Epidemiological Profile and Surveillance Evaluation During the First Year of Malaria Elimination Status in West Java, Indonesia

Abstract

Following the achievement of sub-national malaria elimination status, provinces are required to prevent the reintroduction of indigenous transmission. West Java, one of the provinces declared malaria-free, remains at risk due to population mobility from endemic regions within Indonesia. Continuous surveillance and epidemiological monitoring are therefore essential to sustain elimination status. This study aimed to describe the epidemiological profile of malaria cases and evaluate surveillance characteristics during the first post-elimination year in West Java, Indonesia. This cross-sectional study analyzed secondary data from the Malaria Surveillance Information System from January to December 2023, validated by the West Java Provincial Health Office. All laboratory-confirmed malaria cases were included. Records with incomplete identifiers were excluded to avoid duplication, while relapse cases were defined as recurrent Plasmodium vivax infections documented in the registry. A total of 514 confirmed malaria cases were identified. Most cases occurred in adults (97.5%) and males (95.1%), predominantly military personnel (37.0%) and police officers (25.3%). Most infections were detected through passive case detection (95.5%) and managed as inpatient cases (85.2%). All cases were classified as imported malaria, defined as infections acquired outside West Java and diagnosed within the province. Microscopy was the primary diagnostic method (89.7%), and Plasmodium vivax accounted for most infections (71.8%), including several relapse cases. West Java successfully maintained zero indigenous malaria transmission in 2023. However, the predominance of imported P. vivax cases among highly mobile occupational groups highlights the continuing risk of malaria reintroduction. Strengthened surveillance, systematic screening of travelers from endemic areas, and appropriate radical cure for P. vivax are essential to sustain malaria elimination.