Genetically engineered mosquitoes developed by British biotech firm Oxitec as an approach to controlling dengue fever have been caught up in controversy since 6,000 of them were deliberately released to an uninhabited forest in Malaysia in a trial in December 2010.

The move took many local people and international observers by surprise. For the most part, the problem was not that the mosquitoes were GM or ineffective—previous trials in the Cayman Islands were very successful. Rather the locals took aim at the lackluster efforts made by Oxitec and the Malayan government to consult and notify the public about the trials (see "GM mosquitoes wipe out dengue fever in trial" and "Letting the bugs out of the bag").

Unsurprisingly anti-GM campaigners went for the company’s jugular over the incident, and have been trying to bring them down since. In the latest thrashing, green groups including GeneWatch and Friends of the Earth say Oxitec tried to hide results showing the GM mosquitoes could survive in the wild (Daily Mail).

Oxitec engineered the males so that they will die unless they are given the antibiotic tetracycline which is not generally available once they are released into the wild. The green groups obtained a study showing that 15 percent of the offspring of lab-bred GM mosquitoes survived when fed on cat food which contains low levels of tetracycline. Tetracycline can sometimes be found at low levels in the environment. This represents a "failure of the technology," they say.

The green groups have made "inaccurate public assertions" with the purpose of causing "anxiety" about GM technology and its the regulatory process, counters Oxitec. Given how the Daily Mail covered the story, Oxitec has a point.

The green groups' claims have "no substance as they could have known had they asked us about any part of it," Luke Alphey co-founder and chief scientist of Oxitec told Nature.

In further studies Oxitec investigated whether the tetracycline levels that can be found in the environment are likely to lead to survival of our mosquitoes.

“While tetracycline can be found in the environment in isolated areas it is not present in sufficient quantity to ensure survival of the mosquitoes,” the company says.

About two-fifths of the world’s population are at risk of contracting dengue fever. The green groups "risk undermining the chance of a real solution coming to cultures who have a real problem," the company says.

The fight continues.

This post is reproduced with permission from the magazine Nature. The article was first published on January 12, 2012.