Malaria-immune mosquitoes could compete in the wild

Posted by Kate Taylor

Researchers at the Johns Hopkins Malaria Research Institute have for the first time managed to engineer the mosquito immune system to block the transmission of malaria.

"The immune system of the Anopheles mosquito is capable of killing a large proportion — but not all — of the disease-causing parasites that are ingested when the mosquito feeds on an infected human," says associate professor George Dimopoulos.

"We’ve genetically engineered this immune system to create mosquitoes that are better at blocking the transmission of the human malaria parasite Plasmodium falciparum."

Dimopoulos' team used one of the insect’s own genes to strengthen its parasite-fighting capabilities.

They genetically engineered Anopheles mosquitoes to produce higher than normal levels of an immune system protein, Rel2, when they feed on blood. This protein acts against the malaria parasite in the mosquito by launching an immune attack involving a variety of anti-parasitic molecules.

The mosquitoes engineered this way remained fit and healthy - important not for animal welfare reasons, but because the genetically engineered versions need to be able to compete with the natural malaria-transmitting mosquitoes.

The team says the Rel2 genetically modified mosquito strain lived as long, and laid as many eggs, as the non-modified wild type.

"Malaria is one of world’s most serious public health problems. Mosquitoes and the malaria parasite are becoming more resistant to insecticides and drugs, and new control methods are urgently needed," says Dinopolous.

"We’ve taken a giant step towards the development of new mosquito strains that could be released to limit malaria transmission, but further studies are needed to render this approach safe and fail-proof."