Genetically Modified Mosquitoes – what you should know

The CBC reports Florida will be use genetically modified mosquitoes to combat a recent Zika outbreak in the Florida Keys.

In hopes of stemming the threat of the Zika virus, the World Health Organization approved limited use of genetically modified mosquitoes in Brazil back in March.


This isn’t terribly new. Brazil opened its first genetically modified mosquito farm back in 2012 in the hopes of controlling the spread of dengue fever (http://www.healthmap.org/site/diseasedaily/article/brazil-rolls-out-gm-mosquito-farms-71812#sthash.H8sqkpGv.dpuf).

The mosquitos used for this project were developed by Oxitec, the world leaders in producing genetically modified mosquitoes.

From the Oxitec website:

Oxitec uses advanced genetics to insert a self-limiting gene into its mosquitoes. The gene is passed on to the insect’s offspring, so when male Oxitec engineered mosquitoes are released into the wild and mate with wild females, their offspring inherit the self-limiting trait. The resulting offspring will die before reaching adulthood, and the local mosquito population will decline. – oxitec.com

I know what you might be thinking:

Mosquitos will be wiped out! The delicate balance of the ecosystem will be destroyed!

First, the only mosquito species affected by this is the Aedes aegypti. Oxitec’s genetically modified male mosquitoes are capable of reducing Aedes aegypti populations by as much as 80%.

Aedes aegypti doesn’t just carry Zika virus – it’s also a vector for dengue, yellow fever and chikungunya.

aedes aegypti genetically modified mosquito

Drawing of Aedes Aegypti Mosquito by Emil August Goeldi, 1905- image via Wikimedia

The advantages

Currently, pesticides and mosquito netting are pretty much the only weapons we have against mosquitoes. But they are ineffective. Pesticides also wreak havoc on the environment and can produce pesticide resistant strains of mosquitos. There are already mosquitos that are unaffected by most pesticides, causing sort of “race to the bottom” where companies are forced to produce ever more toxic pesticides.

Pesticides can also kill beneficial insects, including butterflies and bees. And while the EPA has approved some pesticides, it’s hard to know what the long-term safety of these prod

The beauty of genetically engineered mosquitos is that if they become ineffective, they can be re-engineered. And since male Aedes Aegypti won’t be copulating with butterflies, the pollinators are safe (http://www.wsj.com/articles/SB10001424127887324216004578481230316259360).

The risks of genetically modified mosquitoes

There are some potential risks.

The technology is not 100 percent effective, which means that some biting female mosquitos are able to reach adulthood and breed.

Some people fear that the genetic mutations in the male mosquitos will pass to the (biting) female mosquitoes. This might mean the introduction of unnatural proteins into those bitten by these female mosquitoes, which in turn could cause allergic reactions. No reactions have been observed in test populations exposed to the modified mosquitoes.

One genetic modification causes the pupae of the modified mosquitoes to carry a genetic marker called DSred, making them fluorescent. The other causes the offspring to die before adulthood.

Bottom line

Mosquitos kill over 1 million people per year (http://www.hardydiagnostics.com/articles/The-Most-Deadly-Animals.pdf), making them the most dangerous animal on earth. They are also responsible for transmitting deadly parasites like heart worms to dogs and cats.

Genetically modified mosquitoes will cause the death of millions of mosquitoes, but save millions more humans and other animals (including many millions of insects who would be wiped out by pesticides).

There is risk in releasing GMO mosquitoes. But it is false to assume the alternative is risk-free. We don’t know how much death and destruction will be caused by the Zika virus. We don’t know how the virus may mutate. This risk is as “infinite” as the risks of non-intervention.

What we know for certain is that Aedes Aegypti has killed millions and will kill millions more without intervention.

What do you think? Join the conversation!

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