Valley Fever in Dogs: What Every Pet Owner Should Know
If you live in the southwestern United States, you’ve likely heard of Valley Fever. While many people are aware that this fungal disease can affect humans, fewer realize that dogs are particularly susceptible. Valley Fever is one of the most common infectious diseases diagnosed in dogs living in or traveling through desert regions, and early recognition can make a significant difference in treatment and outcomes.
What Is Valley Fever?
Valley Fever is a fungal infection caused by Coccidioides species, organisms that live in the soil of arid and semi-arid regions. When the soil is
disturbed by wind, construction, digging, or other activities, microscopic fungal spores become airborne. Dogs become infected by inhaling these spores into their lungs.
The disease is most commonly found in Arizona, parts of California, New Mexico, Nevada, Texas, and other desert areas.
How Do Dogs Get Valley Fever?
Unlike many infectious diseases, Valley Fever is not contagious between animals or from pets to people. Infection occurs when a dog inhales fungal spores from the environment.
Dogs are particularly at risk because they frequently:
- Dig in dirt and soil
- Sniff close to the ground
- Spend significant time outdoors
- Explore dusty environments
Even healthy dogs can become infected after exposure.
What Are the Signs of Valley Fever?
The severity of symptoms varies depending on the dog’s immune response and whether the infection remains confined to the lungs or spreads throughout the body.
Early or Pulmonary Signs
When the infection is limited to the lungs, common symptoms include:
- Persistent cough
- Low energy or lethargy
- Decreased appetite
- Weight loss
- Fever
- Exercise intolerance
Some dogs may have very mild signs that go unnoticed initially.
Disseminated Valley Fever
In some cases, the infection spreads beyond the lungs to other organs and tissues.
This is known as disseminated Valley Fever.
Signs may include:
- Lameness or limping
- Swollen joints
- Back or neck pain
- Bone pain
- Enlarged lymph nodes
- Skin lesions or draining wounds
- Eye inflammation
- Seizures or neurological abnormalities
Disseminated disease is generally more serious and often requires prolonged treatment.
How Is Valley Fever Diagnosed?
Diagnosing Valley Fever often involves a combination of clinical signs, geographic history, and diagnostic testing.
Your veterinarian may recommend:
- Blood tests
- Valley Fever antibody titers
- Chest radiographs (X-rays)
- Cytology or biopsy of affected tissues
- Advanced imaging in certain cases
Because the symptoms can resemble those of cancer, bacterial infections, or other diseases, diagnostic testing is important for obtaining an
accurate diagnosis.
How Is Valley Fever Treated?
Most dogs diagnosed with Valley Fever require antifungal medications.
Common treatments include:
- Fluconazole
- Itraconazole
- Ketoconazole (less commonly used)
Treatment duration varies but often lasts several months and may continue for a year or longer in severe cases.
Regular follow-up examinations and blood testing help monitor response to treatment and detect potential medication side effects.
What Is the Prognosis?
Many dogs with Valley Fever respond well to treatment, particularly when the disease is diagnosed early and remains confined to the lungs.
Factors that influence prognosis include:
- Severity of infection
- Whether the disease has spread
- Overall health of the dog
- Response to antifungal therapy
Some dogs require long-term medication, while others can eventually discontinue treatment after achieving remission.
Can Valley Fever Be Prevented?
Unfortunately, there is currently no vaccine available for dogs.
While complete prevention is difficult in endemic regions, owners can reduce exposure by:
- Limiting outdoor activity during dust storms
- Avoiding heavily disturbed soil when possible
- Discouraging digging behavior
- Keeping dogs indoors during periods of high wind
- Wetting dusty areas before outdoor activities
Because Valley Fever spores naturally occur in the environment, even dogs that spend limited time outdoors can still become exposed.
When Should You Contact Your Veterinarian?
If your dog develops a persistent cough, unexplained weight loss, fever, lameness, or prolonged lethargy—especially if you live in or have recently traveled through the desert Southwest—schedule a veterinary examination promptly.
Early diagnosis often leads to more effective treatment and better long-term outcomes.
Final Thoughts
Valley Fever is a common but often misunderstood disease affecting dogs in the southwestern United States. Although it can be serious, advances in diagnosis and antifungal therapy have greatly improved outcomes for many patients. Recognizing the signs and seeking veterinary care early can help your dog receive the treatment needed for a successful recovery.
If you have concerns about Valley Fever or believe your dog may be showing symptoms, contact your veterinarian for evaluation and guidance.
What About Valley Fever in Cats?
Although Valley Fever is most commonly diagnosed in dogs, cats can also become infected. Fortunately, the disease is less common in cats, but
when it occurs, it may present differently than it does in dogs.
Cats with Valley Fever may develop:
- Fever
- Weight loss
- Decreased appetite
- Lethargy
- Difficulty breathing
- Skin lesions or non-healing wounds
- Swelling under the skin
- Eye inflammation
- Lameness
In cats, the infection is often identified when it spreads beyond the lungs and causes skin, bone, or soft tissue abnormalities. Because these
signs can resemble other diseases, diagnosis may require blood testing, imaging, and examination of affected tissues.
Like dogs, cats are infected by inhaling fungal spores from the environment and cannot spread the disease to people or other pets.
Treatment typically involves long-term antifungal medications, and many cats respond well when diagnosed and treated early.
Pet owners living in areas where Valley Fever is common should be aware that both dogs and cats can be affected. Any persistent respiratory signs, unexplained weight loss, or unusual skin lesions should prompt a veterinary examination.