Fungal Infection (Blastomycosis) in Dogs

Blastomycosis in dogs is a fungal disease that begins its infection in the lungs and then spreads to other bodily tissues. This infection is caused by the Blastomyces dermatitidis, which is commonly found in moist soil and within decomposing wood and leaves. It can also be found in animal waste in a moist environment.  This fungus is found in North America and is more prevalent in Mississippi, the Ohio River Valley, Missouri, and the Mid-Atlantic states. It is also found in Canada; it is known to be in Manitoba, Quebec, Ontario, and Saskatchewan.

Once spores enter the body through inhalation, yeast is formed that infects the lungs and begins to spread to other tissues. It is spread through the lymphatic system or through the bloodstream.

Blastomycosis in dogs is caused by a fungus, Blastomyces dermatitidis, which is commonly found in moist areas of soil, leaves, and wood. The infection begins in the lungs and spreads to other parts of the body.

If your dog becomes infected with the fungus Blastomyces dermatitis, he will exhibit specific symptoms that will warrant a trip to the veterinarian. Symptoms of blastomycosis may vary depending on the severity of the disease, and where the disease is located or has spread. Symptoms can include:

• Weight loss
• Loss of appetite
• Lethargy
• High fever
• Cough
• Respiratory distress
• Enlarged lymph nodes
• Eye lesions
• Conjunctivitis, or red eye
• Discharge from the eye
• Ulcers on the skin
• Skin lesions
• Neck pain
• Circling
• Confusion

Types

This infection begins in the lungs, but if left untreated can spread to other parts of the body. The lung lesions can heal if treated early, thus not allowing the fungal infection to spread. Making an appointment with the veterinarian as soon as your dog shows clinical signs is important to diagnose and treat the infection as early as possible. Types of areas this infection can spread to include:

• Eyes
• Bones
• Skin
• Lymph Nodes
• Other tissues, which is less common

Causes of blastomycosis are mostly relative to the environment in which the dog is being raised. Sporting and hunting dogs that are ages two to four years old are shown to be more affected. Causes include:

• Exposure to soil with Blastomyces dermatitidis
• Exposure to moss and wooded areas with Blastomyces dermatitidis
• Exposure to moist areas with this type of fungus
• The inhalation of the Blastomyces dermatitidis

If you suspect your dog has a fungal infection, or is exhibiting the symptoms above, be sure to call your veterinarian and make an appointment. The veterinarian will ask about the dog’s history and may also ask what type of environment he is in when outside, to give her a clue as to any type of fungus that he could be infected with.

The veterinarian will want to take a complete blood count and biochemistry profile to check for any infections or other abnormalities. If the veterinarian suspects this type of fungal infection, then she will perform a thoracic imaging test, to get a closer look at your companion’s lungs. The infection may also be revealed in cytologic testing by the collection of samples of tissue and further studying of the cells within the tissue.

The medical professional may also perform other testing, such as urinary antigen testing, polymerase chain reaction examinations, and serologic testing. It will be important that the veterinarian runs several different types of test to be sure she gets an accurate diagnosis of blastomycosis. If your veterinarian suspects that the fungus has spread to other body tissues, she will order even more tests that are specific to the area of the body that may be affected. She may run tests on any skin lesions your dog may have, test the ocular areas, perform a radiograph of the bones, or biopsy any suspected tissue.

The main method of treatment for this fungal infection is the use of antifungal medications. There is a wide variety of fungal-fighting drugs, and your veterinarian will prescribe the one (or more than one) which will work the best to kill any fungus that is infecting your loved one.

Once your dog begins taking the medication prescribed by your veterinarian, and if the fungal infection is caught in the early stages (before it has spread and become very severe), your loved one may begin to feel better before you know it. Prognosis is good if this is caught early.

Your veterinarian will give you updates on prognosis, and all of this depends on your dog, the severity of his blastomycosis, and how his body is responding to the treatments. Be sure to give your dog the needed medication until it is finished. In terms of exercise, it is important to limit your dog’s play and running in order to allow the lungs to heal, and your veterinarian may prescribe or recommend a change in diet to keep him as stimulated as possible in terms of appetite.

This condition may be prevented by keeping your dog way from the environments that house this type of fungus. It is very difficult to avoid Blastomyces dermatitidis, especially if you live in an area that is at risk for contamination and if your dog is an outdoor sporting or working dog. Knowing the clinical signs will keep you proactive in finding quick treatment if your dog is to become infected. If your dog does become infected, please be aware that it can spread from dogs to humans via bite wounds, and it is important to see your physician if you feel you may have become infected by your dog or another dog.