Blastomycosis is a serious fungal disease of dogs, cats, and other animals, including people. The fungus is found in nature in soil, on vegetation, and in pigeon droppings. It is unlikely for it to be transmitted from pets to people unless the fungal forms are passed from an open, running sore of the pet to an open wound of a person. The fungus can exist in two forms: the yeast form found in tissue infections and the mycelial form found in respiratory tissues. Three forms of illness occur: the lung or respiratory form, a form that is disseminated or spread throughout the body, and a skin form.
Blastomycosis is contracted by an animal by inhaling the mycelial form or by direct penetration of the spore form into an open skin sore. Illness typically develops 5 to 12 weeks after infection. The fungus may invade any part of the body, including the brain, bone, and eyes.
One of the most common ways to diagnose blastomycosis is by impression smears, using special stains and microscopic examination of material from open skin sores of the animal.
Important Points in Treatment
1. Blood tests, microscopic studies, cultures, radiographs (x-rays), and special serologic tests are used to confirm the diagnosis.
2. Specific antifungal agents are available to treat the disease, but they can cause a toxic reaction in some animals. Hospitalization is generally recommended for treatment because the drug is usually given directly into the vein and the patient requires monitoring for signs of early reaction to the drug.
3. The prognosis (medical forecast) varies, depending on the location of the primary infection and the sex of the patient (females generally respond better than males). Most deaths occur in the first week of treatment.
4. Over 60% of treated animals recover. As in any other disease, the sooner treatment is started, the better the chances of survival.