Pulmonary Arterial Lesions of Dirofilaria immitis in the Raccoon Dog(Nyctereutes procyonoides)

Pathological examination was performed on the pulmonary artery of five raccoon dogs (Nyctereutes procyonoides) infected with Dirofilaria immitis. The most significant vascular change exhibited villous intimal proliferation in both the pulmonary trunk and the right and left branches, as the extrapulmonary arteries. The lesion of intimalproliferation was also found in the intrapulmonary artery rich in elastic fibers in all lung lobes, predominantly in the right caudal lobe. In addition, the intrapulmonary arteries revealed fibrous and cellular intimal thickening without villous formation and such a lesion with medial hypertrophy. These pulmonary arterial lesions associated with Dirofilaria immitis infection in raccoon dogs were consistent with those seen in dogs with dirofilariasis in quality, and the lesions were quantitatively more severe than those in dogs.