Malaria Stratification Mapping in Thailand to Support Prevention of Re-establishment

Thailand aims to eliminate malaria by 2026, with 46 of the country’s 77 provinces already verified as malaria free. However, these provinces remain susceptible to the re-establishment of indigenous transmission that would threaten the national goal. Thus, the country is prioritizing national and subnational prevention of re-establishment (POR) planning while considering the spatial heterogeneity of the remaining malaria caseload. To support POR efforts, a novel non-modeling method produced a malaria stratification map at the tambon (subdistrict) level, incorporating malaria case data, environmental factors, and demographic data. The stratification analysis categorized 7,425 tambons into the following four risk strata: Local Transmission (2.9%), At Risk for Transmission (3.1%), High Risk for Reintroduction (2.9%), and Low Risk for Reintroduction (91.1%). The stratification map will support the national program to target malaria interventions in remaining hotspots and mitigate the risk of transmission in malaria-free areas.