Association between Plasmodium falciparum AMA-1, MSP-119, and GLURP- R2 IgG antibody responses and malaria transmission exposure in rural Tanga Region, north-eastern Tanzania

Malaria remains a significant health burden in sub-Saharan Africa despite ongoing control efforts. Antibody responses to key Plasmodium falciparum antigens— pf AMA-1, pf MSP-1₁₉, and pf GLURP-R2—serve as markers of exposure and immunity. However, data on their seasonal variation in rural settings and their relationship with malaria protection are limited. This study assessed the association between antibody levels to pf AMA-1, pf MSP-1₁₉, and pf GLURP-R2 and concurrent malaria infection in rural Tanga, northeastern Tanzania. This was a retrospective laboratory-based study analyzing 362 archived dried blood spot (DBS) samples collected during three cross-sectional surveys in rural Tanga, conducted in June 2021 (rainy season), October 2021 (dry season), and February 2022 (short rainy season). IgG responses against three P. falciparum blood-stage antigens— pf MSP-1₁₉, pf AMA-1, and pf GLURP-R2—were quantified using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using SPSS version 27.0. Antibody levels across the three surveys were compared with the Kruskal–Wallis test, followed by non-parametric pairwise comparisons. Categorical variables were analyzed using the Chi-square test, with p < 0.05 considered statistically significant. IgG responses to pf MSP-1₁₉ showed significant seasonal variation ( p < 0.0001), with the highest levels observed during the rainy season. pf AMA-1 levels also peaked during the short rainy season, reaching marginal significance ( p = 0.050), while pf GLURP-R2 levels peaked during the rainy season ( p < 0.0001). Malaria-positive individuals had significantly higher pf AMA-1 IgG levels during the short rainy season ( p = 0.02). Individuals who did not use long-lasting insecticidal nets (LLINs) exhibited higher median IgG levels for pf AMA-1 ( p < 0.0001), pf MSP-1₁₉ ( p = 0.03), and pf GLURP-R2 ( p = 0.04), particularly during the rainy season. Environmental factors such as garbage pits, stagnant water, and vegetation showed significant associations with IgG levels to pf AMA-1, pf MSP-1₁₉, and pf GLURP-R2 across different seasons ( p < 0.05). IgG responses to pf AMA-1, pf MSP-1₁₉, and pf GLURP-R2 varied seasonally and were associated with malaria infection status, LLIN use, and environmental factors. These findings support further evaluation of these antibody responses as potential complementary markers of malaria exposure and transmission.