草原道路对狭颅田鼠肝毛细线虫感染率影响的初步调查

A preliminary investigation of effects of grassland road on Capillaria hepatica infection rate in Microtus gregalis

目的 探究草原道路对狭颅田鼠种群密度、肝毛细线虫感染率和感染度的影响。方法 2006年7-8月,在内蒙古自治区(内蒙古)锡林郭勒盟西乌珠穆沁旗典型草原上,选择以狭颅田鼠为优势鼠种的草场,开展草原道路与狭颅田鼠肝毛细线虫感染率关系的研究。实验共分设2个实验样地,其中紧邻草原道路的为实验组路边样地,远离草原道路500 m为对照组草地样地,每个样地平均分为6个小样区。使用鼠夹基本捕尽各小样区内的狭颅田鼠,然后统计捕获数量,对捕获个体进行解剖。将感染肝毛细线虫情况由轻到重分为4个级别(0~3级),记录感染情况,统计感染率。采用独立样本t检验统计数据。结果 实验组和对照组不同样区内狭颅田鼠肝毛细线虫的平均感染率分别为(26.15±4.28)%和(16.23±3.38)%,二者差异有统计学意义(t=4.108,P=0.002);2组间各样区感染个体的平均感染度实验组为1.55,对照组为1.15,二者差异亦有统计学意义(t=3.908,P=0.003);而捕获的狭颅田鼠平均数量实验组为23.17只,对照组为21.33只,2组间差异无统计学意义(t=1.003,P=0.339)。结论 草原道路未对狭颅田鼠种群密度产生明显的影响,但紧邻草原道路的狭颅田鼠种群比远离草原道路的该鼠种群更易感染肝毛细线虫,且情况更严重。草原道路可能对肝毛细线虫传播具有一定的促进作用,应加以防范。

Objective To study the effects of grassland roads on the density of Microtus gregalis and the rate and degree of Capillaria hepatica infection in M. gregalis. Methods From July to August 2006, in typical grassland(where M.gregalis was the dominant rodent species) in West Ujimqin Banner, Xilin Gol League, Inner Mongolia Autonomous Region, China, the relationship between grassland roads and the rate of C. hepatica infection in M. gregalis was investigated. The grassland was divided into experimental area(close to the grassland road) and control area(500 m away from the road). Each area was equally divided into six plots. Almost all narrow-skulled voles in plots were captured using rodent traps. The infection rate of C. hepatica was divided into four levels(0-3) from mild to severe. The infection rate was recorded and the independent sample t test was used to analyze data. Results The mean C. hepatica infection rate of M. gregalis was statistically higher in the experimental plots than in the control plots [(26.15±4.28)% vs(16.23±3.38)%,t=4.108, P=0.002]. The mean infection level of the infected voles was statistically higher in the experimental plots than in the control plots(1.55 vs 1.15, t=3.908, P=0.003). There was no statistical difference in the mean number of captured narrow-skulled voles between the experimental and control plots(23.17 vs 21.33, t=1.003, P=0.339). Conclusion Grassland roads have no statistical impact on the density of narrow-skulled voles, but narrow-skulled voles living close to grassland roads are more likely to have C. hepatica infection, which tend to be more severe, compared with those away from grassland roads. Grassland roads could promote the spread of C. hepatica, which should be paid attention to.