Molecular approach to analyze strategies of pathogens in wildlife for acuierement of new host

有些病原体可在人类、家养动物和野生动物之间传播，并引起各种疾病。本研究通过对反刍动物体内寄生的原虫、细菌和病原菌的调查，确定它们能否跨越生物和环境屏障获得新的宿主范围。野生动物体内寄生有这两类寄生虫，但根据核糖体RNA基因分析，它们与家畜的寄生虫没有密切关系。从马场土壤中分离到一株具有毒力质粒的马红球菌，但其质粒类型与欧洲马分离物中分离到的质粒类型相似。因此，致病菌株R.马可能是从欧洲带来的，并在非洲的土壤中殖民。在5种羚羊和犀牛的血液样品中发现疱疹病毒。黑斑羚分离株与家养反刍动物分离株不同，说明本研究中所研究的病原菌与其原宿主存在关联并共同进化，即使在野生动物和家畜密切接触的环境中，它们也不易获得新的宿主。

Some of pathogens are communicable among humans, domesticated and wild animals and cause various diseases. In this study, we investigated protozoan, bacterial and vial pathogens from wild or domestic animals and their environment in order to determine whether they can acquire new host range by crossing biological and environmental barriers.Theileria parasite in ruminants are devided into highly pathogenic and apathogenic species. Wildlife harbor parasites of both categories, but they are not closely related to those from domestic animals on the basis of ribosomal RNA gene analysis. Rhodococcus equi with virulent plasmid are isolated from soil in horse farms, but the plasmid types are similar to those isolated in isolate from European horses. Therefore, pathogenic strains of R. equi may have been brought from Europe and colonized in soil in Africa. Herpesviruses were demonstrated in blood samples on 5 species of antelopes and rhinocerous. The isolate from impala is different from those isolated from domestic ruminants.Taken together, it is concluded that pathogens investigated in this study have been associated and coevolved with their original hosts, and that they are not easily able to acquire new host even under environments where wildlife and domestic animals are in close contact with each other.