The Concept of Developing a Plasmodium vivax Malarial Vaccine with a Focus on its Pre-erythrocytic Stage
Human malaria is a blood infection caused by protozoal parasites
of the genus Plasmodium and is transmitted by species
of the Anopheles mosquitoes.
It is a parasitic disease that is endemic in most tropical and subtropical
regions worldwide. Four species of malarial parasites that infects
humans are, P. falciparum, P. vivax, P. malariae and P. ovale.
Plasmodium vivax, is one of the most prevalent form of
the human malarial parasites, although the mortality
rate is considerably lower than that for P. falciparum infection.
P. vivax malaria causes significant morbidity for hundreds
of millions of residents throughout Asia, Middle East,
the Western Pacific and South America.
In 2013, Plasmodium vivax alone generated a global burden of about 16
million cases annually and represents a tremendous public health
problem, particularly in the South American and Asian continents.
Plasmodium vivax parasites consists of a complex lifecycle
that includes 2 cycles: (i) the sexual cycle in the female Anopheles vector,
and (ii) the asexual cycle in the human host.
Infection with these parasites presents an asymptomatic
pre erythrocytic stage, which occurs in the liver, closely followed
by a symptomatic erythrocytic stage.
During a blood meal, when the mosquito injects its
sporozoites directly into the blood stream or into the tissues of
the host, the motile sporozoites penetrates small blood vessels
and enters the liver.
In hepatic sinusoids of the liver, they invade
healthy hepatocytes. The sporozoites differentiates into mature
schizonts in the hepatocytes with thousands of uninucleated
merozoites surrounded by a membrane (pre–erythrocytic stage).
Vaccin Res Open J. 2018; 3(1): 1-6. doi: 10.17140/VROJ-3-109
