Surveillance of risk factors from imported cases of falciparum malaria in Sichuan, China.

With a sharp increase of the number of imported cases of falciparum malaria, the potential risk of the reemergent transmission of this kind of malaria is approaching imminently in Sichuan Province, China, where falciparum malaria had completely been eliminated by the 1960s. It has been of concern whether the epidemic would appear again, because there still exist malaria vectors and vulnerable populations in Sichuan. By undertaking surveillance on 31 cases returning from the endemic areas with falciparum malaria, and on their family members and neighbors, we have not found out any introduced case of falciparum malaria who was contracted from the imported ones. The vector monitoring results suggested that the use of insecticide-impregnated bednets interfered with malaria vectorial capacity and expectation of infective life. The epidemiological characteristics of the imported cases and reasons why no consequent malaria case was detected were analysed at dynastic level in detail.