Scientists move to quell GM mosquito concerns

A genetically modified adult mosquito emerges from its pupa. – PHOTO: OXITEC

Cayman’s Mosquito Research and Control Unit and U.K. biotech company Oxitec tackled questions Tuesday night from West Bay residents concerned about the planned release of millions of genetically modified mosquitoes in their neighborhood.

At the first public meeting about the mosquito release, held at Sir John A. Cumber Primary School hall, residents questioned the scientists on the safety of the project and the apparent lack of public consultation leading up to the release, which is to begin next month.

Oxitec’s Derric Nimmo addresses the public meeting in West Bay on Tuesday night. – PHOTO: KELSEY JUKAM
Oxitec’s Derric Nimmo addresses the public meeting in West Bay on Tuesday night. – PHOTO: KELSEY JUKAM

The MRCU is planning a multi-phase rollout of Oxitec’s mosquito control solution, which involves releasing what they described as “friendly” Aedes aegypti male mosquitoes to help fight the mosquito that transmits diseases such as dengue, chikungunya and Zika. The rollout will begin in West Bay.

About 20 people attended the meeting.

“I am very disappointed that we are coming to a meeting of a foregone conclusion, that the public was not consulted in any way, shape or form, or certainly given any feedback about how we feel being inundated with … genetically modified mosquitoes,” Dwene Ebanks said at the meeting.

He and others at the meeting asked Oxitec representatives why Cayman was chosen for such a project.

Oxitec product development manager Derric Nimmo said the MRCU is “world-renowned” for assessing new technologies for mosquito control and that it is “very interested” in new methods because the current technology for dealing with Aedes aegypti mosquitoes is not working.

“This is a public health menace. It is also a real challenge for people to control,” MRCU Director Bill Petrie said.

Mr. Petrie explained that over the years the MRCU has looked at several methods to suppress the Aedes aegypti mosquito population, and he believes Oxitec’s solution will effectively suppress the species in Cayman.

Zika is spread by the Aedes aegypti mosquito.
Zika is spread by the Aedes aegypti mosquito.

“The essence of this technique is the use of effectively sterile male mosquitoes, which are released in the environment [and] then mate with the wild female Aedes aegypti mosquitoes, which are already out there. The progeny of those female mosquitoes then do not complete development, they all die, so they do not reach maturity,” Mr. Petrie explained. “If you do this over time, we have shown that you can significantly reduce the population of Aedes aegypti in the wild.”

Mr. Nimmo said that because Aedes aegypti mosquitoes live in and around homes and can breed in very small amounts of water, the species is very difficult to control by conventional means. The species has also become resistant to many types of insecticides.

“This technology reaches where other tools cannot,” he said.

Mr. Ebanks also expressed concerns about the technology, and asked Mr. Nimmo whether residents should be concerned about ingesting the mosquitoes, and whether they would have to wear masks when walking outside.

Mr. Nimmo said residents should not be concerned about the possibility of accidentally ingesting a genetically modified mosquito, as it is no more harmful than accidentally ingesting a normal mosquito.

Those at the meeting also expressed concerns about the possibility of female mosquitoes being accidentally released along with the male mosquitoes.

“We do release a small percentage of females … [among] one out of every 10,000 males is a female, so there is a chance that you could get bitten by one of these females,” Mr. Nimmo said. “There is no difference getting bitten by a GM female mosquito than the wild mosquito.”

The U.S. Food and Drug Administration’s Center for Veterinary Medicine came to the same conclusion in its preliminary “Finding of no Significant Impact” in March.

“Based on the data and information presented, FDA concluded that the immunological response in humans and animals to OX513A female mosquito bites is not expected to be different from the immunological response to bites by wild type Ae. aegypti mosquitoes,” the agency said in the statement.

The FDA report was in response to a proposed plan to release Oxitec Aedes aegypti mosquitoes for an investigational trial in the Florida Keys.

Similar releases by Oxitec have been carried out in Panama, three locations in Brazil, and in Cayman’s East End in 2009.

Mr. Nimmo noted that while the GM female mosquito, like its wild counterpart, can carry diseases, “lab” females do not live as long as wild female mosquitoes.

Beginning in June, the genetically modified mosquitoes will be deployed initially to treat an area of about 300 acres, with 1,800 residents, in West Bay. Mosquitoes will be released three times a week, with between 100,000 to 200,000 mosquitoes per release. About 1,000 mosquitoes will be released every 50 to 100 meters along a road.

Mr. Nimmo said those numbers may “sound like a lot,” but after 30 seconds, those 1,000 mosquitoes quickly disappear from sight as they disperse to nearby yards and gardens.

Several mosquito traps will also be set so that weekly monitoring of the rollout can be done.

Mr. Nimmo added that the current mosquito control efforts by the MRCU will continue as normal while the GM mosquito release project is under way.

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  1. …… FDA CONCLUDED that the immunological response in humans and animals to OX513A female mosquito bites is not EXPECTED to be different from the immunological response to bites by wild type..
    That remains to be seen.
    When a conclusion is based on expectation, just EXPECTATION and nothing else, that is scary. Our daily exposure to thousands of synthetic chemicals make us the unwitting guinea pigs.
    Immunological response doesn’t happen overnight. Few years down the road when one is diagnosed with an autoimmune disease it will practically be impossible to connect it to GM mosquitoes.

  2. L. Bell, do you have any scientific evidence for your conclusions and expectations? Because I’m certain the FDA does. Science is based on evidence and probabilities. Nothing is ever 100% certain, but we can make educated conclusions based on experiments and data. But of course fear-mongering based on zero evidence is easy and people love easy. The only thing I can say for certain about this is that mosquitoes are the deadliest animal on the planet and transmit diseases everywhere they appear, most of which have definite, not just possible, negative health consequences.

    • What is science? It is an intellectual left-brain process dependent upon the five physical senses.
      Limits of science in a nutshell. It explains nothing;it can only describe. It proves nothing; it can only verify or disprove. Science cannot deal directly with subjective experience; it can only deal with the objective. “Scientific” does not necessarily mean right,valid or best; it only means that a certain method was followed.
      Belief in science is an act of faith and is, in itself, choice made subjectively and personally, not scientifically. Science is limited by time; tomorrow’s research can not help us today and yesterday’s events can not be directly observed. Science is limited by human bias in the choices of topics upon which the method is applied.

      • God if all you’re going to do is copy and paste woo from some essential oil or anti-vax quacks then there is no use having a rational discussion.

        The only real question I have is were you one of 20 that attended the meeting?

          • Mr or Ms Bell. You have a rather odd take on the value of science and it’s contribution to finding solutions to the world’s many problems. Without science, everything else is just anecdotal.

  3. I am not sure if this is relevant but a couple of years ago my wife and I were in South Georgia Island near Antarctica.

    We were told there had been a massive rat extermination program there as millions of rats had overrun the island.
    I won’t go into the details but there was one very interesting point. They said it was essential to kill every single rat. If just one breeding pair was left within a few years the island would be overrun again.

    This mosquito program won’t be 100% effective. How long will it take for the population to recover? Or will they?

    • This is actually relevant. Oxitec’s program will not completely eliminate the population and it will recover if they stop releasing the mosquitoes, however from what I’ve read this is pretty well known. I think the point of releases like this isn’t to completely eliminate the population, but to be another tool in fighting the population and to further learn the best ways to combat the problem.

  4. My concerns about this project is that no one know a 100% what effects that the GM mosquitoes would have on the human . I wonder how much money is this program going to cost the government ? Why would the first release be done in West bay ? Do West bay have more mosquitoes than any other part of the Islands ?
    This program sounds like a other everlasting program .

    • No one knows 100% about anything we encounter in life. Refer to my comment above though. Mosquitoes are the most deadly and disease causing animal on the planet, we do know that with almost absolute certainty. And yes there is a cost-benefit equation to be evaluated for this program, which I’m assuming elected officials have done. Just FYI though, this was first done in east end a few years back as a test. I’m assuming they are doing it in West Bay now as it is more populated and they can evaluate the results a little better. That would be a good question to have asked if you attended the public meeting.

  5. The more I read this article , the more I get confused to how this project is going to work .
    These GM mosquitoes would be released in a certain area , how would these mosquitoes know to stay in that area? And MRCU would also continue it’s operation , Then how would we know what is killing of the bad mosquitoes ? The numbers on the released GM mosquitoes don’t ad up too.

  6. Mother nature is a unpredictable mistress in the event that the offspring reaches maturity. How do we monitor that? Adaptation happens overtime what happens if we are over-run by a new sub species of the already problematic Aedes aegypti in the wild?

    On the other hand if this project works so well, are we knocking off a species from the food chain what other organisms benefit from the larva or even the Aedes aegypti itself as a food source?

    These are questions that can’t be answered without trial and error. All I want to know is what safe guards are in place if this little petri dish experience goes bad. The scientist can go back home but we have to live with this experiment.