Plasmodium/Human symbiosis Life Cycle and Importance
What is Plasmodium? Plasmodium is an apicomplexan (previously called sporozoans) that causes malaria in humans. An apicomplexan is a protist that disseminates small infectious cells called sporozoites., and has organelles that are specialized for penetrating host cells and tissues, which are called apical complexes.
The Plasmodium Life Cycle
The Life Cycle of Plasmodium Continued A female anopheles mosquito bites a person that has malaria, and picks up plasmodium gametocytes Gametes form from the male and female gametocytes and fertilization occurs in the digestive tract of the mosquito. An oocyst develops from zygote in wall of mosquito’s gut. Sporozoites develop in the oocyst and migrate to mosquito’s salivary gland. Mosquito bites another person, releasing the plasmodium sporozoites into the bloostream, where they then travel to and enter the victim’s liver cells. This way, the small cells can avoid the lymphocytes (blood cells that identify invasions of foreign bodies) in the blood stream. Several days pass, and the sporozoites undergo multiple divisions to become merozoites. The merozoites then use their apical complexes to penetrate the red blood cell and enter it. The merozoites then grow and divide asexually, and repeatedly break out of the red blood cells in intervals of 48 or 72 hours, which triggers the response of the immune system, and subsequently the symptoms of the immune system response to malaria show; periodic chills and fever. Other merozoites infect new red blood cells. Some merozoites divide sexually to form gametocytes, which can then be picked up by the next anopheles mosquito to bite the infected person, and the cycle starts over again.
Trivia and Current Research A gene has recently been identified that may be the cause of plasmodium resisitance to chloroquine; an important antimalarial drug. This discovery may pave the way for methods of preventing drug resistance in plasmodium. Bill Gates has recently told the BBC that a malaria vaccine is in “phase three” of its development, in other words, it has begun the trial phase. He added that “a fully effective vaccine will take five to ten years.” BBC news: “ Gates says malaria vaccine could ready in three years”
Impact of Malaria Source: ndex.htm Leading Causes of Death in Children Under Five Years of Age, Estimates for (Source: World Health Organization, The World Health Report 2005) RankCause Numbers (thousands per year) % of all deaths 1Neonatal causes3, Acute respiratory infections2, Diarrheal diseases1, Malaria8538 5Measles3954 6HIV/AIDS3213 7Injuries3053 Other causes1,02210 Total10, According to the World Health Report and the CDC, Malaria kills 853,000 children under 5 per year.
Review Questions and Additional Information What is an Apicomplexan? Where do the sporozoites go after being transferred into the blood stream of the victim? What specialized organelle is responsible for penetrating host cells and tissues? What do sporozoites become after multiple divsions in the liver? Where do these cells go, and how? What part of the mosquito do the sporozoites travel to? Where does the fertilization of gametocytes take place? Is plasmodium eukaryotic or prokaryotic? Additional Information on Plasmodium and Apicomplexans Page 527- Description of Apicomplexans Page 528- Life Cycle of Plasmodium and Description
Answers To Review Questions An Apicomplexan is a protist that has specialized organelles made for penetrating host cells and tissues The liver Apical complex Merozoites Into the red blood cells, by penetrating the cell with the apical complex The salivary glands The wall of the mosquito’s digestive tract Prokaryotic
Sources Cited McGraw Hill: hill.com/olc/dl/120090/bio44.swf “The Impact of Malaria, a Leading Cause of Death Worldwide.”The Department of Health and Human Services Center for Disease Control Biology. Campbell, Neil; Reece, Jane; Mitchell, Lawrence Animal Planet TV, “Monsters Inside Me: Living With the Enemy.” 1&feature=fvwp