Morphological changes in cysticerci of Taenia taeniaeformis after mebendazole treatment.

The progressive micromorphological changes in Taenia taeniaeformis cysticerci, induced by a single parenteral treatment of the infected mice with mebendazole, are described. The time-related alterations concerned the tegument and tegumental cells and were successively: disappearance of microtubules, accumulation of secretory substances in the Golgi areas, decrease in number to complete loss of microtriches, "ballooning" of all tegumental cells with subsequent burst, vacuolization and degeneration of the tegument, and finally necrosis of the pseudoproglottids. Similar but less pronounced injuries were seen in the scolices, although microtubules disappeared as early as in the pseudoproglottids. Microtubules from the host tissues remained intact. The meaning of the apparent primary interference of mebendazole with the microtubular system in relation to the subsequently observed death of the cysticercoids is discussed.