A study of relationship between Leptotrombidium species and serotypes of Orientia tsutsugamushi

1、应用免疫荧光显微技术对恙虫东方体（Ot）进行检测和鉴定。2、虽然一个细恙螨家族系同时感染多种血清型，但我们分析了3个细恙螨家族系，发现每个家族系感染单一血清型。3、在京都某流行区，发现有0.16%的中间叶尺蠖感染。4、从中间叶尺蠖未饲喂的幼虫中分离得到了中间叶尺蠖，这是首次从中间叶尺蠖中分离得到。该分离株的型特异性抗原蛋白基因（tsg）与从患者身上分离的菌株完全相同。这表明中间媒介l .将Ot传播给人类。在不存在白僵菌的地区分离到的白僵菌与从白僵菌中分离到的白僵菌的tsg序列相同。这有力地表明，同一血清型的许多寄生虫寄生在一个以上的物种中。我们从亚洲各地分离的34株菌株的序列中发现tsg基因有很大的区域性差异。这表明Ot血清型在很大程度上取决于每个地区分布的细原体种类。

1, Immunofluorescent microscopy was developed to detect and characterize Orientia tsutsugamushi (Ot) in Leptotrombidium.2, Although it was accepted that one family line of Leptotrombidium is infected simultaneously with several serotypes of Ot, we analyzed three family lines of Leptotrornbidium, and found that each was infected with a single serotype.3, We found that 0.16% of L.intermedium was infected with Ot in an endemic area in Kyoto.4, Ot was isolated from unfed larvae of L.intermedium, this is the first record from L.intermedium. Type specific antigenic protein gene (tsg) of the isolate was completely same to that of a strain isolated from a patient. This suggests that L.intermedium transmits Ot to humans.5, Ot isolated in an area where L.pallidum does not exist had a tsg of the same sequence to that of Ot isolated from L.pallidum. This strongly suggested that Ot of the same serotype parasitized in more than one species.6, We found a great diversity of tsg gene depending on locality from sequences of 34 strains isolated all over Asia. This suggests that Ot serotypes largely depends on Leptotrombidium species distributed in each area.