Spotted fever group rickettsia and the reiervoir in Hokkido and Okinawa, Japan.

斑点热群立克次体(SFGR)对人类的致病性从非致病性到高致病性不等。最近，一种被认为是非致病性的立克次体在欧洲被发现对人类具有致病性。这项研究旨在阐明日本斑点热非流行区SFGR的流行病学和性质。这项研究的监测主要在北海道、冲绳和大阪进行。在北海道对硬蜱属两种动物进行了研究。海氏立克次体(Rickettsia Helvetica)是从日本本土的卵形硬蜱(Ixodes ovatus，LO)中分离到的一种新近发现的致病类立克次体。在Hollaodo从I.ovatus中检测到相同的立克次体未成功。全沟硬蜱中发现的立克次体与分离出海尔维氏立克次体的蓖麻黄单胞菌相似。

The pathogenicity of Spotted fever group rickettsia (SFGR) to human is vary from non-pathogenic one to high pathogenic one. Recently a rickettsia assumed to be nonpathogenic was revealed pathogenic to human in Europe. This study is intended to clarify epidemiology and nature of SFGR in the non endemic areas of Japanese Spotted Fever in Japan. The surveillance of this study is mainly performed in Hokkaido, Okinawa and Osaka. Two species of genus Ixodes ticks were studied in Hokkaido. Rickettsia helvetica that was revealed patogenic to human recently, like organism was detected and isolated from Ixodes ovatus (lo) in the main land of Japan. Detection of the same rickettsia from I.ovatus in Hollaodo is not succeeded. The rickettsiais found in Ixodes persulcatus that is resemble to I.ricinus from which R.helvetica is isolated.