Overview of Canine Aspergillosis
Aspergillosis is a fungal infection caused by a species of fungus belonging to the genus Aspergillus. The nasal cavity and respiratory system are most commonly affected, although in some dogs the infection may spread throughout the body with grave consequence.
Nasal aspergillosis is a localized form involving the nose, ears and paranasal sinuses and is usually caused by the fungus Aspergillus fumigatus. Disseminated aspergillosis is characterized by signs of generalized infection and is caused by the fungus Aspergillus tereus.
Dogs with medium or long noses are more likely to get nasal aspergillosis. Short nosed breeds such as pugs, bulldogs and Pekingese are less likely. Pre-existing nasal disease and/or prolonged antibiotic therapy predisposes to nasal infection. German shepherds are at higher risk for disseminated aspergillosis compared to other breeds. Diseases or conditions that suppress the immune system such as diabetes and chemotherapy also predispose to developing disseminated disease.
Dogs of any age are susceptible to nasal aspergillosis, but 40 percent of cases are seen in dogs younger than 3, and 80 percent in dogs younger than 7 years of age.
The impact of aspergillosis varies depending on whether it is confined to the nasal cavity only, or disseminated throughout the body. Many nasal infections are treated successfully, while most disseminated infections eventually prove fatal.
What to Watch For
Diagnosis of Aspergillosis in Dogs
Treatment of Aspergillosis in Dogs
Home Care and Prevention
No specific home care recommendations are necessary for dogs with nasal aspergillosis. Dogs with disseminated aspergillosis that are being treated for paralysis must be conscientiously managed. Physical therapy and cleanliness to prevent soiling and urine scalding are very important
There are no specific preventative measures against aspergillosis. There is no vaccine.
In-depth Information on Aspergillosis in Dogs
Aspergillus is a fungus that is ubiquitous in the environment. It generally causes either nasal or respiratory infections and disseminated infections. Nasal infections are not suspected to disseminate. The nasal infections tend to be caused by a different species of the fungus, namely Aspergillus fumigatus, compared to disseminated infections, which tend to be caused by Aspergillus tereus.
The immune status is an important determinant as to whether a dog will contract aspergillosis. Pre-existing nasal disease and/or previous prolonged antibiotic therapy may be important in the development of nasal infections. Conditions that suppress the immune system, such as diabetes, Cushing’s disease, chemotherapy, glucocorticoid therapy and hereditary immunosuppressive conditions may predispose dogs to developing disseminated aspergillosis.
Nasal aspergillosis is a relatively common disease in dogs. The disease usually remains confined to the nasal cavity or the sinuses, but marked destruction of the turbinates (delicate nasal bony structures) is always seen. Occasionally, a very invasive infection may affect the orbit (where the eyeball is located) and may even erode through the skull. Most cases of nasal aspergillosis are in dogs with normal immune systems that are in otherwise excellent health.
Nasal aspergillosis is usually seen in dolichocephalic (long-nosed) and mesocephalic (medium-nosed) breeds, but rarely in brachycephalic (short-nosed) breeds. Dogs of any age may be affected, but approximately 40 percent are 3 years old or younger, and 80 percent are 7 years of age or younger. The main features of the disease are a profuse nasal discharge consisting of blood mixed with pus, nasal pain, ulceration surrounding the nostrils, and nosebleed. Cancer of the nasal cavity can have very similar signs, and careful diagnostics are important so that the proper diagnosis can be made. Most cases of nasal aspergillosis can be successfully treated. Relapses are possible, but are uncommon.
Most cases of disseminated aspergillosis have occurred in German shepherd dogs aged 2 to 8 years. Aspergillus tereus is the most common species of organism responsible, although other species of Aspergillus have been isolated occasionally. It is thought that the fungus enters through the respiratory tract and goes to the lungs, then travels through the bloodstream where it spreads throughout the body. Infection often takes hold in the intervertebral discs of the spine, the eyes or the kidneys. Other organs, muscles or bones may be affected.
Disease tends to develop over several months, but most dogs are terminally ill when veterinary care is finally sought. The most consistent features of the disease are back pain progressing to partial or complete paralysis, or lameness of a limb with pronounced swelling and a discharging tract. A sudden onset of paralysis may result if an infected intervertebral disc ruptures and injures the spinal cord, or if the spine becomes unstable and dislocates. Other nonspecific findings include anorexia, weight loss, muscle wasting, fever, weakness, lethargy, vomiting, inflammation of the eye and lymph node enlargement. Severely ill dogs have a poor prognosis. Most dogs die from the disease although a few have been treated successfully.
In-depth Information on Diagnosis
In-depth Information on Therapy
Nasal aspergillosis is initially treated with antifungal drugs. They can be given orally, and they can be infused into the nasal cavity. Most cases are treated successfully, as evidenced by rapid resolution of nasal pain and nasal discharge, and healing of the ulcerated nostrils. Relapse is not a common problem, although bacterial infections of the nasal cavity can develop in up to 25 percent of dogs after the fungal infection is cleared. These bacterial infections usually respond well to antibiotics.
Disseminated aspergillosis has a poor prognosis, especially in dogs that are severely ill on presentation. Only two drugs have been shown to be effective in treating the disseminated disease.
Therapy for Nasal Aspergillosis in Dogs
Therapy for Disseminated Aspergillosis in Dogs
Follow-up Care for Dogs with Aspergillosis
Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not rapidly improve. Administer all prescribed medication as directed. Alert your veterinarian if you are experiencing problems treating your dog.
Return to your veterinarian for any follow up X-rays or blood tests necessary. Serum antibody levels may remain elevated for years after effective treatment, so this is not a good way to monitor the success of therapy.