In 2005 the Bill and Melinda Gates Foundation gave the money to an international team led by University of Queensland researchers working on a biological weapon to defeat dengue fever, which kills more than 20,000 people around the world each year and infects 100 million others. About 60 cases have been reported in Cairns in the past two months.

In a paper published today in the journal Science, the researchers report that they have achieved a breakthrough.

Ten years ago, Scott O'Neill, head of the university's school of biological sciences, began working on an idea to use bacteria to kill the dengue fever mosquito, Aedes aegypti, before it was old enough to pass on the disease.

"Only old females are able to transmit the virus to humans," he said. If a way could be found to make them die before they were 12 days old, the virus could be stopped in its tracks.