ABO and Rhesus Blood Group Distribution and Their Association with Plasmodium falciparum Malaria Among Patients in Yenagoa, Bayelsa State, Nigeria

ABO/Rhesus blood group systems have been proposed as host biological factors influencing susceptibility to Plasmodium falciparum malaria infection and parasite species distribution. However, evidence from the Niger Delta region of Nigeria remains limited. This study evaluated ABO/Rhesus blood group distribution, their association with malaria prevalence and Plasmodium species distribution among patients in Yenagoa, Bayelsa State. A cross-sectional study was conducted between April 2025 and March 2026 in two healthcare facilities in Yenagoa. A total of 350 participants were enrolled. Malaria diagnosis was performed by light microscopy and Rapid Diagnostic Test (RDT). ABO/Rhesus blood grouping were performed using the standard agglutination method. Plasmodium species were identified by nested PCR in 40 randomly selected confirmed-positive samples. Chi-square tests were used to assess associations, with p < 0.05 as the significance threshold. Blood group O recorded the highest malaria positivity by both microscopy (40.48%) and RDT (58.82%), while blood group AB recorded the lowest. Despite these trends, no significant association was found between ABO blood group and malaria prevalence by microscopy (χ² = 14.618, p = 0.087) or RDT (χ² = 12.224, p = 0.063). Molecular analysis of 40 samples confirmed P. falciparum in 100% and P. vivax co-infections in 27.50% (χ² = 5.517, p = 0.138). Blood group O showed higher malaria infection frequency; no significant associations were established between ABO/Rhesus blood group and malaria prevalence or species distribution in this population. This information offer vital data for local transmission dynamics and provide clinical information for surveillance in the Niger Delta region.