Diagnostic Contribution of Bronchoalveolar Lavage Sampling and Fungal Culture in a Dog With Pulmonary Coccidioidomycosis

A 7-year-old, male neutered, Miniature Australian Shepherd from Arizona was presented for evaluation of a 3-month history of progressive cough. Thoracic radiographs revealed a focal alveolar pulmonary pattern and suspected tracheobronchial lymph node enlargement. Serum anti-Coccidioides spp. IgM/IgG antibodies were not detected by agar gel immunodiffusion performed by 2 different reference commercial veterinary laboratories approximately 3.5 and 3.75 months after respiratory tract signs were first noted. The dog failed to respond to empiric therapy with a cough suppressant and various antibiotics. Tracheobronchoscopy and bronchoalveolar lavage (BAL) were subsequently performed and cytological examination of the BAL fluid identified marked neutrophilic inflammation characterized by mildly degenerate neutrophils and no infectious organisms. Bacterial cultures were negative but fungal cultures revealed growth of Coccidioides spp. Clinical signs improved shortly after initiation of fluconazole administration and the dog achieved long-term sustained clinical remission. Here, we provide a description of a dog with pulmonary coccidioidomycosis diagnosed with fungal culture of BAL fluid. Airway sampling with cytological examination and fungal culture should be considered in dogs with persistent respiratory related clinical signs, negative antibody serology, and that have lived in or traveled to endemic areas.