Pre-erythrocytic Stage of Malaria Infection and the Molecular Targets Available for Interventions

Abstract

October 2016 | Volume 3 | Issue 4 | Page 132 M alaria remains the most important parasitic disease in humans, affecting nearly half of the human pop-ulation. Among the several Plasmodium species that cause human malaria, Plasmodium falciparum (P. falciparum) ac-counts for the majority of severe malaria and deaths, fol-lowed by Plasmodium vivax(P. vivax) (Beeson et al., 2016). Malaria parasites have both asexual (which takes place in the mammalian host), and sexual (which takes place in the anopheles mosquitoes) phases in life cycle. The erythro-cytic cycle generates male and female gametocytes which are picked up by mosquitoes during a blood meal, leading to fertilization and zygote formation within the mosqui-to stomach (Zhang et al., 2010). Motile zygote (ookinete) penetrates the midgut epithelium to form oocysts within which hundreds of sporozoites are generated. Oocysts rup-ture to release sporozoites which invade the salivary glands from where they are injected into the mammalian blood during a bite. Within minutes of sporozoites inoculation in mammalian host, rapid and efficient hepatocytes inva-sion are believed to take place (Shin et al., 1982). While in the liver cells, sporozoites multiply and differentiate into merozoites which are subsequently released to bind and invade erythrocytes (Sultan, 1999). The differentiation of a certain population of merozoites into gametocytes and subsequent uptake of male and female gametocytes by mosquitoes ensures the passage from asexual to sexual stage of Plasmodium development. Malaria intervention strategies involving the use of insec-ticide-treated-bed nets, improved access to early diagnosis and the use of highly effective Artemisinin -based com-bination therapy (ACT) has yielded tremendous results in reducing the burden of malaria globally (Beeson et al., 2016). However, despite the availability of preventive and