Plasmodium Falciparum Reticulocyte Parasitation in Children and adults With Uncomplicated Malaria: Association With Clinical, Parasitological and Haematological Outcomes in Western Kenya

Abstract

Reticulocytosis is an imp~rtant previously unappreciated surrogate marker of recent Plasmodium Jalciparum reticulocyte parasitation. Evidence from studies in murine rand primate models show increased prevalence nf Plasmodium Jalciparum parasitisation of reticulocytes. The increase in reticulocyte infection has been attributed to compensatory reticulocytosis and increased parasite densities However, the prevalence of P. falciparum parasitisation of reticulocytes in human p~Pl-lations in holoendemic areas of malaria is unknown. Therefore, the current study examier ~the prevalence of P.falciparum parasitation ofreticulocytes and its association with clinical parasitological and haematological outcomes in children (n=164) and adults (n=41) with <::\~t.eP. falciparum malaria and healthy malaria negative controls (children, n=132 and adultr, l=60) from a holoendemic area of malaria of western Kenya. Malaria diagnosis and species identification was performed using Giemsa stained thick and thin blood smears while reticrocyte parasitation was determined using New Methylene Blue- Giemsa counter-stained thini Led films. Results of this study showed that children with malaria presented with increased lumbers of infected reticulocytes compared to adults with malaria (p=0.006; Mann- Whitne: ~j test). In addition, children with malaria presented with higher reticulocyte counts .x» apared to those without malaria (p<0.0001; Mann-Whitney U test). Dichotomization of': h ldren and adults with malaria into presence or absence of infected reticulocytes revealec 1 iat presence of infected reticulocytes was associated with higher parasite densities (p<O.O 101andp<O.OOOI;Mann- Whitney U test) and increased prevalence ofHDP (high density pan sitaemia, 2::10,000parasites/ul.) (p=O.073 and p<O.OOOI; Fisher's exact test) in both adults an I»hildren, respectively. Erythrocytic analyses revealed that increased infection of reticulocyte; in children with malaria was associated with higher reticulocyte count (p<O.OOOl; Mann if Ltney U test) and increased reticulocytosis (RPI, reticulocyte production index) (p<O.(j;lOl , Mann-Whitney U test). Correlation analysis