Releasing Genetically Engineered Mosquitoes Poses Unknown Risks To Florida

A recent announcement made by a UK-based biotechnology company known as Oxitec has caused quite a stir in some Florida communities as of late. This is because Oxitec plans to release 5,000 to 10,000 genetically modified mosquitoes over an as-of-yet undisclosed 36-acre block in the Florida Keys, most likely Key West near the Key West Cemetery. The experiment is being presented to the public under the guise of an attempt to eradicate mosquito-borne illnesses, specifically Dengue fever.

The mosquitoes have been genetically modified to survive only in the presence of tetracycline, a commonly used form of antibiotic, and the stated goal for these mosquitoes, which are strictly males, is that they will mate with natural females, pass on their tetracycline-dependent traits to the offspring, and then die themselves. The idea is that an entire generation of mosquitoes will die off as a result of this process.

What has environmentalists, GMO opponents, and a large variety of Floridians up in arms, however, are the numerous questions that such an experiment raises.

For instance, as Eric Hoffman of Friends of the Earth asks, “What are the ecological risks of released GE mosquitoes including the risk of disrupting food chains or providing a new ecological niche more dangerous insects to take the place of Aedes Aegypti (the type of mosquito believed to be associated with Dengue Fever)?” The fact is we simply do not know what kind of effects releasing genetically modified mosquitoes into a natural setting will have.

Furthermore, even if the experiment is successful, what would be the result of eradicating an entire population of mosquitoes? Mosquitoes are a food source for many types of fish, birds, and other insects, and removing them from the food chain would leave a potentially large gap for the creatures that rely on them for sustenance. In the end, we do not know what would happen to the delicate food chain if Aedes Aegypti are removed from the ecosystem.

Not only that, but eradicating the Aedes Aegypti type of mosquito might well leave the area open to invasion by other species who may, in fact, be much more dangerous to human health. For instance, the Asian Tiger mosquito, considered one of the most invasive species in the world, is known to be a carrier of both Dengue fever and the West Nile Virus. What would be the result of an Asian Tiger invasion into South Florida? An eradication of Aedes Aegypti might well provide us with an answer.

Another risk associated with the Oxitec experiment is the potential for the release of genetically engineered biting females into the environment. Since female mosquitoes are the mosquitoes which bite humans, Oxitec claims that its GE mosquito population is an all-boys club. However, due to the method by which the mosquitoes are sorted, the potential for release of female mosquitoes is very real.

As Hoffman writes, “The sorting is conducted by hand and could result in up to 0.5 percent of the released insects being female. This would raise new human health concerns as people could be bit by GE mosquitoes. It could also hamper efforts to limit the spread of dengue fever.”

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Additionally, the fact that the mosquitoes are modified to die in the absence of tetracycline is also problematic. This is because tetracycline is a commonly used antibiotic in agricultural production and sewage treatment. Therefore, if there were some contamination of an area with this specific type of antibiotic, or if the existing levels are high enough in the first place, the GE mosquito population could potentially persist and co-exist with the natural mosquito population.

If these mosquitoes were to survive long enough, it would be possible that they could begin to develop and pass on traits that allowed them to live even in the absence of tetracycline, thereby creating the opposite effect of the experiment’s stated purpose. Indeed, who knows what the levels of tetracycline exists in the areas of Florida where the mosquitoes will be released? Have they ever been tested?

And what of it if they have been? Are we really to expect the mosquitoes to stay within the borders designated to them by Oxitec?

In line with this mode of thought is the question of whether or not the Dengue fever itself could begin to evolve and become more virulent and deadly as a result of the GM release. As Hoffman writes,

Concern also exists around the possibility of the dengue virus to evolve and become more virulent in response to the introduction of GE mosquitoes. The fact is that the virulence and spread of disease combined with mosquito population levels and behavior involve incredibly complex systems and [are] difficult to predict in advance. Significantly more research is needed on these and other potentially unintended consequences of the introduction [of] GE mosquitoes.

Researchers do not know much about the correlation between population levels of Aedes Aegypti and dengue fever infection in humans. According to a 2002 article in Science, the density of the Aedes Aegypti populations is at best weakly correlated with human infection rates. This is due to the fact that mosquitoes ‘persist and effectively transmit dengue virus even at very low population densities because they preferentially and frequently bite humans.’ Additionally, any introduction of GE mosquitoes that does not eradicate a population could lead to increased survivability of the dengue virus and increased risk of human infection.

The staggering costs of these eradication methods, and their extremely profitable potential for companies like Oxitec, should also raise questions regarding the Florida mosquito drop.

Because mosquitoes continually reproduce, it would be necessary to continually release GE mosquitoes into any given area where the extermination plans are being carried out. However, even Oxitec itself does not claim that continual release of the GE mosquitoes would lead to a population collapse, as the GE males were only half as successful at mating as the natural mosquitoes according to data that was provided via unpublished results from previous GE mosquito releases in the Cayman Islands. The truth is, no one knows for sure exactly what the results of continual or even one-time release would be.

It is for this reason that mosquito releases would likely occur every few months, or even every few weeks. Oxitec itself has suggested that, in order for any given project to be adequately carried out, at least 100 million mosquitoes must be stockpiled.  

Interestingly enough, it should be noted that the continual release of GE mosquitoes as part of a mosquito-borne illness eradication program would lock any country or community that becomes a client of Oxitec into repeated payments to the corporation due to the fact that Oxitec’s mosquitoes are patented.

From Oxitec’s point of view, the release of GE mosquitoes is a money-making gift that keeps on giving. Especially since the mosquitoes would have to be released over and over in order to keep the population of natural mosquitoes down. If a country, state, or community decides to stop payment to Oxitec, or end the release of the GE mosquitoes, then the natural population of mosquitoes would likely rebound and with it would come the possibility of the increase of the prevalence of disease.

According to Eric Hoffman, Oxitec has never demonstrated or even commented as to the effects of halting the release of the mosquitoes after projects have already begun.

If governments are truly concerned about the prevention of mosquito-borne illnesses, they should take a look (if they are haven’t already) at some of the proven methods of reducing the contraction of these types of diseases.

It has been known for years that community education programs, insecticide-treated bed nets, window curtains, and water jar lids have a significant effect on reducing Aedes Aegypti populations and, hence, the potential for contraction of diseases like Dengue fever.

While the above-listed methods of disease prevention carry their own risks (constant exposure to insecticides, etc.), the risk related to releasing GE mosquitoes into an open and natural environment are much more frightening. This is, largely, because they are unknown, but also because their adverse effects can have drastic effects throughout the local, regional and perhaps even global ecosystem.

That is, unfortunate side effects are unknown for now.

If we don’t make our voices heard quickly, we may found out just what happens when unnatural creatures are turned loose on a natural habitat.