Spatiotemporal heterogeneity in malaria transmission across Indonesia: analysis of routine surveillance data 2010-2019.

Abstract

Background: Indonesia faces challenges in achieving its goal of eliminating malaria by 2030, with cases stagnating between 2015 and 2019. This study analysed regional epidemiological trends and demographic changes in malaria cases from 2010 to 2019, considering differences in surveillance across the country.

Methods: We analysed national and sub-national malaria routine surveillance data using generalised additive and generalised linear models to assess temporal trends in case reporting, test positivity, demographics, and parasite species distribution while accounting for surveillance variations.

Results: After adjusting for increased testing from 2015 onwards, we estimated declining malaria incidence in six of seven Indonesian regions. These regions showed a demographic shift toward older, predominantly male cases, suggesting a transition from household to occupational transmission. In contrast, Papua maintained high transmission with cases concentrated in children. Despite comprising only 2% of Indonesia's population, Papua's contribution to national malaria cases rose from 40 to 90% (2010-2019).

Conclusion: While most Indonesian regions progress toward elimination by addressing mobile and migrant populations and P. vivax transmission, Papua shows different patterns with persistently high transmission among children. Achieving nationwide elimination requires enhanced control measures, improved healthcare access, and strengthened multisectoral collaboration to address these region-specific challenges.