Lymphographic changes in young dogs after transplantation with adult worms of Dirofilaria immitis into the abdominal cavity.

Serial lymphographic studies were made in 4 dogs transplanted with adult worms of Dirofilaria immitis. Several changes of the lymphatic systems of the treated dogs such as dilatation, narrowing, tortuosity, backflow, collateral flow, leakage and lymphorrhea of lymphatics, as well as enlargement and filling defect of lymphnodes were observed at first 2 months after transplantation, comparing with the lymphograms before transplantation. Lymphographies were repeated further 4 and 7 months after transplantation. In our previous studies, the mechanism of chyluria due to human filariasis was not sufficiently explained beyond the speculation of the mechanical obstruction of lymphatic vessels by worm bodies. In the present studies, varied abnormal changes, especially back and collateral flow of the lymph vessels of popliteal and inguinal regions, could be produced in lymphatic systems in dogs by transplantation with adult worms of Dirofilaria immitis into peritoneal cavity. This fact suggests that a mechanism of filarial chyluria is due to systemic responses and changes of the lymphatics by substance of the body of filarial worms.