Valley Fever is caused by a fungus that lives in the desert soil in the areas described in the SW USA at the website above. As part of its life cycle, the fungus grows in the soil (saprophytic cycle) and matures, drying into fragile strands of cells. The strands are very delicate, and when the soil is disturbed – by digging, walking, construction, high winds – the strands break apart into tiny individual spores called arthroconidia or arthrospores. Dogs and people acquire Valley Fever by inhaling these fungal spores in the dust raised by the disturbance. The dog may inhale only a few spores or many hundreds.Valley Fever is considered a noncontagious disease. Even if multiple animals or humans are affected in a household, each infection was acquired by inhaling spores from the soil.
A Valley Fever test, Cocci test, or Cocci titer checks the blood to see if your dog is making antibodies against the Valley Fever fungus. If the test is positive, it means your dog has been exposed to the fungus.
The most common early symptoms of primary pulmonary Valley Fever in dogs are:
* fever (over 102.5 indoors)
* weight loss
* lack of appetite
* lack of energy
If your dog lives in a region where Valley Fever (VF) is typical, your dog could need a Valley Fever test for any illness that manifests the common clinical signs – coughing, fever, weight loss, etc. In addition, your dog will need serum chemistries and white blood cell count and x-rays to aid in diagnosing the illness. A positive test in and of itself is often not enough to diagnose Valley Fever. Some dogs have neg. titres but have VF. Always get at least a lateral x-ray of the chest, as the dog can have cocci in the lungs without a cough and with low titres. Repeat in 2 months. Lab titres within one dilution of change are within normal lab variability, 2 dilutions of a change would be significant. In some dogs, their titre may never go to ‘negative’ may be < 1:4.
Primary disease ; lungs,
Disseminated disease: bones, skin or internal organs,
CNS disease; brain or spinal cord
In most cases, a dog ill enough from Valley Fever to be seen by a veterinarian will require treatment with antifungal medication. Courses of medication for primary disease usually average 6-12 months. Dogs with disseminated disease (in bones, skin, or internal organs) usually require longer courses of medication. Central nervous system (brain or spinal cord) involvement frequently requires lifetime treatment with medication to keep symptoms from recurring. Respiratory illness typically goes away 6-12 months after treatment. Disseminated after 12-18 months or longer of treatment. The disseminated disease group of dogs are more likely to relapse and may need to be on medication for life. (About 30-50% of the disseminated disease group will have recurrances). Conversely, asymptomatic dogs may be immune for life. In a treated dog with primary VF (not disseminated), relapse is unlikely if negative labs and asymptomatic 2 years after treatment.
Check the dogs’ response to meds with CBC and VF titre 6 wks after discontinuing medication. If the dog acts normal with titres the same, one may continue to observe and re-check every 6 months to one year, if negative after several years then may stop testing.
CBC : increase in total WBC’s (mild) and/or increase in monocytes (may use to monitor response to therapy by decrease in monocytes)
Serum: increase in total protein, increase in total globulin (nl = 3-4, increase 5-7 or more)
Oral antifungal medication is the usual treatment for Valley Fever. Ketoconazole (Nizoral) is the most commonly prescribed and the least expensive. Incidence of side effects is relatively high and the drug is usually administered twice daily with food. Fluconazole (Diflucan) is expensive with a low incidence of side effects compared to the other medications. It is administered once or twice daily. Absorption is excellent even on an empty stomach and this drug is often a good choice for very sick dogs that aren’t eating well. Fluconazole is the drug of choice for dogs and cats with infection of the brain, spinal cord, or eyes as it is the only drug that crosses into those tissues.
Fluconazole can be purchased from compounding pharmacies for a reasonable price. Call pharmacies in your area or look on line. Email us for referrals in Arizona.
Additionally, milk thistle may be used for liver support (for a dog on meds) at a dose of 1mg/1#.
New medications: V-fend: variconazole, an azole class drug, not out yet, given PO or IV, and Nikkomycin-Z, not an azole class, currently being developed by Valley Fever Therapies LLC in conjunction with U. of Az.
Complete information on pathology, diagnosis, treatment and prognosis at the Center for Valley Fever website: