3 Jan 2009

Scientists make dengue fever breakthrough

7:23 am on 3 January 2009

Australian researchers have made a breakthrough that could help curb the spread of dengue fever, a tropical disease which kills thousands of people every year.

Scientists from The University of Queensland say they have proven they can limit the lifespan of the type of mosquito - Aedes aegypti - which spreads the disease.

There is no vaccine or cure for dengue, a painful and debilitating disease also known as breakbone fever. It harms up to 100 million people and kills more than 20,000 every year.

The virus is passed to humans when mosquitoes carrying it feed on their blood, and while there have been efforts to eradicate them using insecticides, these have been fraught with problems, including the ability of the mosquito to become resistant to the chemicals used.

But in a paper published in the international journal Science, researchers say they can halve the insects' lifespan by infecting them with a bacterium that is harmless to humans and other animals.

The breakthrough could dramatically curtail the insects' potential to spread the disease because only older mosquitoes can transmit it to humans.

PhD student Conor McMeniman carried out the painstaking research. He used super-fine needles to manually inject 10,000 mosquito embryos with the bacterium, then encouraged the surviving mosquitoes to feed on his own blood.

"We ended up having to inject thousands of embryos to achieve success, but it was well and truly worth it in the end," he said.

Professor Scott O'Neill, head of the university's School of Biological Sciences, said researchers would now conduct field experiments in northern Queensland.

"If that proves successful we hope to deploy this new dengue control measure in other parts of Australia, as well as Thailand and Vietnam."