Demonstration of the natural foci of tsutsugamushi disease in Nan Peng Lie Islands in China.

In recent years, the incidence of tsutsugamushi disease has increased in Nan Peng Lie Islands in China, and the disease has not been recorded in this region. The natural foci of tsutsugamushi disease were investigated in this paper. Isolation of Orientia tsutsugamushi and the study of preventive measures were also performed. The region was the island natural foci of south subtropical zone. The main host and vector were Rattus norvegicus and Leptotrombidium (L.) deliens respectively. The seasonal quantity trends of Rattus norvegicus and Leptotrombidium (L.) deliense were consistent with the incidence of human infection in the region. The strains of O. tsutsugamushi were isolated from Rattus norvegicus and Leptotrombidium (L.) deliense. The identification showed that most strains were Karp. The seroepidemiology showed a high prevalence of antibody against O. tsutsugamushi. After preventive measures were implemented, the incidence was descent. So Nan Peng Lie Islands were the natural foci of tsutsugamushi disease.