Urogenital Schistosomiasis is associated with an increased risk of Plasmodium falciparum infection in Burkina Faso

Abstract

There is significant overlap in the global distribution of malaria and neglected tropical diseases, with the largest health burden in Sub-Saharan Africa, where areas are co-endemic for malaria and schistosomiasis, soil-transmitted helminths, or lymphatic filariasis. Some studies suggest that helminth infections may increase susceptibility to malaria, but evidence is limited. This study investigated the association between urogenital schistosomiasis and the risk of Plasmodium falciparum (P. falciparum) parasitemia in rural Burkina Faso. A cohort of 424 subjects participated in five cross-sectional malaria surveys. Active Schistosoma hematobium infection was diagnosed at baseline using plasma circulating anodic antigen detection, whereas P. falciparum infection was diagnosed at each survey via blood smear microscopy. Longitudinal analysis assessed the association between baseline urogenital schistosomiasis and P. falciparum parasitemia over time, adjusting for sex, age, village, ethnicity, and hemoglobin genotype. Subjects with active urogenital schistosomiasis had a similar to 25% increase in the cumulative incidence of P. falciparum infection (incidence rate ratio [IRR] = 1.26; 95% CI = 1.08-1.46; P = 0.004), as well as a nonsignificant trend toward higher parasite density (exponential of the b coefficient [Expb] = 1.12; 95% CI = 0.96-1.31; P = 0.133) and higher odds of infection over five surveys (odds ratio [OR] = 1.79; 95% CI = 0.89-3.59; P = 0.104). Higher intensity of schistosomiasis increased the cumulative incidence of P. falciparum (IRR = 1.12; 95% CI = 1.05-1.19; P = 0.001) and parasite density (Expb = 1.08; 95% CI = 1.01-1.15; P = 0.026), and a trend toward increased odds of infection was also observed (OR = 1.28; 95% CI = 0.91-1.80; P = 0.159). This study provides longitudinal evidence that urogenital schistosomiasis is associated with an increased risk of P. falciparum parasitaemia, highlighting the need for integrated control strategies for both diseases, particularly in school-aged children and adolescents.