Influence of ABO Blood Groups on Plasmodium falciparum Parasitaemia and Malaria Clinical Types in Outpatients in a Government Hospital of Douala, Cameroon

Falciparum malaria is a major cause of morbidity and mortality worldwide. Plasmodium infected patients carry a wide range of parasitic loads and exhibit asymptomatic, mild or severe malaria. Among host intrinsic factors which likely influence development of malaria type, controversies remain on the relationship between malaria infection and ABO blood groups types. This cross-sectional study was designed to investigate any relationship between ABO blood types, Plasmodium loads and clinical type of malaria among outpatients received in Bonassama hospital. Each outpatient who volunteered for the study was examined, tested for ABO blood types and malaria parasites carriage. Data were statistically analyzed for any association. Of 375 Plasmodium falciparum infected patients included, ABO blood group frequency was 45.3% (O), 25.3% (A), 21.6% (B), 7.8% (AB). All ABO blood groups harboured predominantly light intensities of falciparum infections; however high intensities of infections were significantly frequent in blood group A. Gender did not significantly influence P. falciparum infection prevalence. Infection prevalence was significantly high in less than 15 years blood group A patients. P. falciparum infection prevalence was not significantly different among blood group patients (p>0.05). Although all ABO blood group patients exhibit different clinical malaria types, severe-like malaria symptoms were exhibited more frequently among blood group A and group B patients. Blood group O patients exhibited predominantly asymptomatic and uncomplicated malaria. No significant association was found between Plasmodium loads, gender and age groups. Under five year blood groups A and B patients were likely more affected by severe malaria whereas blood group O patients suffered predominantly from mild and symptomless malaria. Findings from this study demonstrated that in Douala, young blood group A and B patients were more predisposed to high intensities of P. falciparum infections and severe malaria whereas blood group O exhibited mostly light infections associated to mild and asymptomatic malaria.