KUALA Lumpur, Malaysia - Environmentalists are still not convinced that the release of between 4,000 and 6,000 genetically modified (GM) male mosquitoes into forests in Alor Gajah in Malacca and Bentong in Pahang will not have an adverse effect on the ecosystem.

Malaysia Nature Society (MNS) president Assoc Prof Dr Maketab Mohamed said it was not satisfactorily assured despite the Biosafety Department saying that the risks are minimal.

Biosafety Department director-general Letchumanan Ramanatha was reported as saying that the experiment was not aimed at finding out how many mosquito larvae died as a result of the release of GM mosquitoes but in determining how far GM mosquitoes, which can live for three days, can fly and how long they can survive outside of laboratories.

Research shows that mosquitoes can generally fly about 200m.

Letchumanan had advised the public not to be alarmed by the projects as only a small number of mosquitoes will be released, and that experiments found the risks to be minimal given the fact that the GM mosquitoes will be greatly outnumbered by the millions of mosquitoes in the forests at the two locations.

It is hoped that the GM mosquitoes would mate with their female counterparts in the wild, causing the early death of their larvae and eventually reducing the Aedes aegypti population.

"Like any Malaysian, we are worried about the high number of cases of dengue and dengue-related deaths in the country, but there are too many unknowns yet to be uncovered (by the Biosafety Department's experiments)," Dr Maketab said.

He urged the government to have a moratorium on the release of all genetically modified organisms (GMO) because of the many unknowns involved.

Centre For Environment, Technology And Development Malaysia chairman Gurmit Singh said the assurance given by the Biosafety Department failed to address concerns such as how it plans to control the GM mosquitoes once they are released in the wild.

"How does the department also prevent the mosquitoes from spreading? This is the first time I'm hearing that they can only travel 200m," he said, adding that it was surprising that the people in Alor Gajah and Bentong were not consulted before the announcement was made.

Gurmit said the department should share its data on similar experiments conducted elsewhere.

"The department also said it had conducted experiments but if they were done under controlled conditions that are far removed from the actual conditions (where the GM mosquitoes will be released), then those experiments are useless.

"We're not convinced that this is the way to go and we're concerned that this experiment will go wrong."

The GM mosquitoes were developed by a British-based insect biotech company, Oxitec.

A total of 38,330 people have been infected with dengue between January and Oct 9, with 117 deaths. There were 32,560 cases and 72 deaths over the same period last year.

As of this month, there were 228 dengue outbreak localities nationwide, with 35 identified as hotspots.