In the war against malaria, public health officials have drained swamps, sprayed mosquito-killing insecticides, and doled out medication in an attempt to reduce the disease's toll.
Now, researchers are looking for ways to enlist the buzzing mosquito itself in the fight. They are experimenting to see if the creature's genes can be changed or controlled in ways that destroy the malaria parasites it carries before it can pass them on to people.
Researchers say an important step along this path has been taken by a team of scientists in Europe. They've discovered three mosquito genes that appear to govern how the insect's immune system responds - or fails to respond - to the parasite's presence.
The discovery, reported in today's edition of Science, opens the door to designing chemicals that can prevent these genes from protecting the parasite, they say. This represents "a promising avenue to decrease the prevalence of malaria," says George Christophides, a scientist at the European Molecular Biology Laboratory in Heidelberg, Germany, and a member of the research team.
The results are significant, says Marcelo Jacobs-Lorena, an infectious disease specialist at the Johns Hopkins Bloomberg School of Public Health. "The parasite, when it develops, is a foreign organism" inside the mosquito, he explains. "But there are few clues on how it defends itself against the mosquito's immune system. This is a major step forward in understanding this relationship."
The emphasis on bioengineering to fight malaria has emerged at a time when researchers say the insects and the type of parasite they carry have become increasingly resistant to drugs and insecticides.
Moreover, insecticides that do work often are improperly applied, blunting their effectiveness. Some specialists say if left to themselves, these factors in the next 20 years could double today's annual death toll of 1 million to 3 million people. Young children are said to account for many, if not most, of those fatalities.