Identification and antigenic typing of Rickettsia tsutsugamushi in naturally infected chiggers (Acarina: Trombiculidae) by direct immunofluorescence.

Rickettsia tsutsugamushi organisms were detected and typed antigenically by direct immunofluorescence in mites from laboratory-maintained infected colonies of Leptotrombidium (Leptotrombidium) fletcheri and L. (L.) arenicola. Rickettsiae were identified most readily in unengorged larvae, but were also discernable in engorged larvae and all post-larval stages of the vectors.