Introduction
“Valley fever,” or Coccidioidomycosis, is a serious fungal disease that, when it becomes disseminated throughout a dog’s body, can be life-threatening. While successful treatment is possible if the infection is properly and promptly diagnosed, treatment can take up to one or more than a year to complete.
Treating Valley fever in Dogs
The therapeutic goals for this disease are preventing further dissemination of the organisms, eradicating the organisms and maintaining the patient’s quality of life. Most dogs are treated as outpatients. Supportive care for these dogs involves restricted activity until clinical signs of the infection resolve. Dogs should be fed a high quality, very palatable diet with free access to fresh water. If necessary, oxygen supplementation can be provided.
Medication Options
Diagnosis should be rapidly followed by medical anti-fungal therapy. The class of anti-fungal drugs currently available is called “azoles,” which include itraconazole, ketoconazole and fluconazole, although of course with time newer medications may become available. Ketoconazole can be effective and is the least costly, but it carries more adverse side effects, including liver damage, vomiting and inappetance. Itraconazole is another antifungal medication that is more expensive than ketoconazole and may or may not have fewer side effects. Fluconazole has the best penetration of the eye and central nervous system, but is the most costly. Whichever anti-fungal medication is chosen, it must be administered precisely in accordance with the veterinarian’s directions. This will normally be 2 times a day, for at least one year. Long-term use of azole drugs can cause liver dysfunction, gastrointestinal upset and skin reactions, so treatment must be closely monitored.
Another anti-fungal medication which can be given intravenously is Amphotericin B. This is used when the dog does not tolerate treatment with the azole drugs, or when the dog is very critically ill, but it carries an increased risk of kidney damage. An even newer drug is Lufenuron, which has shown promising results in the treatment of disseminated coccidioidomycosis in dogs.
Outlook
There is no vaccine currently available for dogs for this disease. The disease cannot occur unless a dog has lived in or traveled through a region where the organism is endemic, so contaminated soil in endemic areas – especially during dust or wind storms after rain – should be avoided. Blood testing every 3 to 4 months after completion of drug therapy is recommended to monitor progress and the possibility of relapse.
Prognosis for dogs with only respiratory signs is quite good. For dogs with disseminated disease, the prognosis is guarded to grave.