Picture this idyllic scene: You and your frisky pooch are walking through your favorite local park, when your pet suddenly catches an intriguing scent in the dirt. They fly into a frenzy, and dig and dig, trying to uncover whatever smelled so tempting, but cannot unearth anything at all. Fast forward a couple of weeks: Your pet is coughing, acting sluggish, shows no interest in any of their favorite treats, and appears to be dropping weight. Concerned, you take your dog to Palisades Veterinary Hospital. Sadly, your pet has valley fever.

What is valley fever in pets?

Valley fever is an infection caused by a type of fungus known as Coccidioides immitis. This disease is extremely common in south-central Arizona, and is also frequently diagnosed in other parts of Arizona, New Mexico’s desert regions, southwestern Texas, California, Nevada, and Utah. People and dogs are most commonly diagnosed with valley fever, but most mammals, including cats, can be infected. The University of Arizona estimates there is one feline case of valley fever for every 50 canine cases. 

Is my pet at risk for valley fever?

As an Arizona resident, your pet is at risk for developing valley fever if they come in contact with infectious Coccidioides spores that live in the desert soil. Coccidioides organisms produce long filaments that contain the infectious spores. When such things as a digging dog, construction, or a windstorm disturb the soil, the spores become airborne and can be inhaled. Dogs are at a higher risk for valley fever than cats because of their digging lifestyle. Cats who go outdoors are at a higher risk than their indoor-only counterparts, since they may dig in the dirt to eliminate and expose themselves to infectious spores.

What are valley fever signs in pets?

About 70% of dogs who inhale infectious spores do not become ill, as their immune system quickly fights off the fungal organism. But, a pet who is exposed to large spore numbers or has a weakened immune system may develop valley fever. Signs can take weeks, months, or sometimes years to appear after exposure, and may include: 

  • Coughing
  • Lethargy
  • Fever
  • Poor appetite
  • Weight loss

Valley fever can also spread outside the lungs, attacking joints, bones, and the brain. For these widespread infections, lameness, seizures, back pain, abscesses, non-healing wounds, eye abnormalities, and heart failure may develop. 

How is valley fever in pets diagnosed?

Valley fever is not always easy to diagnose in pets, but routine cases can be identified with a blood titer test. This test measures the antibody level against Coccidioides, showing whether your pet has been exposed to the fungal organism. General blood tests, such as a complete blood count and chemistry panel, can help rule out other diseases and confirm the diagnosis. 

If the infection has spread outside the lungs, X-rays of the chest or affected bone or joints may be recommended. Open sores and abscesses can be cultured to search for the fungal spores under a microscope, which also leads to a definitive diagnosis. The diagnostic tests we recommend will be based on your pet’s signs, and whether we receive clear results.

How is valley fever treated in pets?

Pets who have been diagnosed with valley fever are prescribed antifungal medications that inhibit Coccidioides growth and allow the immune system to eliminate the infection. If the infection has spread from the lungs, your pet may need anti-inflammatory medications, pain relievers, nutritional support, or fluid therapy. 

Valley fever requires long-term treatment. Antifungal medication is typically given for at least six months to a year, but some pets may need lifelong treatment to avoid relapses. 

How can I protect my pet from valley fever?

While your pet can’t completely avoid exposure to infectious spores—unless they never go outside—you can minimize their risk. Avoid activities that generate dust, such as walking and hiking through desert dirt during extremely dry weather. Restrict your dog from digging and sniffing in rodent holes, and keep them indoors more than outdoors. 

Treating the soil is not practical, as the fungus can thrive in patchy spots and live up to 12 inches underground. However, ground cover that reduces dust, such as grass or deep gravel, is helpful.    

If your furry pal has been digging in the dirt and later has developed an unusual cough, weight loss, or lethargy, they may have contracted valley fever. Contact our Palisades Veterinary Hospital team for an appointment and diagnostic testing to get your pet the treatment they need.