Malaysian Prime Minister Najib Razak said last year the project was an "innovative" way to fight dengue after a lack of success in campaigns urging Malaysians to keep neighborhoods free of stagnant water where mosquitoes can breed.
The number of dengue-linked deaths in Malaysia increased 52 percent last year from 88 in 2009. The total dengue infections rose 11 percent from 2009 to more than 46,000 cases last year.
Scientists argue that such experiments present unknowable risks to the ecosystem as the effects of completely eradicating a species or introducing a mutant variety are difficult to predict. The Malaysian government assured the public that the experiment was a success, that "all the mosquitoes were killed with insecticide", and that no further experiments will be initiated until results of this one are analysed.