New Record of the Scrub Typhus Vector, Leptotrombidium rubellum, in Southwest China.

There are several main vectors of scrub typhus in China, and Leptotrombidium rubellum Wang et Liao, 1984 is one of them, which was previously considered to be restricted to the coastal regions of Changle to Xiamen, Fujian province of east China. Ecological investigation of chigger mites in recent years demonstrated the presence of L. rubellum also in Yunnan province. Chigger mites were collected from 34 counties, in which 127,460 larval mites were collected from 14,381 small mammal hosts. A total of 277 species belonging to 26 genera and three subfamilies were identified. A total of 705/127,460 (0.55%) L. rubellum were collected from eight counties. Leptotrombidium rubellum was collected mainly at low elevations in southern Yunnan. A total of 663/705 (94.04%) of L. rubellum were collected from Rattus flavipectus (Milne-Edwards, 1871) found in outdoor habitats with relatively high infestation prevalence and mean intensity. Although it was collected from several hosts, the primary host was Rattus tanezumi. This represents a new distribution record of L. rubellum for Yunnan province.