[Leptotrombidium (L.) scutellare as the transmitting vector of tsutsugamushi disease of autumn-winter type in Jiangsu Province].

In 1986, epidemic of tsutsugamushi disease of autumn-winter type was found in Jiangsu province. To clarify the vector of this disease, we carried out a series of studies in 1986-1992. Leptotrombidium (L.) scutellare was found to be a dominant species of chigger mite on rats in the endemic areas and its seasonal distribution was correlated with the incidence of tsutsugamushi disease in inhabitants. This mite could naturally be infected by Rickettsia tsutsugamushi, and R. tsutsugamushi could be transmitted via biting and transovarial transmission. Specific antibodies could be detected in the sera of mice bitten by the mites or inoculated with the suspension of mites. Serological typing of the sera of mice was of Gilliam type. The above results demonstrate that L. (L.) scutellare can serve as transmitting vector of tsutsugamushi disease of autumn-winter type.