Valley Fever (VF) is a very serious and potentially fatal disease of animals who live in Desert Southwest- Arizona, Southern California, Southern New Mexico and Southeastern Texas. We see it quite frequently in Tucson.

Valley Fever is caused by a fungus, called Coccidioides immitis, that lives in the soil as spores. Animals become exposed to the fungus by inhaling the spores from the soil either directly (snarfing around in the dirt) or indirectly (dust storms and construction). Nearly every animal that lives in the Desert Southwest for any length of time becomes exposed. Fortunately, most animals’ immune systems fight the fungus and never develop signs of the disease. If an animal’s immune system is not as strong as it should be, or the animal is exposed to a lot of Coccidioides spores, (like hunting dogs, dogs who dig, and animals living near new constructions sites), he/she may develop signs of VF. 


 “Just Ain’t Doin’ Right” is one of the most common signs of valley fever. This is probably due to the waxing and waning fevers and the fugus’ tremendous draw on the body’s immune system defenses.

 Pulmonary (early) Form: Classic signs of VF in dogs include a harsh, dry cough, decreased appetite, and fever. As the disease progresses, the cough may resolve and signs of dissemination (spread around the body) may develop

 Disseminated Form: Coccidioides can spred to almost all organs causing related signs of disease:


Lameness/ limping


Decreased jumping, back pain




Poor appetite, vomiting


Sudden Blindness

Kidneys (rare)

Increased drinking/ urination


  Because the signs of Valley Fever can mimic those of nearly any disease, a blood test must be performed to accurately diagnose the disease. Depending on a patient’s clinical signs, radiographs or other tests may also be recommended. The Valley Fever Center for Excellence at the University of Arizona  is currently promoting several novel methods of diagnosis that may prove helpful in the future as well!


Most patients CAN be cured with long term therapy and committment to veterinary monitoring.

   Treatment involves giving medication daily. Fluconazole is the most widely used medication currently, however, due to suspected resistance of Coccidioides, newer medciations are available and some are in the process of clinical trials!  The length of time that an animal must be treated is variable (usually a minimum of 1 year), depending on the severity of disease and the pet’s individual response to treatment. The response to treatment is determined by monitoring blood tests and/ or radiographs every few months.

Depending on a patient’s signs, surgery may be needed to improve a patient’s response to therapy.  For instance, sexually intact pets should be spayed or neutered as the fungus loves to “hide out” in reproductive tissue.

 It is critical to continue medication until your veterinarian saysthat it is safe to stop medication.

Stopping medication prematurely will only result in relapse of signs later and may induce a chronic, incurable infection

 Your veterinarian will use the data from blood tests, radiographs and physical exams, as well as  information provided by rapidly changing, late-breaking research to help determine when it is safe to discontinue medication.

 ** Even after a patient is “cured”, according to his clinical signs and bloodwork, relapses or re-infection may occur. It may, therefore, be recommended that a pet’s blood be rechecked at intervals for several years after recovery.

  Early detection can save a pet’s life.

 If your pet has any signs that might suggest Valley Fever and he has been living in or passed through the United States Desert Southwest,  please do not hesitate to have him examined and tested by your veterinarian!

 Learn More from the University of Arizona Valley Fever Center for Excellence