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.

4 Comments

1. 1. rushil2u 02:34 AM 1/13/12

   I see you haven't mentioned the names of the green groups hounding Oxitec. Perhaps you should. I would love to know more about these people who would happily sacrifice the lives of those they're probably never going to meet.
   
   Here in India thanks to a combination of public ignorance and lack of government interest, diseases like dengue, malaria and chikungunya spread like wildfire every monsoon.

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2. 2. Helen Wallace 04:57 AM 1/13/12

   A few comments:
   1. The article cited claiming that releases of GM mosquitoes "wiped out" dengue in Cayman is incorrect because dengue is not endemic in Cayman and there were no reported cases at the time of the trial.
   2. The results claiming that this trial was successful at repressing the mosquito population have not yet been published.
   3. The releases in Cayman were controversial because there is no biosafety law to regulate the release of GMOs in Cayman and local people were told the mosquitoes were "sterile" not that they were GM.
   4. The concerns are based on documents which readers can access via the original press release on: http://www.genewatch.org/article.shtml?als[cid]=569457&als[itemid]=569476 . The evidence of the 15 percent survival rate when the moquitoes were fed cat food was blacked out in the version released to the UK parliament and in response to Freedom of Information requests.

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3. 3. rjvg50 12:10 PM 1/13/12

   This does not explain the mechanism for using the tetracycline just that it 'requires' the anti-biotic. What if the by products of tetracycline and not the entire compound is used by the mosquito? The Jurassic Park Hypothesis is that somewhere and at some time, a variation MIGHT lead to another path to the solution. Once no organism metabolized Nylon since prior to the development of Nylon and its byproducts no organism could exploit this variation. Once a path was found - we have organisms that metabolize Nylon. Just saying.

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4. 4. bucketofsquid 02:34 PM 1/25/12

   The only "threat" this mosquito poses is to the profit margin of Oxitec if they can survive in the wild. As they displace the fertile male mosquitos, if this trait continues into the next generation, no future releases are needed.
   
   My only concern is what happens to natural mosquito predators when their food supply goes away. The bats and such will starve won't they?

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