An Equine Case of Parasitic Pulmonary Embolism Resulting from Dirofilaria im itis Infection

Abstract

The case studied was a Thoroughbred colt 3 years and 1 month old. In the posterior portion of the left diaphragmatic lobe of this animal, there was a lesion caused by Dirofilaria immitis. A worm was collected and found to measure 113 mm in length and 600 p in width. It seemed to be immature and female. Microscopical examination of the worm and pulmonary lesion revealed that transverse striations had appeared evidently on the cuticular surface of the worm, but no longitudinal ridges. The findings of the body wall of the worm, including the cuticula membrane, agree with those of Dirofilaria immitis, so far as the cross section of the worm is concerned. Consequently, the size and structure of the worm that could be recognized were consistent in diagnosis with those of Dirofilaria immitis. The changes of pulmonary embolism shown in the present case were similar to those of pulmonary dirofilariasis in the canine case.