目的：研究旋毛虫幼虫在成囊前的感染能力。方法：取成囊前发育至不同日龄的幼虫感染小白鼠，经３５ｄ后剖杀检虫并计数。结果：发育至１０ｄ及以前的幼虫无感染能力，发育至１１ｄ及以后的幼虫则有感染能力。结论：成囊前的幼虫需发育到一定程度，才具有感染能力，并随时间而增强，到囊包形成时达到高峰 Objective: To study the infection ability of Trichinella spiralis larvae before encapsulation. Methods: The larvae that developed to different ages before infection into the cysts were infected with mice and the insects were killed after 35 days and counted. Results: The larvae developed to 10 days old had no infection ability, and the larvae developed to 11 days and later had the ability to infect. CONCLUSIONS: Larval larvae prior to laryngeal development need to develop to some extent before they have the ability to infect and increase with time, reaching their peak when the capsular bag is formed