Valley fever, or Coccidioidomycosis, is a disease that can occur in dogs, and people, from inhaling the fungus Coccidioides immitis. The fungus lives in desert regions of the southwestern United States, and it can become airborne when the soil is disturbed. The symptoms of Valley fever in dogs vary, and it can be a difficult disease to diagnose and cure. Valley fever cannot be transmitted between people and dogs, and dogs cannot transmit the disease to other dogs.
In southwestern areas of the United States, particularly in dry desert regions, the fungus Coccidioides immitis lives naturally in the soils. During periods of drought, the fungus goes into a dormant stage. However following periods of rain, the fungus becomes a mold and releases spores into the air.
Upon inhalation of the fungus, a dog may either have no reaction, or the dog may develop one of the clinical forms of the disease. The first form of the disease, the primary form, manifests as a chronic respiratory disease. The dog may experience mild coughing and loss of appetite. The second form of the disease, the disseminated form, occurs when the fungus spreads to other tissues within the dog’s body.
Some dogs seem to be resistant to the fungus, but other dogs develop a severe disseminated form of Valley fever in which the fungus spreads throughout the tissues of the body. Treatment for disseminated Valley fever is needed, or the condition can become life threatening. While successful treatment for Valley fever is possible, the treatment can take up to a year to complete.