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Genetically Modified Mosquitoes Will Guard the World Cup Against Dengue

The future of public health is here at last, and it’s just in time for the world's biggest sporting event.
Photo by John Tann

The future of public health is here, and it’s just in time for the World Cup. Scientists have developed a way to combat the spread of dengue fever by genetically modifying the mosquito through which it is spread. This is the first time that genetically modified (GM) insects are being released on this scale into the public to combat disease. Brazil, which approved a massive trial of these GM mosquitoes, may decide to permit commercial releases.


Dengue fever is prevalent in equatorial and tropical countries, which provide a perfect breeding ground for mosquitoes. Currently Brazil is experiencing an epidemic of dengue fever, with approximately 1.4 million confirmed cases last year, and officials are warning that the mosquito population and the prevalence of the virus will peak during this summer’s World Cup — in three of the major host cities: Fortaleza, Natal, and Salvador.

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Dengue is carried by the Aedes aegypti species and spreads to humans through the bite of an infected mosquito. It causes fever, rashes, bleeding, and shock. It also causes severe joint and skeletal pain that makes victims feel like their bones are breaking, which explains Dengue’s other common name as “breakbone fever.”

The disease is endemic in more than 100 countries and about 40 percent of the world’s population live in a region with dengue. Rates of dengue have been steadily increasing in recent years due to rising temperatures, which mosquitoes like, and greater mobility of people and goods, which disperses them widely and rapidly.

There is no vaccine for dengue and it is primarily treated with home remedies and medication to treat the symptoms of the disease. Fumigation and larvacides help to reduce the population of the carrier mosquito, but Aedes aegypti has developed a resistance to many of the chemicals used. So more weapons — and mightier ones than mosquito nets and bug swatters — are needed.


And the British biotech company, Oxitec, may be coming to the rescue. It has developed a new method of fighting dengue by injecting a lethal gene into male Aedes aegypti mosquitoes as a way to kill off the species.

“This technology allows us to cause death in the offspring in the next generation,” explains a video on Oxitec’s website. “Effectively it’s birth control for insects.”

Oxitec has teamed up with the Brazilian biotech company Moscamed to raise and release these new GM mosquitoes in eastern Brazil, in the farm town of Jacobina. The GM mosquitoes are expected to mate with the local mosquito population, and the results will be monitored during a two-year testing period.

Although Oxitec and Moscamed ensure that this technology is safe and will not lead to a mosquito version of Jurassic Park, not everyone is convinced of the safety of messing with nature.

GeneWatch UK, a British organization, has cautioned against implementing this technology without conducting further tests to ensure its safety for both humans and the environment.

“There are no published toxicity tests to show that swallowing GM mosquitoes or being bitten by surviving GM females is safe for humans, pets, and wildlife,” said GeneWatch in a statement released yesterday.

“In the case it is approved for commercial use, the decision will have been based much more on propaganda than on concrete data from field studies," said Gabriel Fernandes, an adviser with the Brazilian environmental organization AS-PTA, in the statement.

Oxitec reported that the mosquito population in the Cayman Islands decreased by more than 80 percent after the release of 3.3 million GM mosquitoes in 2009 on several controlled test sites. Although this experiment was lauded as a success by Oxitec, it was criticized by other international and environmental organizations because it was conducted without consent or knowledge of the local population and little independent oversight

Despite concerns over the safety of this new method, GM bugs are likely coming to the US. The primary method of fighting mosquitoes and the spread of dengue in the US remains the application of chemical repellents, but the Food and Drug Administration is also considering the use of GM mosquitoes. Another dengue outbreak like the one Florida experienced in 2009 — and scientists warn that more outbreaks are likely in the future — could bring pressure on the FDA to mobilize these GM troops.

Photo via Flickr