From Control to Elimination: Integrated Impact of Malaria Interventions in the Yunnan Province of China from 1983 to 2013

Background: Malaria remains a significant public health problem in the border areas of Yunnan Province, China. Yunnan faces an increasing risk of imported malaria cases from its border countries of Myanmar, Laos and Vietnam. Imported malaria has slowed efforts to eliminate malaria in the province. The aim of this study is to understand the past and present malaria situation in Yunnan Province and to identify the challenges involved in controlling the disease. Methods: A retrospective study was conducted of the past 30 years of surveillance data from relevant sources on malaria in Yunnan. Researchers collected data on malaria cases from 1983 to 2013 from the China Information System for Disease Control and Prevention, as well as from case investigation reports. Results: From 1983 to 2013, a total of 375,602 malaria cases were reported in Yunnan Province; 739 of these resulted in death. Of the total number of malaria cases, 72.71% were infected with Plasmodium vivax, 21.17% with P. falciparum, 0.02% with P. malariae, 1.43% with mixed infection cases, and 4.67% of untyped cases. Of the total number of reported cases, 207,956 were reported from the border 25 counties, comprising 55.4% of the total malaria cases and 44.6% (167,646) were reported from the inland counties (the other 104 counties) of the province. The malaria Prevalence rates (MPRs) decreased from 64.8 per 100,000 in 1983 to 0.9 per 100,000 in 2013, which is equal to a 98.6% reduction in the malaria burden. Among the border 25 counties, the malaria prevalence rates decreased from 179.8 per 100,000 in 1983 to 4.5 per 100,000 in 2013, which equates to a reduction of the malaria burden by 97.5%. The malaria prevalence rates in the inland counties decreased from 45.4 per 100,000 in 1983 to 0.3 per 100,000 in 2013, which equates to a reduction of the malaria burden by 99.3%. In 1983, malaria was prevalent in the northwest of Yunnan, Yuanjiang-Honghe River Valley and border areas; but it remained prevalent in the western and southern border areas of Yunnan in 2013. The population at high risk of contracting malaria is the young male farmers and migrant workers in summer and fall. An analysis of the integrated interventions showed that interventions have been effective in preventing and controlling malaria. Conclusion: From 1983 to 2013, malaria control has been effective in Yunnan Province. Malaria has almost been eliminated in the inland areas. Future control interventions should focus on the border areas.