In the past few months we have seen multiple cases of Blastomycosis, a fungal disease caused by Blastomyces dermatitidis. This fungus is commonly inhaled and settles in the respiratory tract where the moist environment encourages the spores to reproduce. On rare occasion, spore can enter the body through an open wound. It can spread to other organs, generally the eyes.

Blastomycosis most commonly affects dogs, but rare infections have been seen in cats and humans. Dogs are 10 times more likely to be infected than humans, and 100 times more likely than cats. The spores are found in the soil and environment, commonly near bodies of water.


  • Fever
  • Coughing
  • Respiratory Distress
  • Loss of Appetite
  • Weight Loss
  • Lethargy and/or Depression
  • Draining Skin Lesions
  • Blindness
  • Lameness
  • Seizures
  • Enlarged Lymph Nodes


The veterinarian will likely recommend radiographs which can show changes in lung patterns. A sample can be obtained from an open wound, the respiratory tract, a lymph node or nodule. This sample is then placed on a slide, stained, and examined under microscope for Blastomyces fungal spores. The most common test we use to diagnose Blastomycosis is the MiraVista Blasto Quantitative Antigen EIA. Serum or urine is sent out to the lab for a quantitative (gives you a number) result.


Anti-fungal medications are necessary to kill the fungal spores. Often patients stay on these medications for up to 6 months, depending on follow up test results. Since a large amount of the fungi reside in the lungs, when they die they can trigger an inflammatory response causing respiratory distress or failure. This usually happens within the first 24-72 hours of treatment. During this period, hospitalization may be required including oxygen therapy, IV fluids, and other supportive care.

Radiographs can be taken prior to and during treatment to assess the condition of the lungs. Follow-up antigen testing will determine if medication can be discontinued. Pets who live in areas with high infection rates should be tested often or kept on anti-fungals according to your veterinarian’s recommendations.


Unfortunately, there are no ways to prevent your pet from getting Blastomycosis. Know the area where you live, ask your neighbors, check with your local veterinarian to see if you live in a “hot spot”. Clients who live in these areas should be hypervigilant of any respiratory issues or oozing sores.

“Testing the environment for Blastomyces isn’t likely to be useful. When a soil sample tests positive for Blastomyces, it isn’t necessarily a source of infection, and when a sample tests negative, that doesn’t necessarily mean that the fungus isn’t in the soil. Also, there are no commercially-available tests to detect Blastomyces in the environment. Testing environmental samples for Blastomyces is currently only done for scientific research.”

At Northern Veterinary Clinic, our staff has had extensive experience diagnosing and treating Blastomycosis patients, including our own pets. We would be happy to answer your questions and address your concerns regarding this disease. Give us a call today at 444-5797 to schedule an appointment for your pet.