Hi stranger! Signing up for MypetMD is easy, free and puts the most relevant content at your fingertips.

Get Instant Access To

  • 24/7 alerts for pet-related recalls

  • Your own library of articles, blogs, and favorite pet names

  • Tools designed to keep your pets happy and healthy

or Connect with Facebook

By joining petMD, you agree to the Privacy Policy.

PetMD Seal

Fungal Infection (Blastomycosis) in Cats


Blastomycosis in Cats


Blastomycosis is a systematic yeastlike fungal infection caused by the organism Blastomyces dermatitidis, which thrives in wet environments, such as riverbanks, lakes and swamps, where damp soil lacking direct sunlight fosters growth of the fungus. The fungus is also present in areas that are rich in decaying matter, such as wooded areas, forests, and farms. It is a naturally occurring North American fungus, with the highest prevalence of infection taking place in geographic areas located near water -- such as the Mississippi, Ohio, Missouri, and Tennessee River basins.


Symptoms and Types


  • Difficulty breathing
  • Skin lesions




Blastomycosis typically occurs when a cat inhales the airborne fungal spores of the genus Blastomyces dermatitidis after the contaminated soil has been disturbed. This can be from an activity as benign as digging in the dirt or following a scent trail. The spores can also enter through the skin. Exposure to areas with water, decaying matter, or recently excavated areas increase the risk of exposure to the fungus and consequent development of the disease.




Care must be taken to test properly for this condition, since it is commonly misdiagnosed, which can lead to permanent or fatal damage. It may be mistaken for cancer and mistreated, or it may be mistaken for a lung infection of bacterial origin and treated with antibiotics, which puts your cat at greater risk. You will want to ask your veterinarian to test for fungal infection if your cat has been in an environment where the blastomyces fungus might have been present at any time in the six weeks previous to the onset of symptoms.


The best methods for diagnosing blastomycosis is through examination of the cells in the lymph nodes, an analysis of fluid drained from skin lesions, a tracheal (windpipe) wash for collecting tracheal fluids, and an examination of lung tissues. Tissue samples may also be taken to check for the presence of fungal organisms, especially if there is no productive cough (productive, meaning that fluids are produced). Other tests that may help diagnose blastomycosis include a urine analysis, and an X-ray of your cat's lungs.




Related Articles

Pneumonia (Interstitial) in Cats

Pneumonia refers to an inflammation in the cat's lungs. Interstitial pneumonia, meanwhile, refers to a form of pneumonia in which the inflammation...

Upper Respiratory Infection (Chlamydia) in Cats

Chylamydiosis in cats refers to a bacteria based chronic respiratory infection. Animals that have developed this infection will often exhibit...

Pus in the Chest Cavity of Cats

Pyothorax occurs when pus, the body's natural immune response to an invasion of bacteria, accumulates in the chest (pleural) cavity. Made up...

Fluid in the Chest in Cats

Chylothorax is a medical condition that results from the accumulation of lymphatic fluid in the chest cavity where the heart and lungs reside,...