Implementation and application of a multiplex assay to detect malaria-specific antibodies: a promising tool for assessing malaria transmission in Southeast Asian pre-elimination areas

International audienceBackground: Epidemiological surveillance is a key activity in malaria control and elimination in low‑transmission and pre‑elimination settings. Hence, sensitive tools for estimating malaria force of infection are crucial. Serological mark‑ ers might provide additional information in estimating force of infection in low‑endemic areas along with classical parasite detection methods. Serological markers can be used to estimate recent, past or present malaria exposure, depending on the used markers and their half‑life. Methods: An assay based on 14 Plasmodium‑specific peptides, one peptide specific for Anopheles gambiae saliva protein and five Plasmodium‑specific recombinant proteins was developed for the MAGPIX system, assessed for its performance, and applied on blood spots from 2000 individuals collected in the Ratanakiri Province, Cambodia. Results: A significant correlation for the use of 1000 and 2000 beads/antigen/well as well as for the monoplex versus multiplex assay was observed for all antigens (p < 0.05). For the majority of antigens, antigen‑coupled beads were stable for at least 2 months. The assay was very reproducible with limited intercoupling, interplate and intraplate vari‑ ability (mean RSD