If you live in the southwestern United States -- from Texas to southern California and as far north as Nevada -- your dog is at risk for contracting coccidiomycosis. You're also at risk for this fungal disease, better known as valley fever. However, since the fungus responsible for the disease, Coccidiodes immitis, lies in the soil, canines are especially vulnerable. Inhaling just a few spores while digging or rolling in the dirt is all it takes for infection.
If a dog inhales Coccidiodes immitis spores, they lodge in his lungs and continue growing. At some point, the spores rupture, spreading tiny endospores into his system. If they spread only in the lungs, the dog will suffer from the less severe of the two canine forms of valley fever. In the more severe form, the spores can disseminate throughout the body. If that happens, your dog might never fully recover. If untreated, he's likely to die. Symptoms generally appear within three weeks of exposure. Healthy dogs might never show obvious signs of the disease. Fortunately, valley fever isn't contagious. Dogs contract it only from direct spore inhalation.
Coccidioidomycosis Symptoms and Diagnosis
The first sign of the disease is usually a persistent, dry cough. The dog might stop eating and lose weight. Affected dogs often spike fevers and become lethargic. If valley fever spreads in his body, your dog might experience constant infections, joint pain and difficulty walking. In worst-case scenarios, the fungus invades the brain, resulting in seizures and other neurological disorders. Serious symptoms generally develop in older canines or those with compromised immune systems. Diagnosis requires expensive blood testing, X-rays and possibly biopsies or cultures. A vet might make a presumptive diagnosis based on clinical signs and blood titer test results. Veterinarians outside the Southwest might not recognize initial symptoms as valley fever. If you've traveled to valley-fever-prone regions with your dog, let your vet know.
Treating valley fever involves a combination of symptom relief, supportive care and antifungal medication. Drugs of choice include ketoconazole, fluconazole or itraconazole. Your vet prescribes a particular medication based on your dog's overall health. For example, fluconazole isn't appropriate for dogs with kidney ailments. All three drugs can cause gastrointestinal upset and high liver enzymes. Pregnant or nursing dogs should not receive these medications. Seriously ill dogs might require intravenous administration of Amphotericin B. That drug is also used for dogs who don't respond to conventional oral drug treatments.
Length of Treatment
Curing your dog of valley fever isn't a quick process. Your dog receives pills twice daily for a long period -- perhaps six month to a year, depending on the medication. During the treatment period, you and your dog must make regular visits to the veterinarian so she can monitor his antibody levels. That continues every few months until his levels fall back into an acceptable range.
Symptom and Supportive Treatment
Your vet might prescribe anti-inflammatories and steroids for pain relief if your dog is seriously ill, along with cough suppressants if that's an issue. If your dog isn't eating well, your vet might recommend a special diet. Severely sick dogs require hospitalization until stabilization. In a worst-case scenario, the dog might require surgery for removal of an affected organ.
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.