Southcentral Division 2021

Signalment:8-year-old male American Bulldog/pitbull mix

History:Submitted as a legal case for “caught in the crossfire of a gunfight” with no medical history.

Gross Lesions:There were more than eighty long, slender, white nematodes consistent with Dirofilaria immitis in the right ventricle extending into and expanding the pulmonary artery, and at least five worms in the caudal vena cava. The lungs were diffusely firm and rubbery and failed to collapse, and off-white to pale beige with a brown-orange tinge and multiple hemorrhagic foci throughout all lobes. There was an 8 x 13 x 8mm nodule in the cranial aspect of the right cranial lung lobe and a second nodule measuring 2 cm in diameter in the middle of the right caudal lung lobe – on cut surface, both were purple-brown and spreadable (necrosis). There were a minimum of thirty heartworms measuring up to 29cm in length in the main artery of the right caudal lung lobe, and some extended into the area of necrosis. A minimum of five heartworms were also present in the right caudal mainstem bronchus. On cut surface of the right cranial lung lobe, two large vessels were enlarged and thrombosed, with heartworms incorporated in the thrombi. The left caudal lobe was similar to the right side, including a thrombus and the presence of heartworms; heartworm burdens were heavier in the caudal lung lobes. There were approximately ten heartworms in the accessory lung lobe.