Pathognomonic Thoracic Radiographic Findings Are Lacking in Cats with Acute Cytauxzoonosis

Cytauxzoon felis is a tick-borne haemoprotozoan parasite that often causes fatal disease in domestic cats. Histological studies have described substantial pulmonary pathology due to cytauxzoonosis. Published reports were not found describing the thoracic radiographic signs associated with acute cytauxzoonosis in cats. The purpose of this retrospective descriptive study was to describe thoracic radiographic findings in a group of felines with confirmed acute cytauxzoonosis. A total of 37 cats with confirmed cytauxzoonosis and with available thoracic radiographs were included. A subset of 7 cats in this sample also had histopathologic evaluation of their lung parenchyma. Thoracic radiographs were retrieved and reviewed. A bronchial pulmonary pattern was identified as the most common finding (n = 27/37; 73%). Other radiographic findings included cardiomegaly (n = 19/37; 51%), interstitial pattern (n = 17/37; 46%), pleural effusion (n = 12/37; 32%), arterial vascular distension (n = 10/37; 27%), arterial and venous distension (n = 10/37; 27%), and venous distension (n = 1/37; 3%). The primary histological features present in 7 cats with additional histopathologic evaluation, similar to previously published studies, were vascular occlusion. Our study suggests that, despite severe histologic evidence of disease, there are no pathognomonic thoracic radiographic findings in cats with acute cytauxzoonosis.