this is for an essay on malaria
so please answer ASAP!!!
-x0x- The most important part of the body's immune system is the epidermis (skin). Malaria is carried by insects, namely mosquitoes, and is traansferred directly into the blood stream. The bacteria multiplies within the red blood cells. hey-- I don't know...but I do have something you could add to your essay. People with Sickle Cell Anemia don;t get malaria. This is a reason that Sickle Cell rates increase in Africa-- Malaria kills ....but those who have sickle cell don't get it. Try this site for more info: http://sickle.bwh.harvard.edu/malaria_si...
it says: The plasmodium parasite that causes malaria is transmitted from mosquitos to men. The parasites spend part of their life cycle in the mosquito and part of it in the human host (Figure 1). The infective plasmodial sporozoites enter the bloodstream from the saliva of the feeding female anopheles mosquito. The Kupfer cells of the liver clear the sporozoites from the blood stream and kill many of the organisms. A fraction of the sporozoites escape destruction however, and penetrate the hepatocytes where they take up residence.
The parasites within the hepatocytes transform into a new entity called schizonts. The nuclear genetic material in the schizonts replicates to the point that the hepatocytes are totally filled with new forms called merozoites. A single schizont can produce thousands of merozoites. Erumpent hepatocytes release the merozoites into the bloodstream where they invade circulating red cells. After penetrating the red cells the merozoites assume a ring form called trophozoites. These organisms consume hemoglobin in erythrocytes and enlarge until they fill the cell completely. During their growth, the trophozoites metamorph into schizonts and produce new merozoites inside the red cells. The red cells subsequently lyse and release merozoites that can penetrate new red cells and restart the pernicious process.
Some of the trophozoites in the red cells take a different developmental pathway and form gametocytes. Gametocytes are the sexual form of the parasite and do no lyse the red cells. A mosquito taking a blood meal from a person whose red cells contain gametocytes acquires the malarial parasite. The sexual reproduction cycyle then begins in the mosquito. The mosquito subsequently transmits the parasite when it attacks another human host.
Malaria Defenses
The complex nature of the malaria parasite life cycle in the human host presents several points at which the organism could be targeted for destruction. The sporozoites injected into the blood stream with the initial mosquito bite are attacked there by components of the immune system. These include antibodies, lymphocytes called "natural killer cells" as well as lymphocytes that attack the malarial parasites because of prior exposure to the organisms (conditioned lymphocytes).
Host immunity is crucial to survival of people infected with the malaria parasite. This is particularly true with respect to the nocuous falciparum parasite. The immune system works best when it has been primed against the invader. Children who suffer their first or second bout of malaria have not developed the immune response needed to provide adequate defense against the parasite. This explains in part the high mortality seen in children infected with P. falciparum. Vaccines are a common way of achieving host immunity prior to pathogen exposure. Polio immunization is a well-known example. Unfortunately, the malarial parasite constantly changes its immune makeup, thereby frustrating efforts to produce an effective vaccine.
check out the site for more info.
Pattie
family website: http://www.shwachman.50megs.com | 