Germ-Infected Mosquitoes Can't Spread Dengue
Release of Bacteria-Carrying Mosquitoes Could Halt Dengue Spread
Residents' Decision: Release Mosquitoes or Risk Dengue
It seems odd that anyone would welcome the release of hundreds of thousands of live, blood-sucking mosquitoes in their neighborhoods. But that's exactly what happened in the Queensland towns of Yorkey's Knob and Gordonvale.
O'Neill's team held numerous town meetings and distributed literature describing the experiment. Residents were enthusiastic, according to study researcher Ary Hoffman, PhD, of the University of Melbourne.
"People are tired of dengue and fearful of it. They are quite eager to see new control measures," Hoffman said at the news conference. "We were overwhelmed by the support of the community."
Beginning in January, at the start of Australia's wet season, the researchers began weekly releases of 10,000 to 22,000 bacteria-infected mosquitoes at nearly 200 sites in each town. They eventually released 303,900 mosquitoes.
The plan worked. Nearly 100% of mosquitoes in Yorkey's Knob and over 80% of mosquitoes in Gordonvale became infected with the dengue-inhibiting bacteria.
"Once releases ended, wolbachia continued to increase, until by the end of the wet season we had almost complete penetration," O'Neill said. "We expect these regions should have a much reduced risk of dengue transmission within them."
That remains to be seen. But if it holds true, the researchers already are making plans for regions with year-round dengue transmission.
"We want to conduct large field trials and are looking for approval in Thailand, Vietnam, Indonesia, and Brazil," O'Neill said.
If it works, mosquito releases won't have to continue indefinitely.
"The really interesting thing about wolbachia is it is potentially a one-off intervention and should be able to maintain itself in the mosquito population," O'Neill said. "We expect it to persist and offer control of dengue after a single intervention."
O'Neill and colleagues report their findings in two papers published in the Aug. 25 issue of the journal Nature.