Flightless mosquitoes may curb dengue

Genetically altered mosquitoes that cannot fly may help slow the spread of dengue fever and could be a harmless alternative to chemical insecticides, according to scientists.

The team from the US and United Kingdom genetically altered mosquitoes to produce flightless females. They say spreading these defective mosquitoes could suppress native, disease-spreading mosquitoes within six to nine months.

There is no vaccine or treatment for dengue fever, which is endemic in the tropics and is particularly prevalent in Asia and the western Pacific. The disease, which causes severe flu-like symptoms and can kill, is spread through the bite of infected female Aedes aegypti mosquitoes.

"This could be the first in a new wave of products that might supplant insecticides," says researcher Anthony James of the University of California, Irvine.

There are an estimated 50 million cases of dengue fever each year and about 2.5 billion people - two-fifths of the world's population - are at risk, mostly in Africa and southeast Asia, according to the World Health Organization.