Scanning electron microscopic study of Opisthorchis viverrini tegument and its alterations induced by amoscanate

Abstract

Scanning electron microscopic study of Opisthorchis viverrini tegument and its alterations induced by amoscanate. International Journal for Parasitology 16: 19-26. When examined by scanning electron microscopy, the surface of adult Opisthorchis viverrini is covered with short microvilli that are closely packed together. Microvilli are more numerous and are taller on the ventral surface. Distributed among microvilli are two types of papillae, each one with a dome-shaped base (approx. 3 μm in diameter) with a projecting cilium in one case but not the other. Papillae are scattered in groups over the surface but are especially numerous around the suckers and laterally. When the flukes were treated with a potent schistosomicidal agent, amoscanate (C 9333-Go/CGP 4540), the tegument was damaged. Lesions that occurred on the flukes recovered from infected hamsters 1, 9, 30 and 90 days after treatment were compared with those which occurred when the flukes were exposed to the agent in vitro. Total disruption of the basic structure of the tegument was noted within 2 h of in vitro incubation with 1% amoscanate; the damage was more severe after 24 h of treatment. Flukes obtained from hamsters 24 h after treatment for 4 consecutive days with a total of 40 mg also showed tegumental lesions, including pronounced swellings into large bulbs that eventually ruptured and sloughed. However, complete regeneration of the tegument was noted within 30 days after treatment. © 1986.