Thursday, March 26, 2009

The Malaria Parasite Is More Powerful Than You Think

In his New York Times article entitled Manipulative Malaria Parasite Makes You More Attractive (To Mosquitos), Carl Zimmer discusses a recent study which has found that the malaria parasite, plasmodium, is able to manipulate mosquitoes to make them more attracted to humans. The malaria parasite has been on this planet longer than humans and scientists have always been intrigued by its incredible ability to survive. This new discovery gives them a little bit more understanding of how this tiny, single-celled parasite has managed to evade their attempts to eradicate it. Scientists first started making discoveries about the ability of some parasites to manipulate their hosts in the 1970s. They found that this ability to manipulate is common for parasites which require more than one host during their life-cycle. The first discoveries about plasmodium’s abilities to manipulate their hosts were discovered in mosquitoes. When mosquitoes drink the malaria-infected blood of a human, the malaria parasites immediately begin to manipulate their new host by making it more cautious about finding another human or animal to feed on. The parasites manipulate the mosquito in this way to make the mosquitoes survival more likely. The parasites want the mosquito to survive because they need a period of time to develop within this host before they can be transferred into another one for further development. When the parasite is prepared to move on to a new host, it changes its manipulation of the mosquito. The parasite causes their host mosquito to become twice as likely to bite more than one person in a night as well as causing it to spend more time drinking the blood of its victim. The most recent malaria studies show that these parasites are also able to manipulate humans as a mode of survival. After the plasmodium enters the human body, it spends time developing in the liver. The parasite then multiplies and invades blood cells. The parasites feed off these blood cells, continuing to multiply, until the blood cells burst. This process is then repeated. These parasites can then be picked up by mosquitoes, enabling the survival of the species. Scientists have discovered that this survival has been facilitated by the parasite’s manipulations of humans. Research indicates that mosquitoes are more attracted to humans who are infected with malaria than humans who are not. Thus, the spread of the disease is facilitated. Scientists are still unsure of how the parasites make infected humans more attractive to mosquitoes. However, they feel that once this discovery is made, huge advances could be made in the fight against malaria.
Unknown Terms
Gametocytes: a cell capable of dividing to produce gametes (Biology Online)

The more I read about the malaria parasite, the more impressed I become at how advanced it is. It is incredible that something as tiny as a parasite can have the ability to control the behavior of a mosquito. It is no wonder that it has been such an uphill battle to control the spread of malaria. It gives me hope that scientists are making so many discoveries about this parasite that kills over one million people per year. Once researchers discover what plasmodium does to attract mosquitoes to humans, they could formulate a way to interfere with that manipulation and hinder the spread of the disease. However, malaria has proven to be a master of adaptation and even this might not bring about an end to the disease.

"Gametocytes." Biology Online. 3 Oct. 2005. 26 Mar. 2009.

Zimmer, Carl. "Manipulative Malaria Parasite Makes You More Attractive (To Mosquitoes)." New York Times 9 Aug. 2005. 26 Mar. 2009 .

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