoms. The veterinarian will usually ask, and prefer, for you to bring your dog back for follow-up examinations to ensure that the infection has been cleared out.