Seven dogs 3 to 8 years old manifested such clinical symptoms as a rise in body temperature, anorexia, depression, lameness, astasia, and paralysis or hyperesthesia of the hind quarters. Of them, two took an acute course of 2 and 7 days, respectively, and five a subacute course of 20 to 115 days. Four dogs were subjected to hematological examination, urinalysis, electrocardiography, phonocardiography, radiography, and determination of circulation time. As a result, they showed an increased leukocyte count and radiographic changes of embolism of arteries in the hing quarters, in addition to the ordinary findings of canine filariasis. The other three dogs were in so severe conditions that they could be examined by no tests, except one which demonstrated that they were positive for microfilariae, in blood.
From these results, all the dogs were diagnosed as paradoxical embolism induced by canine filariae. Autopsy revealed that an open condition of the ductus arteriosus (3.5 cm in diameter and 2.4 cm in length) was present in one dog and an open condition of the foramen ovale (from a pin-hole size to about 1 cm in diameter) in the other dogs. Embolism caused by canine filariae was observed in the femoral artery in all the dogs and in the abdominal or thoracic aorta and the renal artery in two dogs.
