Faust Animal HospitalValley Fever
by Dr. Teri Wiblin, D.V.M
Coccidioidomycosis, or Valley Fever, is a common disease in the
Southwestern United States. It is caused by an organism called
Coccidioides immitis. Coccidioides is a dimorphic fungus,
which means that it occurs in two forms. In its infective form it is
mold, which naturally occurs in the soil of arid regions. The mold
spores are breathed into the body from contaminated soil or dust. Once
it enters the body, it transforms into a yeast. The yeast form is not
contagious. You, and your other pets, cannot catch Valley Fever from an
infected pet, or even from an infected human.
Most commonly, Valley Fever infects the lungs and causes coughing, or in severe cases may cause breathing difficulty. Valley fever also commonly affects the bones and the central nervous system, usually the brain. Less commonly, it may affect other organs, including the skin, eye, spleen, pancreas, reproductive system, and even the heart. The symptoms of Valley Fever depend on the organ system(s) involved with the infection.
The diagnosis of Valley Fever is made on the basis of clinical signs, or symptoms, as well as laboratory and radiographic (X-Ray) tests. X-Rays may show a lesion, or abnormality, depending on where the infection is located. Usually if the lesion is on a bone or in the lungs, it is fairly easy to see on an X-Ray. If the lesion is in another part of the body it may be more difficult to visualize on an X-Ray. Sometimes more advanced radiographic procedures, like CT scans, may be necessary to visualize the lesions, especially if they are in the brain. Blood testing for Valley Fever provides us with a titer level. A titer indicates a level of infection. Titer results of less than 1:32 usually indicate that the disease is localized to one body part or system. Titer levels above 1:32 indicate that the disease has disseminated or "spread" beyond the initial infection point.
Treatment for Valley Fever is generally accomplished with "–azole" antifungal drugs. These include ketoconazole (Nizoral), itraconazole (Sporonox), or fluconazole (Diflucan). The choice of medications depends on the location of the disease, the severity of the disease, and economic decisions. Valley Fever is an expensive disease to treat. None of the drugs used to treat Valley Fever are cheap, and treatment is often prolonged, often requiring a year or more of therapy.
The prognosis for Valley Fever depends on the anatomic location, but is usually favorable. Non-complicated Valley Fever in the lungs usually resolves within a few months and the patient feels better within days of starting treatment. Valley Fever in the bone may take a year or more of continuous treatment, and sometimes the lesions never completely resolve.
Monitoring Valley Fever after the onset of treatment is crucial. This may require blood tests to check the titer level as well as X-Rays to monitor the lesions. Deciding when to stop treating Valley Fever is often very difficult. A decision to stop is often made when the blood tests show that the titer level has dropped to a reasonable level, the patient is free of radiographically visible lesions, and the symptoms have resolved. If the therapy is stopped to soon, the patient may have a relapse; if stopped too late he/she has been treated unnecessarily. Ideally, the patient would be treated until the titer is negative, but sometimes this never happens.
We recognize that treating Valley Fever may be a strain on your budget, and are committed to trying to treat the disease as economically as possible. We work with a number of local pharmacies to try to insure that your pet gets the medications he/she needs at a reasonable price.
Working together, we can usually cure this infection. If you have questions regarding Valley Fever, and your pet’s treatment, please don’t hesitate to call.