Coccidioidomycosis, also known as Valley Fever, is caused by the fungus Coccidioides immitis. This disease is rarely found outside of the endemic region of the Lower Sonoran Life Zone, encompassing the dry, southwestern United States, Mexico, and Central and South America. The most common areas in the United States in which coccidioidomycosis is found include California, Arizona, and southwestern Texas. Infection occurs when a cat inhales infective spores of C. immitis from the soil, and this is more likely after dry soil has been disturbed, such as after a dust storm, earthquake, or construction. This disease occurs in many mammals but is less common in cats than in dogs. 

Clinical signs of feline coccidioidomycosis are not specific to this disease, and often include fever, anorexia, and weight loss. Skin disease is also commonly seen, such as draining tracts, abscesses, and enlarged lymph nodes. Ocular changes and lameness are possible signs of feline coccidioidomycosis, though respiratory problems are relatively uncommon in cats and seen less often than in other animals with the disease.  Diagnosis of this disease can be very difficult in cats, and is usually made through visualization of fungal organisms under the microscope. However, coccidioidomycosis should be considered in cats with consistent clinical signs within the endemic region. Treatment involves an extended course of antifungal medications, and unfortunately, the long-term prognosis for cats with coccidioidomycosis is guarded as relapse of disease is very common following initial treatment. 

Last updated 2021