• Alicia Jaramillo-Underwood, Camelia Herman, Samuel E Jean, Doug Nace, E Scott Elder, Keri Robinson, Alaine Knipes, Caitlin M Worrell, LeAnne M Fox, Luccene Desir, Carl Fayette, Alain Javel, Franck Monestime, Kimberly E Mace, Venkatachalam Udhayakumar, Kimberly Y Won, Michelle A Chang, Jean F Lemoine, and Eric Rogier.
• US Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
• Bmc Med. 2024 Jan 23; 22 (1): 3131.

BackgroundDue to low numbers of active infections and persons presenting to health facilities for malaria treatment, case-based surveillance is inefficient for understanding the remaining disease burden in low malaria transmission settings. Serological data through the detection of IgG antibodies from previous malaria parasite exposure can fill this gap by providing a nuanced picture of where sustained transmission remains. Study enrollment at sites of gathering provides a potential approach to spatially estimate malaria exposure and could preclude the need for more intensive community-based sampling.MethodsThis study compared spatial estimates of malaria exposure from cross-sectional school- and community-based sampling in Haiti. A total of 52,405 blood samples were collected from 2012 to 2017. Multiplex bead assays (MBAs) tested IgG against P. falciparum liver stage antigen-1 (LSA-1), apical membrane antigen 1 (AMA1), and merozoite surface protein 1 (MSP1). Predictive geospatial models of seropositivity adjusted for environmental covariates, and results were compared using correlations by coordinate points and communes across Haiti.ResultsConsistent directional associations were observed between seroprevalence and environmental covariates for elevation (negative), air temperature (negative), and travel time to urban centers (positive). Spearman's rank correlation for predicted seroprevalence at coordinate points was lowest for LSA-1 (ρ = 0.10, 95% CI: 0.09-0.11), but improved for AMA1 (ρ = 0.36, 95% CI: 0.35-0.37) and MSP1 (ρ = 0.48, 95% CI: 0.47-0.49).ConclusionsIn settings approaching P. falciparum elimination, case-based prevalence data does not provide a resolution of ongoing malaria transmission in the population. Immunogenic antigen targets (e.g., AMA1, MSP1) that give higher population rates of seropositivity provide moderate correlation to gold standard community sampling designs and are a feasible approach to discern foci of residual P. falciparum transmission in an area.© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

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