Clinical features of cats diagnosed with coccidioidomycosis in Arizona, 2004-2018

Abstract

Objectives: The goal of this study was to describe the clinical presentation, diagnosis and treatment of coccidioidomycosis in cats residing in a region endemic for Coccidioides species.

Methods: A retrospective review of records was performed at both primary and tertiary care veterinary practices in Tucson and Phoenix, Arizona, USA. Data collected included signalment, clinical signs, physical examination findings, diagnostic test results, treatment and outcome.

Results: Fifty-one feline cases were identified from six veterinary hospitals. Cats presented with clinical signs and laboratory abnormalities similar to what has been seen in dogs, including respiratory illness (n = 20/51), neutrophilia (n = 24/31), monocytosis (n = 17/31) and hyperglobulinemia (n = 16/30). However, cats at diagnosis were typically significantly ill, with 31/51 having disseminated infection, most commonly to the skin (n = 22). Additionally, 43/44 cats that had serum antibody tests performed were positive, and median titer at diagnosis was 1:32 (range 1:4 to ⩾1:256). Serum antibody titers were significantly reduced (P ⩽0.001) in cats that responded to treatment compared with cats that did not clinically improve. Forty of 46 cats that were treated with oral fluconazole responded and did not require additional therapy. Fourteen cats developed recurrent disease and all but one had antifungal therapy successfully reinstituted.

Conclusions and relevance: Coccidioidomycosis is a disease of concern for cats residing in the regions endemic for Coccidioides species. Disease is most often disseminated at the time of diagnosis, possibly due to delays in presentation for care and recognition of the infection. Suspicion of disease, serum chemistries, blood cell counts, presence of antibody and imaging aid in the diagnosis of coccidioidomycosis in cats. Serum antibody reduction during treatment frequently correlated with an adequate response to medication. Consideration of coccidioidomycosis as a cause of illness will lead to earlier diagnosis and potentially better treatment outcomes in cats.

Keywords: Coccidioides; coccidioidomycosis; communicable diseases; epidemiology; mycoses; veterinary.

Figure 1

Lateral and ventrodorsal radiographs of a 3-year-old male castrated domestic shorthair cat, presented for a 2 week history of intermittent coughing, show a multilobular alveolar lung pattern, right caudal lung lobe solitary mass and hilar lymphadenopathy with dorsal displacement of the trachea. Coccidioidomycosis was diagnosed based on radiographic changes and positive serology, and the cat responded to treatment with fluconazole

Figure 2

Pleural effusion and increased opacity in the left cranial lung lobe in an approximately 1-year-old male castrated domestic shorthair found stray 1 month prior to presentation for an intermittent cough. The initial anti-coccidioidal IgG titer was 1:64

Figure 3

Tracheal collapse and a diffuse bronchial pattern in a 10-year-old female spayed domestic shorthair presented for nasal congestion and wheezing of 4 months’ duration. A presumptive diagnosis of asthma was made from radiographs with a bronchial pattern only obtained by another veterinarian 1 month earlier, but the cat did not respond to treatment with prednisolone and amoxicillin/clavulanic acid. The radiologist who reviewed the radiographs commented asthma was the most likely diagnosis and did not include fungal disease in their differential. The initial coccidioidomycosis IgG titer was ⩾1:256

Figure 4

Lytic/proliferative osteomyelitis with soft tissue swelling was identified in a male castrated cat with several months’ history of lameness. The coccidioidomycosis titer was 1:256 at the time of radiography. The lytic/proliferative lesion is characteristic of coccidioidal osteomyelitis, though this cat was not one of the cases reviewed herein

Figure 5

Coronal section of (a) thorax and (b) sagittal section of thoracic spine of a female spayed domestic shorthair with a 3 week history of progressive hindlimb paresis and ataxia with weight loss. (a) The thoracic section shows an enlarged mediastinal lymph node (LN) and pulmonary consolidation, believed to be a granuloma (G), in the right cranial lung lobe. (b) There is a contrast-enhancing, intramedullary lesion of the spinal cord at the level of T8. Coccidioides species spherules were identified by biopsy of a sublingual mass and the cat responded to oral fluconazole