Malaria and Plasmodium


Title: Malaria
Author: Sorphorn Ear
Date: May 18, 2010


ABTRACT

This research paper will give a brief overview of the bacterial disease called malaria caused by Plasmodium vivax also known as Apicomplexa. This disease’s found in all ages if they were bitten by Anopheles mosquito. In this case, Plasmodium grows by sexual reproduction because Anopheles mosquito carries the infective stage of Plasmodium called sporozoite. This paper will discuss the life cycle of the malaria parasite exploration of drug resistance test, the causes, and the symptoms.

mosquito-anatomy.gif


INTRODUCTION

The malaria parasite normally found in the liver, which it can sexually reproduce and multiply to infect red blood cell. Malaria is a disease that caused by Apicomplexan, the life cycle of Plasmodium vivax is very complex so it is very hard to develop the vaccination to go against it. “Asexual reproduction (schizogony) of the parasite takes place in the liver and in the red blood cells of a human host. Sexual reproduction occurs in the intestine of an Anopheles mosquito after the mosquito has ingested gametocytes.” (Gerard et al., 348).

**The lifecycle of malaria**M.jpg
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DISCUSSION


Reproduction process
Plasmodium grows by sexual reproduction in the Anopheles mosquito. Anopheles mosquito carry infective stage of Plasmodium, called sporozoite; this can injected into human when got bite by mosquitoes. Sporozoite undergo schizogony in liver cells & produce thousands of progeny called merozoites that infect red blood cells.

Asexual reproduction
1) Infected mosquito bites human; sporozoites migrate through bloodstream to liver of human.
2) Sporozoites undergo schizogony in liver cell; merozoites are produced.
3) Merozoites released into bloodstream from liver may infect new red blood cells.
4) Merozoite develops into ring stage in the red blood cell.
5) Ring stage grows and divides, producing merozoites.
6) Merozoites are released when red blood cell ruptures; some merozoites infect new red blood cells, and some develop into male and female gametocytes.

Sexual reproduction
7) Another mosquitoes bites infected human and ingests gametocytes.
8) In mosquito’s digestive tract, gametocytes unite to form zygote.
9) resulting sporozoites migrate to salivary glands of mosquito.

Upon the release of the merozoites, their waste product, which cause fever and chills. Malaria diagnosed by microscopic observation of thick blood smears for the presence of Plasmodium (Gerard et al., 349).

external image Immature_and_mature_trophozoites_of_the_Plasmodium_vivax_parasite_PHIL_2720_lores.jpg
http://upload.wikimedia.org/wikipedia/commons/f/f2/Immature_and_mature_trophozoites_of_the_Plasmodium_vivax_parasite_PHIL_2720_lores.jpg

Symptom
Malaria can be identify, if a person is ever reach 40°C and sweating without any reasons. The other symptoms such as vomiting, headache, chills, joint weakness, diarrhea joint pain, nausea, and poor appetite. The symptom usually occur 10 days to 4 weeks after the infection.

Cause
Malaria is caused by parasite that is transmitted from one human to another by the bite of infected Anopheles mosquitoes. Mosquitoes carries germs from infected persons, dirty water, cold, wet weather or change in weather, dirty, cold or raw food, and dirty unboiled drinking water. After human got bite by infected mosquitoes, the parasites called sporozoites travel through the liver, where they mature and release another form, which is the merozoites. Merozoites enter the bloodstream and infect the red blood cells.

Treatment
Chloroquine is a frequently used anti-malarial medication. Some other medicines are quinidine, doxycycline, tetracycline, larone, or artesunate. The choice of medication depends in part on where you were when you were infected.

Some of the drugs to treat malaria such as chloroquine, atovaquone, and proquanil; require users to be cautioned about possible side effects, which include hallucinations (Gerard et al., 664).


external image mosquito_malaria.jpg



Many merozoites got released after infected red blood cells within a few seconds to renew the cycle in the blood stream. If only 1% of the red blood cells contain parasites, the estimation 100, 000, 000, 000 parasites will be in circulation at one time in a typical malaria patients. The malaria parasites have four distinctive stages. The sporozoite stage is primary interest as a target for vaccine because neutralizing it would prevent the initial infection from becoming well established. In these stages it has as many as 7000 genes that can mutate. The result is that the parasite is very efficient at evading the human immune response. The current goal is to have a vaccine by 2015 that is at least 50% effective and lasts longer than a year…by 2025, to have one that is 80% effective and lasts more than 4 years (Gerard et al., 664).
external image 23a.ht1.jpg

http://www.google.com/imgres

Malaria risk: areas where malaria is endemic, with moderate to high transmission risk (shown in red), or sporadic and unstable, with low transmission risk (shown in pink). On 26 May, five infants aged 5–17 months were inoculated with GlaxoSmithKline (GSK)'s RTS,S vaccine. In the coming months, the study will become the largest ever trial of a malaria vaccine candidate, involving 16,000 children under the age of two at eleven sites in seven African countries. Investigators hope that the phase III trials will show that RTS,S prevents at least half of the infants and young children who are vaccinated from developing the symptoms of malaria, and that the protection will last for several years. Even a partially effective vaccine is sorely needed. Most of the one million people killed every year by malaria are children under the age of 5 in sub-Saharan Africa, the World Health Organization says. "This vaccine has the potential to save hundreds of thousands of lives," says Salim Abdulla, principal investigator of the Tanzanian trial. "It's an amazing feeling to be a part of [this trial]." (Nayar, 2009).

Malaria fact file

Follow link below for full fact file: **http://www.nature.com/news/2008/080227/full/news.2008.622.html**

Rachel Courtland
Malaria continues to be a global problem, but is the end in sight?The areas most at risk are in sub-Saharan Africa, South America, and Southeast Asia.

WorldMalariaFull.jpg
Are there any success stories?
Bed nets and drugs have cut the malaria burden by as much as half in Zanzibar, Ethiopia and Rwanda. But these countries have a low malaria transmission rate, making the disease easier to control. Zambia has a hopeful and ambitious project aiming to cut the incidence of malaria by 75% (Courtland, 2008).
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