Microbiology: Malaria, Essay Example
Malaria is an infectious disease that is caused by a Protozoan parasite (Plasmodium malariae) that is transmitted by a mosquito. (The Malaria Site) Malaria is also a disease that causes the most deaths worldwide and threatens more than one-third of the world’s population. The disease is found in the tropical zones of Asia, Africa, and South and Central America. (NIH, 1) The disease has been document in up to 500 million cases each year, primarily children, and with 1 million of the cases resulting in death. (NIH, 1) There are four species of the Plasmodium parasite that are capably of infecting humans. The parasite enters the individual through an infected Anopheles mosquito. The Anopheles mosquito injects saliva which is carrying the infectious form of the malaria parasite, the sporozoite, directly into the bloodstream. (NIH, 7) The sporozoite further matures and thousands of mature parasites are released into the host (human) bloodstream. (7) Malaria produces different types of systems in the host known as paroxysms. These have stages of chills, fever and sweating, as well as headaches, fatigue, muscle pains, malaise, nausea, and diarrhea. (16) The main part of the host that the parasite infects is the RBCs. In addition, the parasite can affect the RBCs at different stages of cell development , which leads to high levels in the blood and many symptoms. (17)
Malaria is a Protozoan, which are unicellular eukaryotic cells from the Phylum Apicomplexa. The plasmodium in this Phylum is characterized with vesicular nuclei that have one or more nucleoli that contain the DNA or genetic material. In addition, the plasmodium in this Phylum has ciliate that help the organisms with movement. The malaria plasmodium parasite has an intracellular life cycle and the parasite must enter a host cell in order to survive and duplicate. The life cycle of the malaria parasite begins with the transmission of the sporozoites from the vector mosquito. The sporozoites enter the hepatocytes or blood cells through the involvement of surface proteins of the sporozoite and host cell. The cells then develop into preerythrocyic schizonts between 5-15 days. The cells could exhibit a dormant stage, where they remain within the liver of the host for weeks and even up to years. During this, it is possible for the host to continually have relapses of malaria. The preerythrocytic schizont contains 10-30,000 merozoites. The merozoites are released into the blood stream and begin invading the blood cells. The merozite undergo further maturation from ring, trophozoite and schizont stages and in the process ruptures and releases more merozoites into new blood cells. (Perlmann and Troye-Blomberg, 3) If an Anopheles mosquito bites the host, the mosquito takes in the mature parasite cells which form macrogamete’s which undergo sexual reproduction and form zygotes in the midgut of the mosquito. After maturation occurs in the mosquito and under temperature conditions, the sporozoites are released into the salivary glands of the mosquito, where the mosquito can bite a host and allow the malaria cycle to occur. (4)
In order to determine if an individual is infected with malaria, blood smears are examined from finger pricks under a microscope. The blood smears are spread out on a slide and the specimen is stained, using the Giemas stain technique, in order to illustrate the appearance of the parasite. In addition, there are other tests, such as antigen detection kits are used, referred to as Rapid Diagnostic Tests (RDTs) as an alternative to microscope detection. (CDC)
As mentioned previously, the transmission of malaria occurs through the bite from an affected Anopheles mosquito; therefore, it is skin to blood contact with the mosquito that allows entry for the parasite. In addition, there are cases of malaria through contact with contaminated blood, as well as maternal to fetal contamination during pregnancy. Furthermore, since malaria is present in the RBCs, the parasite can be transmitted through blood or organ transfusions or transplants, as well as through the sharing of contaminated needles in drug use. (NIH, 12)
Malaria is a prevalent disease in many countries, and although the disease can be successfully treated, along with a vaccination to prevent the disease, the disease is most common in low economic areas. Therefore educating the public and providing the vaccinations is the problem, as well as the trying to minimize the amount of mosquitoes in that area.
CDC. Malaria Diagnosis. (2012) http://www.cdc.gov/malaria/diagnosis_treatment/diagnosis.html
The Malaria Site. (2011) The Malaria Parasites. Available at: http://www.malariasite.com/malaria/MalarialParasite.htm
NIH. Understanding Malaria. Fighting an Ancient Scourge. U.S. Department of Health and Human Services. National Institutes of Health. National Institutes of Allergy and Infectious Diseases. (Feb. 2007). NIH Publication 07-7139. Pp. 36 www.niaid.nih.gov/topics/malaria/documents/malaria.pdf
Perlmann P, Troye-Blomberg M (eds): Malaria Immunology. Chem Immunol. Basel, Karger, 2002, vol 80, pp 1–26.
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