Australian scientists claim dengue breakthrough

The villain: Aedes mosquito - File photo

Friday January 02, 2009
AFP

Dengue is a virulent threat in Thailand, striking thousands into hospital beds per year, and killing hundreds. Last year alone, the fever killed 17 people in Thailand and affected more than 21,000, according to the health ministry.

In Cambodia, at least 132 people died, and the disease caused three deaths among 3,600 cases in Singapore.

University of Queensland researchers said they have successfully infected the mosquito which spreads the tropical disease with a bacterium which halves its 30-day lifespan, thereby reducing its ability to transmit dengue to humans.

Scientists hope their work will help halt the spread of the painful and debilitating disease which affects millions of people each year.

"The key is that really only very old mosquitos are the only ones that are able to transmit the disease," said researcher Professor Scott O'Neill.

"What we've done is put this naturally occurring bacteria into the mosquitos that actually halves their adult lifespan so they don't live long enough to be able to transmit the virus."

The research published Friday in the journal Science is the result of injecting 10,000 mosquito embryos with a bacterium that occurs naturally in fruit flies but has never been detected in dengue-carrying mosquitoes.

O'Neill said the test was designed to see whether the bacterium reduced the lifespan of the insects without killing them or preventing them from breeding and was able to be passed on to offspring.

He said while the laboratory tests, which involved researchers allowing the bacteria-infected mosquitoes to bite their arms because the species needs human blood to breed, had been successful, it would be several years before the technique would be tested in the wild.

"It's really a preventative strategy for preventing dengue fever outbreaks and what we've done is show that it's possible to be done in a laboratory," he told AFP.

"The next stage is now to move it into a more realistic field setting."

There is no known cure or vaccine for dengue fever, which is transmitted by mosquitos and kills more than 20,000 people each year. Also known as "breakbone fever," symptoms include high temperatures and muscle aches.

The Bill and Melinda Gates Foundation donated 10 million dollars to an international research team led by the University of Queensland into a means of defeating dengue fever in 2005.