What Is Valley Fever?

Valley fever is seen in dogs that spend time in the low desert regions of the southwestern United States, including Tucson. While healthy adult dogs may experience no symptoms of valley fever, puppies, senior dogs and dogs with a compromised immune system may show symptoms ranging from coughing to painful joints. Learn more below.

What is valley fever?

The official term for valley fever is coccidioidomycosis, and it is a condition seen in dogs and people. It's also known colloquially as desert rheumatism, San Joaquin Valley fever and California disease.

Valley fever is caused by a fungus called Coccidioides immitis, which lives in the soil and thrives in particular desert climates. In the U.S., Coccidioides immitis can be found in the low desert regions of Arizona, New Mexico, Texas and California.

How is valley fever spread?

Valley fever is spread by inhaling Coccidioides immitis (fungal) spores. When your dog inhales the spores, those spores grow into spherules within the lungs.

If your dog has a strong and healthy immune system, the body will 'wall off' the spherules and your pet will remain asymptomatic (no symptoms of valley fever).

However, if your dog is very young, old or has a compromised immune system, the spherules will continue to grow until they eventually burst, releasing hundreds of endospores that can spread throughout the lungs and other parts of your pet's body. The spherules' growth cycle will then begin again.

Luckily, valley fever in dogs is not contagious between dogs.

How common is valley fever in dogs?

Central and Southern Arizona is believed to have the highest incidence of valley fever in dogs.

In certain Arizona counties, it is estimated that 6% to 10% of dogs will develop symptoms of valley fever.

What are the early signs of valley fever in dogs?

In the early stages, when the spherules are contained within the lungs, symptoms of valley fever typically include:

• Fever
• Dry cough
• Decreased appetite
• Lethargy

Once the fungal spores have reached other parts of your dog's body, more diverse symptoms may appear. These can include:

• Painful swollen joints
• Persistent fever
• Weight loss
• Eye inflammation
• Blindness. In some very rare cases, if the fungus reaches the brain, valley fever can result in seizures.

In some very rare cases, if the fungus reaches the brain, valley fever can result in seizures.

If your dog is displaying symptoms of valley fever, it is essential to seek veterinary care as quickly as possible to avoid serious health complications.

Is valley fever curable in dogs?

When diagnosed and treated early, many dogs recover from valley fever. If a dog is diagnosed with valley fever after the disease has spread to other parts of the body, the disease becomes more challenging to treat — and, in some cases, it can become life-threatening.

What is the treatment for valley fever in dogs?

Antifungal medications are the primary treatment for valley fever in dogs. How long your dog will need to take these medications will depend upon the severity of your pup's condition.

In most cases, antifungal medications will need to be administered for six to 12 months; owners often can see an improvement within a week or two. If valley fever has spread to other parts of the body, your dog may need to continue taking antifungal medications for the rest of their life.

Some of the most common antifungal medications used to treat valley fever in dogs include ketoconazole (Nizoral®), itraconazole (Itrafungol® and Sporanox®) and fluconazole (Diflucan®).