In vitro Effects of Praziquantel on Fibricola seoulensis

Abstract

In vitro effects of praziquantel on Fibricola seoulensis (Trematoda: Diplostomatidae) viability and tegumental and/or parenchymal layer changes were studied by light and scanning electron microscopy after exposing the worms to 0.01-100 ㎍/ml drug concentrations up to 24 hours. The metacercariae (diplostomula) were obtained from the snake, Natrix tigrina lateralis, and adult worms from albino rats 7-9 days after experimental infection. From the view point of worm viability, the lowest effective lethal concentration of praziquantel was 0.1 ㎍/ml. In 1, 10 and 100 ㎍/ml concentrations rapid contraction and immediate death of worms were observed. Severe tegumental and subtegumental changes were recognizable by light and electron microscopy. These changes consisted of bleb formation followed by rupture and loss of surface integrity, and deformity of body configuration. The surface destruction was more pronounced at ventro-lateral margins of the forebody and dorsal junctional area between fore-and hindbody. Widening of the distance oral and ventral suckers was also a prominent feature. Tegumental spines and sensory papillae were least affected.