MOSQUITOES CAN BE OUR ALLIES IN THE FIGHT AGAINST MALARIA

When mosquitoes feed on the blood of an infected person they become infected with malaria parasites which grow and develop inside the mosquito for a couple of weeks. Malaria occurs in human beings when malaria parasites are ‘injected’ with the mosquito’s saliva into a person’s blood. Therefore, mosquitoes are often viewed as the enemy to humans but this is a common misconception as, according to Dr George Christophides from Imperial's Department of Life Sciences; "Mosquitoes are known as the 'bad guys' that spread malaria, but these insects are unwilling carriers of the disease, whose immune systems try to fight it, just like ours do”. In fact, as soon as the malaria parasites enter the mosquitoes bloodstream, most of them are killed by the mosquitoes immune system. Unfortunately, a couple of these parasites manage to escape undetected through the immune system and go on to divide, multiply and finally infect humans.


Image 1: Human red blood cells bursting after infection of malaria (from scienceblogs.com)



Image 2: Malaria life cycle (from http://www.unituebingen.de/modeling/Mod_Malaria_Cycle_en.html)



The new study, conducted by the Imperial College London team, shows the precise method by which the mosquito's immune system functions, killing 80 - 90 percent of the malaria parasites. The team discovered that these parasites are detected by a pair of proteins, called LRIM1 and APL1C. These proteins belong to the mosquito’s infection surveillance system and activate a third protein in the insect’s blood called TEP1, which seeks out the parasitic invader and binds to its surface. It then destroys the parasite by punching holes in its cell membrane. This knowledge of the detection and killing of the parasites could be used to develop new chemical or genetic techniques to improve the success rate of the mosquito’s detection, so that 100 percent of the parasites can be killed inside the mosquito, hence preventing the transmission of malaria from mosquitoes to people. Dr George Christophides stated that, “now that we know exactly how their [mosquitoes] immune systems attacks malaria parasites, we need to work out how a small number of parasites manage to evade detection by this system. Only a few manage to get past the mosquito's defences, but that's all that's needed for the disease to be transmitted to humans. If we can figure out how some parasites manage to sneak through undetected, hopefully we can find a way to bolster the mosquito's defences to catch them all.”

Now that the means by which malaria parasites are detected and killed by the mosquitoes they infect has been revealed, this discovery could help researches find a means to block out the transmission of malaria from the mosquitoes to humans.

Original article:
http://www.sciencedaily.com/releases/2009/03/090305141641.htm (2009, March 13). How Mosquitoes Could Teach Us A Trick In The Fight Against Malaria. Science Daily. Retrieved March 14, 2009.

By Lin Kanungo (42044796)