Coccidioidomycosis (Valley Fever) in dogs

This is the most severe and life-threatening of the systemic fungal diseases. Coccidioidomycosis is found in dry, dusty parts of the southwestern United States, and in California and neighboring Mexico. (Note that coccidioidomycosis is not the same disease as coccidiosis, a disease caused by intestinal protozoa.)

Infection occurs by inhaling spores. Most cases are subclinical or inapparent. A severe form affects the lungs and produces acute pneumonia. If the disease becomes systemic, it may involve the long bones (most common), liver, spleen, lymph nodes, brain, and skin. Affected dogs will often have a chronic cough, weight loss, lameness, and fever.

The diagnosis is made by identifying the organism (Coccidioides immitis) in cytology, biopsy, or culture specimens.

Treatment: Coccidioidomycosis can be treated effectively using one of the imidazole group of antifungal agents (as described for Histoplasmosis). Prolonged treatment for up to a year is required to try to prevent recurrence. However, relapses are common.