Blastomycosis is a fungal infection that causes pneumonia, eye inflammation, lameness due to bone infection and skin ulceration. The disease occurs mainly in the southeast United States, especially in the Ohio, Tennessee and Mississippi River valleys. Dogs inhale the fungal spores, which sets up the lung infection. The infection then spreads to other areas of the body. The signs seen in blastomycosis resemble bacterial infections. Blastomycosis should be considered when the dog does not respond to antibiotic treatment. Antifungal drugs are necessary to effectively treat the infection.