Lifecycle
Lifecycle
The complex lifecycle of the malaria parasite is presented the diagram below. The lifecycle of the Plasmodium species undergoes both asexual and sexual phases. When an infected female Anopheles mosquito feeds on the human host, it injects the sporozoites from its salivary glands into the blood. These sporozoites then travel to the host liver via the bloodstream and invade the liver cells. Notably, P. vivax and P. ovaleform dormant stages known as hypnozoites in the liver that cause relapsing malaria symptoms years after initial infection. Within the liver cells, sporozoites mature to schizonts. The schizonts are then released into the bloodstream as merozoites and produce symptomatic infection as they invade and destroy the red blood cells. Upon invasion of the red blood cells merozoites mature to the ring, trophozoite, and schizont asexual stages. Schizonts destroy red blood cells upon maturation and release the more of merozoites, which invade uninfected red blood cells.
Upon invasion of red blood some parasites differentiate to gametocytes – the sexual phase of the life cycle. Whengametocytes are taken up by the mosquito the male gametocyte loses its flagellum, producing male gametes. A zygote is produced when the male gamete fertilizes the female gamete. The zygote invades the gut of the mosquito and develops into an oocyst. Mature oocysts produce sporozoites that can then migrate to the salivary gland of the mosquito and repeat the cycle(1).
fig 2.1
1. Engleberg, N.C., Dermody T., DiRita, V. (2007) Schaechter’s Mechanisms of microbial disease. 492-518
fig 2.1 Animated Lifecycle of the Malaria Parasite, Power point slide, Medicines for Malaria Venture, accessed 2 October 2012,
< http://www.mmv.org/about-us/malaria-and-medicines/parasite-lifecycle
fig 2.1 Animated Lifecycle of the Malaria Parasite, Power point slide, Medicines for Malaria Venture, accessed 2 October 2012,
< http://www.mmv.org/about-us/malaria-and-medicines/parasite-lifecycle