Abstract
The cultivation for development of Ascaris suum from the second-stage larvae($L_2$) embryonated egg and the third-stage of rat-derived larvae($L_3$) recovered from lung of rats were performed to use the screening test of anthelmintics in vitro. The preparations of larvae for cultivation were that the artificially-hatched $L_2$ incubated the embryonated eggs of Ascaris suum in 0.1% formalin solution at $25^{\circ}C$ for 28 days and the rat-derived larvae($L_3$) recovered from the lung of rat infected with the embryonated eggs of Ascaris suum on 7 days after infection(DAI). The cultivation for development of Ascaris suum from the embryonated eggs($L_2$) and the rat-derived larvae($L_3$) for 14 days in RPMI medium 1640(with 5% bovine calf serum) were as follows : 1. The sizes of the liberated larvae($L_2$) which were artificially hatched from embryonated eggs with glass beads(diameter 5mm) were $190{\sim}250{\mu}m$ on 1 days in culture(DIC). The second-stage larvae were molted into third-stage larvae(early $L_3$; $250{\sim}300{\mu}m$) and the features of these larvae were first observed such as cephalic cuticle, esophageal lumen and anus etc. on 5 DIC and the sizes of late third-stage larvae were $250{\sim}450{\mu}m$ on 10 DIC. The sizes of early fourth-stage larvae($L_4$) were $500{\sim}700{\mu}m$ and the features of these larvae were more pronounced in internal organs on 15 DIC. 2. The sizes of third-stage larvae($L_3$) recovered from the lung of rats were $1,340{\sim}1,370{\mu}m$ and the feartures of cephalic cuticle, esophageal lumen, intestine, rectum, anus were visualized by inverted microscope on 1 DIC. The fourth-stage larva($L_4$) completed by third ecdysis were recognizable and sizes of early fourth-stage larvae were developed as $1,400{\sim}2,200{\mu}m$ on 5 DIC. The sizes of middle fourth-stage of larva were $1,900{\sim}2,300{\mu}m$ and the thickened epithelial rectum was observed on 10 DIC. The rectum and anus of late fourth-stage larva($L_4$ $2,500{\sim}3,200{\mu}m$) had developed completely in RPMI medium 1640 on 15 DIC.