Abstract
Malaria along the Thailand-Myanmar border (TMB) displays geographical heterogeneity and is characterized by high prevalence of submicroscopic carriage and the emergence artemisinin resistance in P. falciparum. Timely identification and elimination of remaining P. falciparum transmission “hotspots” is essential to contain artemisinine resistance. The aim of this study was to address the relevance of using serological biomarkers of human exposure to anopheles bites (gSG6-P1) and Plasmodium antigens to identify remaining sources of transmission and to measure spatial and temporal changes in human vector contact along the TMB. Blood spots were collected in filter papers among a cohort of 2600 people followed every 3 months up to 18 months, and used for analysis by enzyme-linked immunosorbent assay (ELISA). Our findings showed that the levels of IgG responses to gSG6-P1 antigen varied according to village, season, and age and were positively associated with the abundance of total Anopheles species and primary malaria vectors. A significant and positive association was noted between the Antibody response to gSG6-P1 and the entomological inoculation rate (EIR) hence demonstrating that heterogeneity in malaria transmission was directly associated with heterogeneous biting behavior. Further investigations showed that salivary biomarker was relevant to detect small scale variations in P. falciparum malaria. This was supported by scan statistics showing that P. falciparum clusters partially overlap the gSG6-P1 clusters. Altogether, these findings indicates Anopheles salivary biomarker as great potential for epidemiological studies and could be useful to guide the implementation of hotspot–targeted vector control interventions with the aim to achieve malaria elimination.