Malaria from hyperendemicity to elimination along international borders in Yunnan, China during 2003‒2020: a case study

Background: Border malaria is one of the most intractable problems hindering malaria elimination worldwide.Movement of both the human population and anopheline mosquitoes infected with Plasmodium spp.can cause cross-border malaria transmission.The Yunnan border area was still hyperendemic for malaria in the early part of this century.The objective of this case study was to analyze the strategies,interventions and impacts of malaria control and elimination in the Yunnan border area.Main text: A total of 10,349 malaria cases and 17.1 per 10,000 person-years of annual parasite incidence(API)were reported in the border area in 2003.Based on natural village-based stratification,integrated interventions,including mass drug administration for radical cures and preventive treatment,clinically presumptive treatment of all febrile patients for malaria and indoor residual spraying or dipping bed nets with insecticides were successfully carried out from 2003 to 2013.The overall API was reduced to 0.6 per 10,000 person-years by 2013,while effective cross-border collaboration interventions dramatically reduced the malaria burden in the neighbouring border areas of Myanmar.From 2014 forward,the comprehensive strategy,including universal coverage of surveillance to detect malaria cases,a rapid response to possible malaria cases and effective border collaboration with neighbouring areas,successfully eliminated malaria and prevented reintroduction of malaria transmission in the Yunnan border area.Conclusions: In Yunnan malaria burden has successfully reduced by dynamically accurate stratification and comprehensive interventions;and then the region achieved elimination and prevented reintroduction of malaria transmission through intensive surveillance,rapid response and border collaboration.Other border areas should perform their own intervention trials to develop their own effective strategy.