Genetic discovery may eradicate malaria

[DRJJ]

http://www.theage.com.au/news/world...adicate-malaria/2007/03/20/1174153063164.html

March 21, 2007


THE costly effort to eradicate one of the world's deadliest diseases has received a controversial boost ? genetically modified mosquitoes that cannot pass on malaria.

Scientific trials have revealed that the GM mosquitoes could quickly establish themselves in the wild and drive out natural malaria-carrying insects ? and break the route through which humans are infected.

The strategy is likely to be contentious because it would require the unprecedented release of tens of thousands of GM organisms into the wild. But it has raised hopes among scientists, some of whom believe it may be powerful enough to bring under control a disease that strikes 300 million people a year and causes more than a million deaths.

Plans to combat malaria with disease-resistant mosquitoes have been hampered in the past by fears that adding crucial resistance genes weakens the insects, making them too feeble to survive in the wild. For the idea to work, the malaria-resistant insects must breed and become dominant, so that the parasite is not picked up from infected animals and passed on to humans through insects.

Researchers led by Marcelo Jacobs-Lorena, of the Malaria Research Institute at Johns Hopkins University, created genetically modified mosquitoes by giving them a gene that made it impossible for them to pass on the plasmodium parasite that causes malaria. About 1200 GM mosquitoes were released into a cage holding malaria-infected mice and the same number of wild mosquitoes.

The researchers found that the GM mosquitoes slowly became the majority, reaching 70 per cent in nine generations. The scientists believe that even though malaria resistance weakened the mosquitoes, making them immune to the parasite meant they fared better in the long term than insects infected with it because they lived longer and laid more eggs.

"This fitness advantage has important implications for devising malaria control strategies," the researchers wrote in the Proceedings of the National Academy of Sciences.

The finding was hailed as welcome proof that GM mosquitoes, made with cheap laboratory techniques, could ultimately have a greater impact on malaria than chemical sprays and other treatments.

Andrea Crisanti, who leads a team working on GM mosquitoes at Imperial College, London, said the latest work raised hopes by showing the insects would be unlikely to die out if released into the wild.

"This has tremendous potential. You can start with a few mosquitoes and in future generations all of them are resistant to the disease. It should be much cheaper than the controls used now, because you have a strategy where the mosquito spreads the gene which confers resistance. You don't need insecticides any more," Professor Crisanti said.

In wild populations, few females carry the malaria parasite, so disease-resistant strains must become well established to affect the spread of disease. Scientists are focusing on ways to perfect how resistance genes are inherited, ensuring they are passed on in every mosquito egg. Normally, offspring have a 50 per cent chance of inheriting a specific gene from the mother.

Trials in sub-Saharan Africa, where malaria kills a child every 30 seconds, could be conducted within five years, but scientists will first have to prove as far as possible that the resistance genes will not trigger a more aggressive form of malaria or spread to other insects.

GUARDIAN

 

[gsgs]

Re: Genetic discovery may eradicate malaria

can someone give a summary with the estimated probability
that it will work and the cost ?

I mean, everything "may" happen ... but how likely ?
Yeah, and 50% "could" die in a pandemic ... but how likely ?

These headlines are not very useful.

also: flu can be airborne transmitted, can be transmitted by mosquitos.
H5N1 can be H2H ...
But they won't tell us, how often,how likely this is estimated.