About Malaria

What is Malaria?


sporozoites, merozoites, mosquito, Plasmodium, liver, blood cells, Anopheles, parasite, salivary glands, hepatocytes, malaria, gametocytes, species, trasmission, infection.

Malaria is a parasitosis caused by protozoa of the genus Plasmodium.

Among the various species of Plasmodium parasite (Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and, Plasmodium malariae), the most common and dangerous are Plasmodium falciparum and Plasmodium vivax, causing the highest mortality rate among infected individuals.

The vector of the parasite is the mosquito of the genus Anopheles.

Malaria infection starts when a female Anopheles mosquito bites a human host releasing Plasmodium sporozoites into the human body.

Sporozoites actively reach peripheral circulation and migrate to the liver invading hepatocytes, in which occurs a first stage of replication of the parasite (Amino et al., 2006; Prudêncio et al., 2006).

During replication in liver cells, sporozoites produce merozoites that are released into the blood stream.

Merozoites invade red blood cells where occurs a second stage of replication of the parasite (Sturm et al., 2006).

They undergo various stages of maturation before forming new merozoites that infect other erythrocytes, when the first ones undergo lysis.

A small amount of merozoites develop into sexual stages called gametocytes that reach the dermis where they are taken up by another mosquito.

In the midgut of the new mosquito, gametocytes differentiate into male and female gametes which, after fertilization and sporogonic development, form new infectious sporozoites which reach the salivary glands of the mosquito for transmission into another host (Josling et al., 2015; Bancells et al., 2019).


  1. Amino, R., Thiberge, S., Martin, B., Celli, S., Shorte, S., Frischknecht, F., et al. (2006) Quantitative imaging of Plasmodium transmission from mosquito to mammal. Nat Med. 12, 220-4 
  2. Bancells, C., Llorà-Batlle, O., Poran, A., Nötzel, C., Rovira-Graells, N., Elemento, O., et al. (2019) Revisiting the initial steps of sexual development in the malaria parasite Plasmodiumfalciparum. Nat Microbiol. 4, 144-54
  3. Josling, G.A., Llinás, M. (2015) Sexual development in Plasmodium parasites: knowing when it’s time to commit. Nat Rev Microbiol. 13, 573-87
  4. Prudêncio, M., Rodriguez, A., Mota, M.M. (2006) The silent path to thousands of merozoites: the Plasmodium liver stage. Nat Rev Microbiol. 4, 849-56 
  5. Sturm, A., Amino, R., van de Sand, C., Regen, T., Retzlaff, S., Rennenberg, A., et al. (2006) Manipulation of host hepatocytes by the malaria parasite for delivery into liver sinusoids. Science. 313, 1287-90