Post by neurology admin on Oct 7, 2013 3:06:22 GMT -5
The host may tolerate the worm as long as the embryo is alive. Viable cysticerci are associated with minimal inflammation (vesicular stage). The worm usually dies 2-6 years after infection, and the disintegration of the parasite triggers a vigorous tissue reaction. An inflammatory response to the degenerating cyst results in severe symptoms.
As the cysticerci lose the ability to control the host's immune response, the cyst wall becomes infiltrated and is surrounded by predominantly mononuclear cells. Inflammatory cells enter the cyst fluid (colloid stage). As the host's immune response progresses, fibrosis encompasses the cysticercus, with concomitant collapse of the cyst cavity (granular-nodular stage). The dead parasite decays into eosinophilic desiccated material.
The final stage is a calcified nodule, which presumably forms as a result of dystrophic calcification of the necrotic larva (calcific stage).