Operational applications of serology for malaria surveillance in different transmission settings in Indonesia

Serological surveillance involves the detection of Plasmodium species-specific antibodies as biomarkers for monitoring recent and historical malaria transmission dynamics at population-level. These methods are particularly useful in low transmission settings where standard surveillance such as parasitological and entomological approaches are inefficient. This thesis explores the use of serological surveillance to estimate the magnitude and heterogeneity of malaria transmission using different sampling strategies, mapping techniques and serological assays in three areas of differing endemicity in Indonesia. Findings suggest that: 1) Analysis of community-based serological data can confirm the discontinuation of transmission and be used to identify high-risk areas where malaria is most likely to be reintroduced, 2) Mobile technology-based participatory mapping approaches can be used to quickly obtain spatial residential information for individuals presenting at health facilities in resource poor areas where formal addresses are typically not used and internet connectivity is limited, 3) the combination of facility-based sampling, multiplex serological assays and participatory mapping can be used as an additional surveillance method to better identify and target areas still receptive to malaria in very low transmission area conducting elimination, 4) seropositivity to Etramp5.Ag1 is sensitive and specific in predicting Plasmodium falciparum PCR positivity in children in a high transmission setting, suggesting its potential use as a marker of recent exposure in elimination setting. In conclusion, this thesis demonstrates the various applications of serological surveillance at different levels of malaria endemicity. Further implementation research is needed to enable the integration of these methods to the existing surveillance systems.