The Diagnosis, Treatment, and Potential Prevention of Coccidioidomycosis in Dogs

Presentation Description / Summary: Coccidioidomycosis (Valley Fever) is a systemic primary fungal infection of dogs, humans, and other mammals.  It is endemic to the Southwestern United States and Mexico in North America.  The majority of cases occur in Arizona and California.  However, the endemic region is expanding, and climate modeling predicts that the entire Western US states could support the growth and transmission of Coccidioides by the end of the century.  Coccidioidomycosis is of national importance because dogs that travel or winter in the endemic areas, or are relocated from endemic shelters to distant sites across North America, may become ill far from where the disease is common. Infection usually occurs via inhalation, causing mycotic pneumonia and other thoracic disease, and it easily disseminates outside the lungs and thoracic cavity.  Disease awareness and collecting a good travel history are critical for considering a diagnosis of coccidioidomycosis.  Diagnostic approach includes routine blood work, serology, and radiography of suspected sites of involvement, particularly lungs and bones.  More extensive diagnostics may be needed to render a diagnosis, including advanced imaging, cytology, biopsy, or culture.  Rates of complication in dogs are 5-10 fold as high as in humans and current standard of care is to treat all clinically ill dogs with antifungal medication.  Treatment is protracted, usually a minimum of several months to years, and drugs require monitoring regularly for efficacy and adverse effects. Fluconazole and itraconazole are common first line agents, while amphotericin B, posaconazole and voriconazole are usually reserved for life-threatening or refractory illness.  Coccidioidomycosis takes a considerable toll on canine lives, potentially resulting in debilitation, lifetime treatment to maintain disease remission, owner surrender because of costs, and death. An avirulent, live vaccine to prevent or mitigate coccidioidomycosis in dogs is in advanced stages of development and undergoing USDA review.  Success with the canine vaccine is a stepping stone to humans.