RESUMEN
BACKGROUND: The continuous monitoring of malaria transmission intensity is still required to maintain elimination status after reaching the malaria elimination stage. In this study, serological surveillance with multiepitope artificial antigen was used to assess the transmission of Plasmodium falciparum in Yunnan, China, where malaria elimination has just been achieved, to provide data to support malaria control in the postelimination period. METHODS: Samples were collected in three border counties and one inland county in Yunnan Province in 2016 using a stratified whole-group sampling method. Fingerstick blood was collected from all participants, and antibodies to Malaria Random Constructed Antigen-1 (M. RCAg-1) were detected by indirect ELISA. The transmission intensity of P. falciparum malaria was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR). RESULTS: A total of 5566 samples were collected. There was no statistically significant difference in antibody level between the inland county and the nonendemic area, but the antibody level in border counties was significantly higher than those in the inland county and the nonendemic control area. No seropositive cases were found in Yanjin County, and the seropositivity rate increased with age in the three border counties. The highest intensity of P. falciparum malaria transmission was in Zhenkang County (SCR = 0.0030, CI: 0.0029, 0.0031), followed by Gengma County (SCR = 0.0013, CI: 0.0012, 0.0015) and Yingjiang County (SCR = 0.00088, CI: 0.00083, 0.00090). CONCLUSION: The transmission intensity of P. falciparum malaria in Yunnan Province has obviously decreased in recent years, but for the border areas where malaria has just been eliminated, the transmission intensity will not immediately drop to zero, and it still needs to be monitored for a period of time to maintain malaria elimination status.