PARIS - Scientists say they've found on a new way of controlling dengue fever by weakening populations of mosquitoes carrying the virus which causes the deadly disease.
"The results show we can completely transform local (mosquito) populations in a few months," said Michael Turelli, a biologist at the University of California at Davis. "It's natural selection on steroids."
Dengue which affects between 50 and 100 million people in the tropics and subtropics each year, is caused by four strains of virus that are spread by the mosquito Aedes aegypti.
There is no vaccine, which is why scientists are focussing so intensely on mosquito control.
In 2009, Turelli and others hit on the idea of inserting a naturally-occurring bacterial parasite called Wolbachia to shorten the mosquito's lifespan so that the virus would not have enough time to develop.
After initial setbacks, the team of scientists found a non-virulent strain of Wolbachia in the fruitfly Drosphila.
Introduced into the mosquito, the germ prevented the insect from becoming infected by the dengue virus.
At the same time, the Wolbachia which is a symbiotic bacterium, it was also harmless to the mosquito as it exists by living in harmony with its host.
As it lives inside cells and is maternally inherited, this raises the possibility that after a few generations, the introduced dengue-free mosquitoes eventually outnumber dengue-carrying counterparts.
After long consultations with the government and regulators, the scientists released Wolbachia-infected mosquitoes in two locations in Queensland, Australia, this year.
Early results suggest that the introduced mosquitoes have thrived, and "herald the beginning of a new era in the control of mosquito-borne diseases," said Jason Rasgon, a specialist at the Johns Hopkins Malaria Research Institute, Maryland, in a commentary also carried by Nature.
"The advantage of population-replacement approaches is that, once established, they are self-propagating. And because the mosquito population is simply changed rather than eliminated, effects on the ecosystem should be minimal."
The paper appears in Nature, the weekly British science journal.
- AFP/sf
Taken from ChannelNewsAsia.com; source article is below:
Dengue fever under attack through smart mosquito control
