Dirofilaria immitis possesses molecules with anticoagulant properties in its excretory/secretory antigens.

Dirofilaria immitis is a parasitic nematode that survives in the circulatory system of suitable hosts for many years, causing the most severe thromboembolisms when simultaneous death of adult worms occurs. The two main mechanisms responsible for thrombus formation in mammals are the activation and aggregation of platelets and the generation of fibrin through the coagulation cascade. The aim of this work was to study the anticoagulant potential of excretory/secretory antigens from D. immitis adult worms (DiES) on the coagulation cascade of the host. Anticoagulant and inhibition assays respectively showed that DiES partially alter the coagulation cascade of the host and reduce the activity of the coagulation factor Xa, a key enzyme in the coagulation process. In addition, a D. immitis protein was identified by its similarity to the homologous serpin 6 from Brugia malayi as a possible candidate to form an inhibitory complex with FXa by sodium dodecyl sulfate polyacrylamide gel electrophoresis and mass spectrometry. These results indicate that D. immitis could use the anticoagulant properties of its excretory/secretory antigens to control the formation of blood clots in its immediate intravascular habitat as a survival mechanism.

Intracavitary cardiac hydatid cysts with a high risk of thromboemboli. Invasive nature of cardiac echinococcosis.

Hydatid cysts are a serious health problem in many countries that raise farm animals, and they usually involve the liver and lungs. Although cardiac involvement is a rare manifestation of hydatid cyst disease, its early diagnosis and surgical management are crucial. Patients with cardiac hydatidosis may develop acute life-threatening complications secondary to their invasion of surrounding cardiac structures, such as cyst rupture together with systemic and pulmonary dissemination. Therefore, surgical excision is the definitive method of treatment for cardiac hydatid cysts in order to prevent these potential life-threatening complications, even for asymptomatic patients. Herein, we report the case of a 36-year-old man who initially presented with pleuritic chest pain, hemoptysis, and dyspnea. This was followed by the revelation of multiple cardiopericardial hydatid cysts which were discovered via transesophageal echocardiography and multislice computed tomography. In this case, there was a higher risk of cyst rupture and thromboembolism during systemic and pulmonary circulation due to the invasive nature of the cysts which were located in the left atrium as well as between the pulmonary artery and aorta. The patient successfully underwent the removal of the multiple cardiac cysts under cardiopulmonary bypass by taking into account their relationship with the surrounding cardiac structures and the potential risk of local, systemic, and pulmonary dissemination. A pathological evaluation of the surgical specimens confirmed the diagnosis of cardiac echinococcosis and the aggressive nature of the cardiopericardial hydatid cysts by demonstrating their myocardial invasion.

Aortic thromboembolism associated with Spirocerca lupi infection.

A 2-year-old male castrated Cavalier King Charles Spaniel was presented with paraplegia, cold caudal extremities and lack of femoral pulses. A 2cm long thrombus occluding the aortic trifurcation and a 3cm long abdominal aortic aneurysm with a thrombus were detected by ultrasonographic examination. The clinical and ultrasonographic findings were consistent with aortic thromboembolism. Anti-thrombotic and vasodilative therapy was not helpful and the dog was euthanized 3 days after the onset of paraplegia. A thrombus in the aortic trifurcation, multiple thoracic and abdominal aneurysms and a distal mediastinal esophageal granuloma containing Spirocera lupi worms were found on necropsy. The abdominal aortic aneurysms formed by S. lupi larval migration are believed to be responsible for the formation of the thrombus that occluded the aortic trifurcation. This is the first report of aortic thromboembolism associated with S. lupi infection.

Thromboembolism: a rare complication of cardiac hydatidosis.

A cardiac hydatid cyst is rare. We report a case of cardiac hydatid cyst localized in the atria which was diagnosed by two-dimensional echocardiography following a thromboembolic stroke. Surgical resection of the cyst was performed and histopathologic examination confirmed the diagnosis.