Malaria Infection in Patients with Sickle Cell Disease in Nigeria: Association with Markers of Hyposplenism

Background Malaria is considered an important cause of morbidity and mortality among people living with sickle cell disease (SCD). This has partly been attributed to the loss of splenic function that occurs early in the disease process. We aimed to study the prevalence of malaria infection among Nigerian SCD patients and explore the association with spleen size and function. Method This was a hospital-based, cross-sectional study performed at the University of Maiduguri Teaching Hospital in North-Eastern Nigeria from October 2020 to November 2021. Giemsa-stained blood smears for malaria parasites, Howell-Jolly body (HJB) red cells enumeration for spleen function evaluation and ultrasonography for spleen size assessment, were performed in acutely-ill SCD patients. Results of malaria parasitaemia and parasite density were compared with those of steady-state SCD patients and non-SCD controls. Results A total of 394 participants consisting of 119 acutely-ill SCD patients, 167 steady-state SCD controls and 108 non-SCD controls were studied. The prevalence of P. falciparum parasitaemia was 51.3% in acutely-ill SCD patients, 31.7% in steady-state SCD controls and 13.0% in the non-SCD controls. In the SCD group, the mean parasite density was significantly higher among the acutely-ill SCD patients than the steady-state SCD controls (29,747 vs 18,563 parasites / ul; P = 0 . 001 ). Although parasitaemia prevalence was lower among the non-SCD controls, parasite density was significantly higher compared to both SCD groups ( P = 0 . 0001 ). Among the acutely-ill SCD patients, the prevalence of clinical malaria and severe malaria anaemia were highest among children less than 5 years of age. Prevalence of parasitaemia ( P = 0 . 540 ) and parasite density ( P = 0 . 975 ) among acutely-ill SCD patients with visualized spleens on ultrasonography were not statistically different compared to those with absent spleens. Similarly, the frequency of HJB red cells among patients with parasitaemia was not significantly different compared to patients without parasitaemia ( P = 0 . 183 ). Conclusion Our study highlights the frequency and role of malaria infection in acutely-ill SCD patients, especially in those younger than five years. Although we have found no evidence of an increased risk of malaria parasitaemia or parasite density with markers of hyposplenism, the role played by an underlying immunity to malaria among SCD patients is not clear. Further studies are required to elucidate the role of hyposplenism and malaria in SCD patients in malaria-endemic regions.