Exposure To Mosquito Bites And Stage-Specific Antibody Responses Against Plasmodium Falciparum In Two Communities In Southern Ghana

Abstract

Immunity is gained through repetitive exposure to malaria, which differs greatly based on the severity of the infection and environmental factors. In today’s research, a measure of Anopheles gambiae bite exposure has become fundamental for malaria endemic area identification, malaria risk prediction, and determination of the dynamics of malaria prevalence and reoccurrence in communities. This study aimed at investigating whether increased exposure to Anopheles mosquito bites in afebrile individuals enhances gametocyte production and subsequently antibody responses against Plasmodium falciparum gametocytes. Participants aged between 3 and 70 years were recruited from two communities, Simiw and Obom. Whole blood (1 ml) was collected from participants in Simiw (December 2019) and Obom (January 2020). Aliquots of blood were used to prepare dried blood spots for P falciparum identification by PCR. IgG antibodies against gSG6-P1 and P. falciparum antigens were quantified from plasma using indirect ELISA. Antibodies (IgG) against gSG6-P1 for individuals with the age groups 10-15 years for both Simiw and Obom showed a significant difference (p0.0001) with participants in Simiw recording higher median (95%CI) antibody concentration (2.980 (3.077-3.662) ng/ml) than those in Obom (2.088 (2.176-2.602) ng/ml). Individuals from Obom within the age group 10-15 years had higher anti-Pfs230 antibody levels (6591 (1210551-4984924) ng/ml) compared to individuals from Simiw with age group 0-9 years (4707 (5874-10446) ng/ml) (p=0.0008). The higher exposure of participants from simw to mosquito bites were mostly from uninfected mosquitoes as anti-PfCSP IgG antibody titres were found to be relatively lower in Simiw compared to Obom.