The cycle of malaria parasite is in sequence of -
Schizogony in the Human Host: Man is the intermediate host for malaria, wherein the asexual phase of the life cycle occurs. The sporozoites inoculated by the infested mosquito initiate this phase of the cycle from the liver, and the latter pa continues within the red blood cells, which results in the various clinical manifestations of the disease. Pre-erythrocytic Phase - Schizogony in the Liver: With the mosquito bite, tens to a few hundred invasive sporozoites are introduced into the skin. Following the intradermal deposition, some sporozoites are destroyed by the local macrophages, some enter the lymphatics, and some others find a blood vessel. The sporozoites that enter a lymphatic vessel reach the draining lymph node wherein some of the sporozoites paially develop into exoerythrocytic stages and may also prime the T cells to mount a protective immune response. The sporozoites that find a blood vessel reach the liver within a few hours. It has recently been shown that the sporozoites travel by a continuous sequence of stick-and-slip motility, using the thrombospondin-related anonymous protein (TRAP) family and an actin-myosin motor. The sporozoites then negotiate through the liver sinusoids, and migrate into a few hepatocytes, and then multiply and grow within parasitophorous vacuoles. Each sporozoite develop into a schizont containing 10,000-30,000 merozoites (or more in case of P. falciparum). The growth and development of the parasite in the liver cells is facilitated by a a orable environment created by the The circumsporozoite protein of the parasite. The entire pre-eryhrocytic phase lasts about 5-16 days depending on the parasite species: on an average 5-6 days for P. falciparum, 8 days for P. vivax, 9 days for P. ovale, 13 days for P. malariae and 8-9 days for P. knowlesi. The pre-erythrocytic phase remains a "silent" phase, with little pathology and no symptoms, as only a few hepatocytes are affected. This phase is also a single cycle, unlike the next, erythrocytic stage, which occurs repeatedly.
1,2,3,4
1,3,2,4
1,4,2,3
1,4,3,2
parasitology