Malaria is a life-threatening infectious disease caused by the parasites of the genus Plasmodium. This disease has been afflicting numerous human lives since ages and has a profound effect on human health and longevity making it one of the most serious and threatening maladies. The protozoan parasites are transmitted mainly by the bite of a female mosquito belonging to the Anopheles genus. Subsequent to the blood meal is the transmission of sporozoites that represent the infective and motile stages of the pathogen. These sporozoites traverse through the skin to reach the liver hepatocytes via the lymphatic system.
The hepatocytes harbor these infective Plasmodia wherein they multiply to give rise to thousands of merozoites (as a result of asexual fission/schizogony) which ultimately disseminate into the bloodstream. Inside the erythrocytes, these merozoites undergo erythrocytic schizogony to replicate. Some merozoites differentiate into mature male or female gametocytes and are responsible for infecting the vector mosquito when it sucks a blood meal. (Baker 2010) The inception of clinical symptoms usually occurs 7-10 days post initial mosquito bite. Relapse of symptoms can occur for dormant forms of P.
vivax and P. ovale (hypnozoites) which can emerge in liver several years post initial exposure to mosquito merozoites if the condition is improperly treated. (White 2011) The severity of the outcome of infection depends on many host factors mainly host immunity.
The level of immunity is a direct correlate of past parasite exposure. Depending on the manifestation of disease symptoms the disease can be classified as asymptomatic, uncomplicated or severe. (Wassmer, Taylor et al. 2015) Asymptomatic malaria is caused by almost all species of Plasmodium and the infected person normally manifests no symptoms. In uncomplicated cases, the infected person exhibits moderate and non-specific symptoms such as fever, chills, diarrhea, sweating, nausea etc. The severe cases are usually due to infection with P.
falciparum (less frequently by P. vivax and P. knowlesi). The severe form of malaria is accompanied by many life-threatening complications and the symptoms include severe anemia, organ failure, cerebral malaria, coma, hypoglycemia, kidney injury and edema.
(Wassmer and Grau 2017) The outcome of this form of malaria is often fatal. Placental malaria is yet another manifestation of malaria disease which results in a poor outcome for the fetus. Regardless of the type of malaria, the characteristic symptoms are low-grade fever, chills, digestive problems and muscular aches. The onset of symptoms is sudden which gradually culminates into sweating, fever and exhaustion. The paroxysmal or sudden onset is due to the rupture of infected RBCs. The disease complications are mainly attributed to the microvascular obstruction posed by parasite-infected RBCs. (Bernabeu and Smith 2016)