旋毛虫不同地理株冷冻耐力的观察

目的观察旋毛虫不同地理株的冷冻耐力。方法将75只雄性昆明小鼠随机分为3组（每组25只），每组分别感染-18℃保存不同时间的旋毛虫河南株、云南株及乡土旋毛虫，每只小鼠经口接种300条肌幼虫。感染后42d剖杀，将全身骨骼肌消化后收集肌幼虫，测定其生殖力指数（Reproductivecapacityindex，RCI）。结果旋毛虫河南株-18℃保存0、6、12h后的RCl分别为91．4、0．03及0（X2=26．453，P〈0．05），云南株-18℃保存0、6、12、24h后的RCl分别为235．6、0．04、0．01及0（x≮21．115，P〈0．05）；乡土旋毛虫-18℃保存0、6、12、24、48h后的RCl分别为34．6、26．8、21．9、10．8及7．4（F=8．505，P〈0．05）。结论旋毛虫河南株与云南株对低温的抵抗力较低，-18℃分别保存12、24h感染性已完全丧失；乡土旋毛虫对低温抵抗力较强，一18℃保存48h仍有较强的感染性。

Studies on the freezing resistance of different Trichinella isolates

Objective To observe the freezing resistance of different Trichinella isolates. Methods Seventy- five male Kunming mice were randomly divided into 3 groups （25 mice per group）. Each group was infected with Henan and Yunnan isolates of Trichinella spiralis （T1） as well as T.nativa （T2） stored at -18℃ for different time,respectively. Each mouse was orally inoculated with 300 muscle larvae. All infected mice were slaughtered at 42 days post-infection. The muscle larvae were collected after all the skeletal muscles were digested,and reproductive capacity index （RCI） were determined. Results The RCI of Henan isolate of T. spiralis stored at -18℃ for 0,6,12 h was 91.4,0.03 and 0,respectively （X2= 26.453, P〈0.05 ）. The RCI of Yunnan isolate placed at -18℃ for 0,6,12,24 h was 235.6,0.04,0.01 and 0, respectively （X2= 21.115,P〈0.05）. The RCI of T.nativa freezed at -18℃ for 0,6,12,24,48 h was 34.6,26.8,21.9,10.8 and 7.4,respectively （F=8.505,P〈0.05）. Conclusions The resistance to freezing of Henan and Yunnan isolates of T. spiralis was lower,their infectivity has completely lost following storage at -18℃ for 12 and 24 h; resistance to freezing of T.nativa was higher,it remains infective after storing at -18℃ for 48 h.