艾美耳混合球虫对高原鼠兔致死毒力的初步研究

Effects of Parasitic Eimerians (Eimeria cryptobarretti and E.klondikensis) on mortality of plateau pika (Ochotona curzoniae)

球虫是专一性地寄生于宿主体内且对宿主有很强致死性的一种原生动物。艾美耳球虫是高原鼠兔的主要寄生物。利用艾美耳球虫防治高原鼠兔将具有重要的生态学意义和应用价值。本研究通过人工感染不同剂量的艾美耳混合球虫研究了对高原鼠兔的致死毒力。高原鼠兔的成体死亡率与球虫的感染剂量呈正相关关系,感染600×104个/mL剂量的球虫可导致大部分高原鼠兔成体死亡,而感染60×104个/mL剂量的球虫可导致全部亚成体死亡;成体和亚成体的死亡率无性别间的差异,其死亡时间分别为第4d和第8d。感染60×104个/mL剂量球虫的高原鼠兔随粪便排出的卵囊数量最大。本研究结果表明,艾美耳球虫对高原鼠兔的非急性致死效应类似于慢性杀鼠剂的作用。如果野外大剂量投放艾美耳球虫制剂后,不仅有望短期内有效降低高原鼠兔种群数量,而且其控制效果可具长效性的潜在优点。

Eimeria,one of several genera of protozoans in the phylum Apicomplexa referred to as coccidian,is highly host specific.Infection with coccidia seriously impairs the growth and survival of hosts.Coccidia,thus,potentially are excellent agents for biological control of rodents.We studied effect of coccidia on mortality of plateau pikas（Ochotona curzoniae）.Pikas were given 6 000×104/mL,600×104/mL,60×104/mL,6×104/mL and 0.6×104/mL oocysts each of Eimeria cryptobarretti and E.klondikensis for adults,or 600×104/mL,60×104/mL,6×104/mL of each for sub-adults,by stomach intubation.The prepatent period of adult death was 8 days.The mortality rate among infected pikas was dependent on the initial quantity of oocysts administered.Infection with 600×104/mL oocysts caused most adults to die.In addition,a majority of sub-adults also died after 4 days when they were infected with 60×104/mL oocysts.Not significant difference in mortality was found between males and females.The group infected with 60×104/mL oocysts produced more oocysts than other groups.Our results suggest that it is possible that coccidia,as agents of biological rodent control,could reduce the damages of pika to grassland.