Antibodies to Plasmodium falciparum are specific
biomarkers that can be used to monitor parasite exposure over broader time frames than microscopy, rapid diagnostic tests, or molecular assays. Consequently, seroprevalence surveys can assist with monitoring the impact of
malaria control interventions, particularly in the final stages of elimination, when parasite incidence is low. The
protein array format to measure
antibodies to diverse P. falciparum
antigens requires only small sample volumes and is high throughput, permitting the monitoring of
malaria transmission on large spatial and temporal scales. We expanded the use of a
protein microarray to assess
malaria transmission in settings beyond those with a low
malaria incidence. Antibody responses in children and adults were profiled, using a P. falciparum
protein microarray, through community-based surveys in three areas in Zambia and Zimbabwe at different stages of
malaria control and elimination. These three epidemiological settings had distinct serological profiles reflective of their
malaria transmission histories. While there was little correlation between transmission intensity and antibody signals (magnitude or breadth) in adults, there was a clear correlation in children younger than 5 years of age.
Antibodies in adults appeared to be durable even in the absence of significant recent transmission, whereas
antibodies in children provided a more accurate picture of recent levels of transmission intensity. Seroprevalence studies in children could provide a valuable marker of progress toward
malaria elimination.IMPORTANCE As
malaria approaches elimination in many areas of the world, monitoring the effect of control measures becomes more important but challenging. Low-level
infections may go undetected by conventional tests that depend on
parasitemia, particularly in immune individuals, who typically show no symptoms of
malaria. In contrast,
antibodies persist after
parasitemia and may provide a more accurate picture of recent exposure. Only a few parasite
antigens-mainly
vaccine candidates-have been evaluated in seroepidemiological studies. We examined antibody responses to 500 different
malaria proteins in blood samples collected through community-based surveillance from areas with low, medium, and high
malaria transmission intensities. The breadth of the antibody responses in adults was broad in all three settings and was a poor correlate of recent exposure. In contrast, children represented a better sentinel population for monitoring recent
malaria transmission. These data will help inform the use of multiplex serology for
malaria surveillance.