为观察旋毛虫肌幼虫在小鼠体内的发育过程及特点,取28只雌性昆明小鼠,每鼠经口感染100条旋毛虫肌幼虫,感染后8、9、10、11、13、17、20、23、27、29、50、60、240、400 d各剖杀2只小鼠,取完整隔肌和部分腹肌,醋酸明矾卡红染色后,镜下观查肌幼虫、囊包形态,测量肌幼虫长和宽。结果显示,旋毛虫感染后10、13 d,小鼠膈肌和腹肌中分别发现旋毛虫肌幼虫,以直杆状、弧形居多。感染后17 d,肌幼虫形态以环状、折叠、弯曲、s形、直杆状、弧形为主,囊包雏形形成。感染后29 d,囊包基本发育成熟,囊壁细线状,囊内结构分为两层。感染后60 d,肌幼虫出现蜷曲成团,囊内结构开始出现透明化。感染后400 d,囊包退化,囊内层（深染层）出现透明。旋毛虫感染后10、17、29、60 d,肌幼虫长均值分别为（131.7 ± 21.4）、（435.5 ± 201.5）、（928.4 ± 188.5）、（1044.4 ± 86.7）μm,前后二者差异均有统计学意义（P ﹤ 0.01或P ﹤ 0.05）;肌幼虫宽均值分别为（10.4 ± 2.5）、（22.8 ± 5.2）、（35.0 ± 5.2）、（38.3 ± 3.0）μm,前后二者差异有统计学意义（P ﹤ 0.01）。提示旋毛虫感染小鼠后,肌幼虫及囊包发育大致可以分为成囊前期、囊包发育期、囊包成熟期和囊包退化期等4个时期。肌幼虫和囊包的形态结构变化与感染时间密切相关。

To observe the developmental process and characteristics of Trichinella spiralis muscle larvae in mice, 28 female Kunming mice were orally infected with 100 T. spiralis muscle larvae and each two mice were euthanized at 8, 9, 10, 11, 13, 17, 20, 23, 27, 29, 50, 60, 240 and 400 days post infection. The diaphragm and partial abdominal muscles were collected, sectioned and stained with alum carmine acetate staining. The muscle larvae, larval capsules were observed under microscope. The muscle larvae were found in the diaphragm as early as 10 days post infection (10 d) and in abdominal muscles at 13 d, mostly with straight shape. The larvae were shaped in curve, circle, folded and larval capsules were formed at 17 d. The capsular bags were well developed, the stripes were seen in the wall of the capsule, and the capsule structure was divided into two layers without clear boundary at 29 d. The larvae twisted into a mass, and the structure inside the capsule began to appear transparent at 60 d. The capsule started to degenerate and the wall of the capsule began to appear transparent at 400 d. The average size of muscle larvae was (131.7 ± 21.4) μm × (10.4 ± 2.5) μm at 10 d, (435.5 ± 201.5) μm × (22.8 ± 5.2) μm at 17 d, (928.4 ± 188.5) μm × (35.0 ± 5.2) μm at 29 d and (1044.4 ± 86.7) μm × (38.3 ± 3.0) μm at 60 d, with significant difference in size between each developmental time points (P ﹤ 0.05 or P ﹤ 0.01). According to the experimental results, larval and capsular development can be roughly divided into four stages: pre-encapsulated larvae, larvae with capsular development, larvae with mature capsular bag, and larvae with degraded capsular bag. The morphological structure of larvae and capsules is closely related to the time of infection.