Analysis of malaria epidemic situation before and after malaria elimination in Qiandongnan Prefecture of Guizhou / 中华地方病学杂志

ABSTRACT

Objective:To analyze the characteristics of malaria epidemic situation before and after malaria elimination in Qiandongnan Prefecture, and to provide the basis for establishment of effective strategies and measures to consolidate the achievements of malaria prevention and control.Methods:The data of malaria cases in 16 counties (cities) of Qiandongnan Prefecture from 2005 to 2018 were collected, and descriptive epidemiological method was used to analyze the infection rate of Plasmodium among local residents and floating population before (2005-2011) and after (2012-2018) elimination of malaria, and the characteristics of population distribution, seasonal distribution, species of Plasmodium and types of malaria vectors were analyzed. Results:Before elimination of malaria, total of 1 412 cases of malaria were reported, among those cases, 1 361 cases were local cases, accounting for 96.39% of the total cases. After elimination of malaria, total of 17 cases were reported, all of them were imported cases. After comparison of malaria cases before and after the elimination, the proportion of people aged from 18 to 60 was 70.54% (996/1 412) before the elimination, all 17 imported cases were 18-60 years old after the elimination, and the proportion of children/students decreased from 24.65% (348/1 412) before the elimination to 0 after the elimination. The peak incidence of malaria cases before the elimination was from June to October, and cases occurred every month. After the elimination, the imported cases were sporadic. Plasmodium vivax was the main species of Plasmodium before the elimination (98.58%, 1 392/1 412), and Plasmodium falciparum was mainly imported after the elimination (70.59%, 12/17). Before and after the elimination, Anopheles sinensis, the malaria vector, was the dominant population, but no distribution of Anopheles minimus and Anopheles anthropophagus was found after 2015. Conclusions:After the elimination of malaria in Qiandongnan Prefecture, there is a risk of local malaria cases caused by imported cases. It is suggested that local authorities should focus on the treatment of suspected malaria cases and vector surveillance of overseas returnees in the future.