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

1、建立了恙虫病东方体（Ot）的免疫荧光显微镜检测方法。2、虽然一个家系同时感染多个血清型的恙虫病东方体已被接受，但我们分析了三个家系，发现每个家系都感染一个血清型。结果表明，在日本京都的中间型钩端螺旋体流行区，有0.16%的中间型钩端螺旋体感染了Ot。型特异性抗原蛋白基因（tsg）与一株患者分离株完全相同。5、在不存在苍白军团菌的地区分离到的Ot与从苍白军团菌中分离到的Ot具有相同的tsg序列。6、从亚洲各地分离的34株Ot中，我们发现tsg基因存在很大的地域性差异。这表明Ot血清型在很大程度上取决于分布在每个地区的纤恙螨物种。

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.