云南省安宁市鼠类感染肝毛细线虫情况调查和实验动物宿主的研究

Capillaria hepatica Infection in Rodents from Anning Prefecture of Yunnan Province and Experimental Research on Host Animals

目的了解云南省安宁市农田鼠类肝毛细线虫（Capillariahepatica）的感染情况，并观察其对sD大鼠和昆明小鼠的易感性。方法于2010年3月--2012年3月，在云南省安宁市温泉镇农田中布放鼠夹捕鼠。捕获的鼠经实验室鉴定鼠种后．剖检肝脏，压片镜检虫卵形态，统计肝毛细线虫的自然感染率。分离肝毛细线虫虫卵，体外培养后．经口感染SD大鼠和昆明小鼠各4只，每只感染约1000个虫卯，相应对照组（各4只）则灌喂生理盐水。分别于感染后30d和80d各剖杀SD大鼠和昆明小鼠2只，观察肝脏病变情况，HE染色观察肝组织切片。结果捕获鼠类8属10种共115只．肝毛细线虫总感染率为22．6％（26／115），雌鼠肝毛细线虫感染率（22．5％，18／80）与雄鼠（22．9％，8／35）比较，差异无统计学意义（P〉0．05）。其中褐家鼠的感染率最高，捕获的11只中有10只感染。剖检感染鼠肝脏．肉眼可见其表面有颗粒状白色或淡黄色小结节。大小为0．1--0．2cm。结节压片后镜下见大量肝毛细线虫虫卵，呈椭圆形，大小为（50--65）μm×（25--30）μm。感染小鼠肝组织中的结节压片镜检和HE染色结果显示，感染后30d．SD大鼠肝脏内发现被纤维包裹的肝毛细线虫成虫和虫卵，肝小叶间间质纤维形成；昆明小鼠肝脏内未发现肝毛细线虫成虫和虫卵，但有炎症细胞浸润。感染后80d，SD大鼠肝脏内有大量虫卵，结节内出现钙化的成虫残体；昆明小鼠肝脏内发现成虫和虫卯．但未发现问质纤维发生。结论云南省安宁市野生鼠类中褐家鼠的肝毛细线虫感染率较高．SD大鼠和昆明小鼠均为肝毛细线虫的易感宿主。

Objective To investigate the prevalence of Capillaria hepatica in rodents from Anning Prefecture, Yunnan, and observe the susceptibility of C. hepatica to SD rats and KM mice. Methods Rodents were trapped in a cultivated filed of Wenquan Town, Annning from March 2010 to March 2012. The species of rodents were identified. The liver was examined and a microscopic examination of tissue was performed by the tissue press technique for the presence of the typical bipolar eggs, adults or larval stages. The prevalence of C. hepatica in rodents was calculated. C. hepatica eggs were collected and cultured in vitro. Each SD rat or KM mouse was orally infected with approximately 1 000 C. hepatica eggs. The control groups with 4 SD rats or 4 KM mice received only normal saline. The experimental animals were euthanized at the 30th and 80th day post infection. Collected liver samples were processed for gross patho- logical and histological section examination. Results A total of 115 rodents were captured and examined. C. hepatica eggs were found in 26 （22.6%） rodents. There was no significant difference in the prevalence between female （22.5%, 18/80） and males （22.9%, 26/115）（P〉0.05）. The highest prevalence was found in Rattus norvegicus （10/11）. Pathologi eal findings showed numerous white-yellow small nodules ranged from 0.1-0.2 em in diameter. Under light microscope, C. hepatica eggs were ovoid [（50-65） ~mx（25-30） Ixm]. At the 30th day post-infection, there were several adult worms and their eggs delimited by a fibrous capsule, and septal fibrosis formations occurred in the liver of SD rat. No worm oreggs were found in the mouse liver, but the liver presented inflammatory cell infiltration. At the 80th day post-infection, live worms disappeared from the focal lesions in the liver of SD rat, being replaced by partially calcified worm debris. Mature worms and eggs were seen in the KM mouse fiver, however, septal fibrosis was absent. Conclusion This study has documented a high prevalence of C. hepaticum in R. norvegicus from Arming Prefecture. SD rat and KM mouse are the susceptible hosts of C. hepatica.