Fifty apparently healthy island dogs presenting to the Ross University School of Veterinary Medicine (RUSVM), St. Kitts, West Indies for neutering were used in this prospective study. Twelve of the dogs (24%) were diagnosed with spirocercosis based on a positive fecal analysis and characteristic lesions seen during esophagoscopy. Routine thoracic survey radiographs revealed changes previously reported with spirocercosis in 10/12 (sensitivity
= 83%) infected dogs, but in none of the uninfected dogs (38/38; specificity = 100%). The most common radiographic changes were an increased fluid density within the caudal
dorsal thorax on the lateral view and a widening and/or bulging of the caudal mediastinum on the dorsoventral view. After oral administration of barium sulfate, barium retention or a tortuous esophagus was visible in all infected dogs (12/12; sensitivity 100%) and in one
uninfected dog (1/38; specificity 97%). The results show spirocercosis is common on St. Kitts and that radiographs are as dependable as fecal analysis and/or endoscopy in
diagnosing the condition.