Inoculation of dogs with artificial larvae similar to those of Dirofilaria immitis: distribution within the pulmonary arteries.

Two hundred artificial larvae, similar in size to those of Dirofilaria immitis, were inoculated into the venous system of 20 clinically healthy dogs and the distribution pattern was evaluated. One hundred forty-four (73%) of the larvae were located in the right lung and fifty-one (26%) in the left lung. Of those larvae in the lung, 50% were in the right caudal branch and 21% in the left caudal branch of the pulmonary artery. These findings help to explain why the right caudal lung lobe usually is more affected in canine dirofilariasis.