Naturally acquired antibody response to Plasmodium falciparum describes heterogeneity in transmission on islands in Lake Victoria

Abstract

As markers of exposure anti-malaria antibody responses can help characterise heterogeneity in malaria transmission. In the present study antibody responses to Plasmodium falciparum AMA-1, MSP-119 and CSP were measured with the aim to describe transmission patterns in meso-endemic settings in Lake Victoria. Two cross-sectional surveys were conducted in Lake Victoria in January and August 2012. The study area comprised of three settings: mainland (Ungoye), large island (Mfangano) and small islands (Takawiri, Kibuogi, Ngodhe). Individuals provided a finger-blood sample to assess malaria infection by microscopy and PCR. Antibody response to P. falciparum was determined in 4,112 individuals by ELISA using eluted dried blood from filter paper. The overall seroprevalence was 64.0% for AMA-1, 39.5% for MSP-119, and 12.9% for CSP. Between settings, seroprevalences for merozoite antigens were similar between Ungoye and Mfangano, but higher when compared to the small islands. For AMA-1, the seroconversion rates (SCRs) ranged from 0.121 (Ngodhe) to 0.202 (Ungoye), and were strongly correlated to parasite prevalence. We observed heterogeneity in serological indices across study sites in Lake Victoria. These data suggest that AMA-1 and MSP-119 sero-epidemiological analysis may provide further evidence in assessing variation in malaria exposure and evaluating malaria control efforts in high endemic area.

Analysis of anti-Plasmodium IgG profiles among Fulani nomadic pastoralists in northern Senegal to assess malaria exposure

“…In other countries, Fulani populations have demonstrated higher levels of malaria antibody than sympatric populations with similar malaria exposure [24][25][26] and the relationship between high level of MSP-1 19 antibody and protection from clinical malaria has been reported [27][28][29][30][31][32]. In the present cohort, antibody responses increased significantly with age in all study areas, which is in agreement with increasing immunity over time and seen in other studies in sub-Saharan Africa, Oceania and South America [19][20][21]. Regarding gender, the prevalence of antibody response was significantly higher among males except in Ranérou, and to a lesser extent in Dagana, where higher prevalence was observed in females.…”

“…A p-value < 0.05 was considered significant. A reversible catalytic model was fit to the seropositivity by age data for each antigen, and the estimates for the serological conversion rate (SCR) and serological reversion rate (SRR) per year were directly calculated from the likelihood model [20].…”

“…These districts also have higher reported annual incidence of confirmed malaria than the other two districts, Dagana and Podor, two of the northernmost districts in Senegal [18]. However, PfMSP-1 19 seropositivity is known to increase with age [19][20][21], and positivity was dramatically lower among children under 10 years than among those 10 years and older, suggesting that those under 10 years have had less exposure to P. falciparum in the context of recent declines in transmission.…”

“…A bead coupled to GST alone was also included in the multiplex panel to assess if any individuals in the study produced IgG against GST, but no persons were found to have anti-GST IgG as defined by an assay signal above 100 MFI-bg units. For P. falciparum, peptides for the circumsporozoite protein (CSP, (NANP) × 5 sequence) and liver stage antigen 1 (LSA-1) [20] were also included. Glutathione-S-transferase (GST) from Schistosoma japonicum was included as a non-binding control antigen.…”

Blood-stage Plasmodium vivax antibody dynamics in a low transmission setting: A nine year follow-up study in the Amazon region

“…In P . falciparum studies, recent findings also confirm that AMA-1 is a useful surrogate marker in low transmission settings [ 45 ]. Additionally, our results indicate that the applicability of circulating blood-stage antibodies as serological markers for recent infection depends on the immunological background of the study population.…”