Kills disease-causing parasite once it becomes infected

There may soon be a new weapon in the fight against malaria - a genetically-modified mosquito that kills the disease-causing parasite once it becomes infected.

Malaria is a leading cause of death worldwide. The mosquito-borne illness was responsible for 655,000 deaths in 2010, according to the latest World Health Organization figures, most of them, young children in sub-Saharan Africa.

Researchers have genetically engineered mosquitoes to boost their immune system, thereby blocking transmission of the disease to humans.
The altered mosquitoes produce higher than normal levels of the immune system protein, Rel2. That activates a host of anti-parasitic molecules which, in turn, launch an all-out attack on the malaria parasite. The parasite enters the insect's gut after it takes a blood meal from infected humans.

"We're basically attacking the parasite with multiple weapons at the same time as it is infecting the mosquito, and that will much make it more difficult for this parasite to develop resistance," says George Dimopoulos at the Johns Hopkins University Malaria Research Institute in Baltimore, Maryland.

So far, the genetically modified, or GM, mosquitoes are breeding and living as long as normal mosquitoes. Dimopoulos says that's good news because he hopes eventually to breed them with mosquitoes in the wild so off-spring are born with heightened immune systems.

While GM mosquitoes could be a powerful weapon against the dreaded disease Dimopoulos says it will remain only one tool in the fight against the deadly malaria parasite.

"Our approach, based on genetically-modified mosquitoes, will only work in areas where transmission of malaria is carried out by a single mosquito species and not multiple species of mosquitoes because we will not be able to genetically manipulate each one of them individually."

Dimopoulos's team worked with Anopheles gambiae mosquitoes, the principal carrier of the malaria parasite in Africa. They are continuing research to see whether the genetic manipulation works on other species of mosquitos that transmit malaria parasites.