旋毛虫的低温耐受性和感染性的实验研究

Studies on the infectivity and freeze resistance of Trichinella spiralis in mice

目的观察旋毛虫的低温耐受性和感染性。方法 20只雌性昆明小鼠被随机分为对照组和实验组,实验组根据温度不同分3组,共4组,每组5只。对照组每鼠经口感染150条肌幼虫。实验组①组(低温1h组):肉样置于-18℃、1h;②组(低温4h组):肉样置于-18℃、4h;③组(低温24h组):肉样置于-18℃、24h;经低温处理的3组鼠肉取出后,室温下(16℃)彻底融化,磁力搅拌法(消化2h)收集幼虫。然后分别人工灌胃小鼠,每鼠经口感染150条肌幼虫。所有小鼠感染后28d剖杀,取膈肌压片镜检,并用磁力搅拌法收集肌幼虫、计数。结果对照组、低温1h组、低温4h组和低温24h组的肌幼虫均数分别为:5 490.40、2 397.60、319.60、0;低温1h组和低温4h组2组的肌幼虫均数显著低于对照组(P<0.01);低温4h组的肌幼虫均数低于低温1h组(P<0.05)。结论低温(18℃)对旋毛虫具有杀伤作用,旋毛虫囊内幼虫的活力和感染性与冷冻时间和肉样厚度均有直接关系。

Objective To observe the infectivity and freeze resistance of Trichinella spiralis . Methods Twenty female Kunming mice were randomly divided into one control group and three test groups , so 4 groups （ with 5 mice per group） in total . For the control group each mouse was inoculated orally with 150 muscle larvae of T .spiralis . Test Group one＇s samples were stored at -18 ℃ for 1h;test group two＇s samples were stored at -18℃ for 4 h;test group three？s samples were stored at -18℃ for 24 h . All samples were taken out and thawed;muscle larvae of T . spiralis were collected by the magnetic stirrer method . Then , each mouse was orally inoculated with 150 disposed muscle larval of T .spiralis . All infected mice were sacrificed on the 28 th day after infectio , and muscle larval of T .spiralis were examined respectively by diaphragma compression method and digestion method for all infected mice .Results The average number of muscle larvae stored at -18℃ for 1h and 4h were 2 397 .60 and 319 .60 , respectively . These two groups＇ averages were obviously lower than that of the muscle larvae control group （P 〈 0 .01 ） .Group two （4 h）＇s averages were lower than that of the group one （ 1 h） （P 〈 0 .05 ） .Conclusion Freezing does the vital harm to the muscle larval of T . spiralis . The activity and infectivity of muscle larvae are dependent on both freezing periods and muscle depth .