The actual presence of the worms in the arteries induces an inflammatory reaction causing blood clots (thrombi) to form. (lbah.com)
They found that the presence of worms increased nitrogen content of plants and reduced the number of leaves damaged due to slugs by 60 %. (sciencedaily.com)
Even the small larvae can create enough inflammation to wreak havoc for a cat, while in dogs, the disease is mostly a result of the physical obstruction of blood flow through the heart and lungs by the presence of the worms. (petsinthecitymagazine.com)