Dogs, like people are susceptible to Valley Fever. Valley Fever is caused by a fungus that lives in the desert soil of the southwest United States. The fungus is Coccidioides, so Valley Fever is also known as Coccidiomycosis. Dogs (and people) acquire Valley Fever by inhaling fungal spores in the dust. Sometimes the immune system will destroy the infection in the lungs. This keeps the infection contained about 70% of the time. The sickness occurs when the immune system is unable to contain the infection. The fungus can then spread in the lungs and to other parts of the body.
Valley Fever in the lungs will result in coughing, fever, weight loss, decreased appetite and decreased energy. When the infection spreads outside of the lungs, it causes disseminated disease. These signs can include lameness, back pain and weakness, seizures, soft swelling under the skin, non-healing draining skin lesions, and eye swelling. As you can see from this list, there are no specific signs associated with the disease. It can affect pretty much any area of the body.
Valley Fever is not contagious between animals or from animals to people. This is even the case with draining lesions.
The diagnosis of Valley Fever is made with general blood tests, chest x-rays, bone x-rays, and specific Valley Fever blood tests. Sometimes tests are negative early in the infection so they may need to be repeated. In difficult cases fluid analysis or bone biopsy may be needed. Valley Fever Titers check the blood to see if the dog is making antibodies against the fungus. If the test is positive, a titer will be performed to measure the amount of antibody. Generally, the higher the titer, the more severe the disease. However, very sick animals may not be able to mount an antibody response. Titers usually go down as the dog recovers, but this is not the only measure of improvement.
Treatment generally consists of anti-fungal medication for six to 12 months.
Most dogs will recover with early diagnosis and intervention. Recurrence is possible.
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Mary K. Quinn, DVM
Dogs4Vets Medical Trainer