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Stopping dengue fever with genetically modified mosquitoes

Four hundred years ago, the world was so afraid of Galileo’s scientific ideas that the Catholic Church put him under house arrest for the rest of his life. And he was just describing heliocentrism, the astronomical model where the earth revolves around the sun. Very important to our understanding of the universe, but it was not a life or death matter. 

You would assume that if a new scientific idea that would help people live longer and healthier, then there would be no fear. However, that assumption is disproven again and again with the antivaccine gang and the Big Pharma ad hominems that we hear frequently.

As I’ve discussed on a number of occasions, genetically modified organisms, whether they be crops or animals or other organisms, seem to cause an irrational and unscientific concern. GMOs are generally safe, and we have lots of scientific evidence to back that up. But still, people get scared.

Bring me the Frankensquito

Over the past couple of years, I’ve written about an innovative an small UK based biotech firm, Oxitec, which has developed genetically modified mosquitos (always males), sometimes referred to as  Frankensquitos (at term I fully embrace as being both ironic and descriptive) that would mate with wild females. Those females would produce offspring that would not survive to adults, because the male mosquitoes pass on a gene so that the next generation of mosquitoes would require an antibiotic, tetracycline, in their diet to survive.

And tetracycline is something that isn’t usually available in the the wild. Over time, with multiple releases of males, the population of the Aedes aegypti mosquito, which is the vector for transmitting Dengue fever to humans. would fall to such a level that transmission of the the disease would be significantly reduced, if not completely stopped.

Over time, with multiple releases of males, the population of the Aedes aegypti mosquito, which is the vector for transmitting Dengue fever and other tropical diseases, such as Chikungunya, would fall to such a level that transmission of these diseases would be significantly reduced, if not completely eliminated.

Lifecycle of genetically modified mosquitos.
Lifecycle of genetically modified mosquitos.


Why use genetically modified mosquitoes


The benefits of this type of control of the mosquito are tremendous:

  1. Most important, these genetically modified mosquitoes allow mosquito control districts to avoid or reduce the use of insecticides which have infinitely more downsides to the environment than any imagined beliefs about genetically modified mosquitoes. Insecticides also have effects on other species of insects that are not a danger to humans, or on other organisms including birds and mammals which consume the insects. To significantly reduce a pest like a targeted single species of mosquito without insecticides should be considered a huge environmental benefit.
  2. Unsurprisingly, resistance has developed to four of the six pesticides used against the Ae. aegypti⁠ mosquito in the Keys. There is no danger of this happening with the GMO mosquitos.
  3. Because the modified mosquito only lasts one generation, the net effect to the environment is only one generation, essentially 2-4 weeks, much shorter than any pesticide. So there isn’t a persistent population of genetically modified mosquitoes, all of the ones that descend from the modified males would perish before making a next generation.
  4. It is more efficient and effective than the dominant method for reducing insect populations–the “sterile insect technique” (SIT), which relies upon radiation to sterilize males, which are then released into infested areas to mate. Unfortunately this approach, which has been used since the middle of the last century, has not been effective with mosquitoes, as a result of the fragility of radiated males.

What is this Dengue fever?


Dengue fever is one of four viruses transmitted by the Aedes aegypti mosquito to humans. It infects over 100 million people a year worldwide.

The principal symptoms of dengue fever are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). Generally, younger children and those with their first dengue infection have a milder illness than older children and adults. Dengue hemmorhagic fever (DHF) is a more severe form of dengue infection. It can be fatal if unrecognized and not properly treated in a timely manner. DHF is caused by infection with the same viruses that cause dengue fever. With good medical management, mortality due to DHF is still significant, but can be reduced to less than 1%.

Dengue fever is not transmitted from one person to another with direct contact, only from the bite of the mosquito.

Although Dengue fever is rare in the USA, there have been outbreaks in 2009 and 2010 in the Florida Keys, and one in 2005 in Texas. And with higher temperatures and sea level rises, the mosquito vectors for Dengue will move further and further north putting more of the world population at risk.

Yes, Dengue fever is rare in the USA, but does anyone but your science denying Southern Republican think that mosquitos will respect national borders with human-caused climate change? No.


Oxitec and genetically modified mosquitoes


In an article about the technology, Oxitec seems truly devoted to finding solutions to problems that affect humans:

The company, Oxford Insect Technologies in its unabbreviated form, believes its technique is effective, cheap and far less damaging to the environment than the use of pesticides but its problem is the phrase “genetically modified” and the kneejerk fears it engenders. Critics see a ruthless corporate giant aiming to monopolise a market for commercial ends, which could have unknown effects on unknown things. For many critics, the mystery is often as potent as the evidence. Oxitec could not be more different from the multinationals. It employs 40 people, 35 of whom are scientists. It doesn’t have a public relations department, or even person, instead relying on Hadyn Parry and senior scientists to explain its work to the public.

A small company, made up of mostly scientists dedicated to helping people, is probably the most harmless group of people in the world. They probably sit around a table thinking of every possible issue, thinking through the science as good scientists do.

They seek out evidence, test the null hypothesis, before they test in the wild. Again, the anti-science attitude is that science is something this side of magic, two or three experiments in a test tube, then throw it in a human. That’s not how it works. Oxitec has been doing this for at least 10 years before trying to it in the wild. This isn’t a random idea in a random idea.



When are the mosquitoes going to be released in the wild?


This is not clear as of right now, but the United States Food and Drug Administration is considering a test release of the a few million of these mosquitoes in a limited area of the Florida Keys. Of course, the FDA won’t give the go ahead to the test until they’re satisfied with the safety of the project.

There has been substantial scientific research behind the Oxitec mosquitoes as it proceeded from the laboratory to confined trials to limited field trials. In each case, Oxitec formally notified the governing authorities of their actions, and received approval to do so. Oxitec has conducted field trials in the Cayman Islands, Malaysia, Panama and Brazil, it is preparing to conduct trials in other countries, including the United States. Oxitec’s trials are always appropriately controlled and monitored, by its own and independent scientists, to ensure that they are safe and effective, and are frankly closely monitored by various regulatory bodies.

And the real science, published in one of the top scientific journals in the world, Nature Biotechnology, confirms that it works:

We report data from the first open-field trial involving a strain of engineered mosquito. We demonstrated that genetically modified male mosquitoes, released across 10 hectares for a 4-week period, mated successfully with wild females and fertilized their eggs. These findings suggest the feasibility of this technology to control dengue by suppressing field populations of A. aegypti.

I don’t ascribe to “faith” or “belief”, but I know the FDA will do a good job in being overly careful about this test. But in the end, unless something goes horribly wrong, this will probably go forward

What are the opponents saying?


But of course, after several years of testing, the crazy internet still is opposed to the release of these so-called Frankensquitoes (a name I’ve fully embraced). There are still complaints raining in on the FDA from “concerned citizens” that has probably delayed a decision on release.

Some of the more ridiculous claims of the anti-GMO crowd include:

  • What about the native species of Florida Keys Bats. Are there any studies being conducted to see if these mosquitoes will harm the native bat population? The bats are not particular about the species of mosquito they eat. If A. aegypti is eliminated by this method, it’ll be replaced by other, less dangerous species, which will be just as tasty to those bats. And the genetically modified mosquitoes will also be tasty. It’s not going to be a problem.
  • Speaking about Florida Keys Bats, lets get more, they’ll eat all the mosquitos. No they won’t. It’s some sort of fantasy to believe that you could fill the environment with a predator, and eliminate all the prey. If they did that, they’d all die. And besides, bats in the numbers necessary to remove every mosquito has its own health and environmental issues.
  • That mosquito DNA is going to get injected into humans with unknown consequences. It’s nearly impossible to take this type of claim seriously. If this were possible, we’d have become mosquitoes millions of years ago. A foreign DNA particle injected into the bloodstream by a mosquito would not be immediate incorporated into the human genome, spread through ever cell, immediately killing us. No, the immune system would identify the particle as foreign and eliminate it.
  • The bioengineered genes would pass to the bats. Precisely how is this claim biologically plausible? Exactly how are these mosquitoes, which have a change in one gene so that they require tetracycline to survive, going to harm a bat. Because, as I’ve stated before, the DNA/RNA of food sources do not get transferred to the consuming species. It’s physiologically impossible, and betrays a high degree of biological ignorance for anyone who writes that.  O
  • Will the more virulent Asian tiger mosquito that also carries dengue fill the void left by reductions in A. aegypti? Will the dengue virus mutate (think antibiotic resistant MRSA) and become even more dangerous?–Wow, that’s like every logical fallacy wrapped together into one ridiculous statement. How is antibiotic MRSA related to dengue virus? Antibiotics only work on bacteria, and dengue is a virus.Dengue virus needs an appropriate vector to transmit itself to humans, and the symbiotic relationship between the mosquito and the virus occurred over 100 million years. Dengue cannot suddenly switch to another mosquito, like the Asian tiger mosquito which happens to actually be a much poorer vector for the virus. Besides Oxitec also has Asian tiger Frankensquitos. So there you go.

But, as you know, when anyone starts discussing how genetic engineering can actually help our lives, science gets set aside and politics matters more. Activists, using the same techniques as all science deniers, whether creationists or global warming deniers, try to create a debate that sounds scientific, but never really is. The fact is that molecular genetic engineering is more precise and predictable than older, cruder techniques like irradiation, for mosquitos.

Ironically, the SIT method, using radiation, is mostly unregulated with little or no science that supports the safety and effectiveness of SIT. On the other hand, the regulatory reviews of genetically engineered living organisms have tended to be drawn out and excessively cumbersome throughout the world, with political debate delaying or preventing approvals. As a consequence, lifesaving technology, like the genetically modified mosquitoes, becomes more expensive, and possibly may never be employed to protect human health.

Conclusion or the TL;DR version


The World Health Organization, by no means in the “pocket” of Big Pharma or Big Chemical (or Big Mosquito, I suppose)  has requested that regulatory agencies emphasize “science-based, case-by-case targeted requirements with a degree of practical parsimony,” instead of relying on “a precautionary approach that can require data to address all theoretical risks.” In other words, quit delaying technology that can help mankind because of an oversensitivity to political debates that can be largely dismissed by real science.

There are no convincing arguments, at least from a scientific point of view, that genetically modified mosquitoes pose any danger to humans, other animals, plant life, the environment, anything. However, we have boatloads of scientific evidence that shows that mosquito-borne illnesses, like Dengue fever, harm and kill human beings. We have boatloads of scientific evidence that these Frankensquitos can save lives by crushing the numbers of disease carrying mosquitos. Regulators have got to stand up for science and reject the ridiculous populist rhetoric that puts up pseudoscientific roadblocks to progress.

The elitist anti-biotechnology cult seems to have one goal in mind, and it’s not to help humanity. They want to block anything that doesn’t support their narrow-minded view of the planet–that is, by employing some Naturalistic Fallacy, or an Appeal to Nature, that the only right way to help humanity shouldn’t include biotechnology, because it’s not natural. That kind of arrogance could kill us all.

Editor’s note: This article was originally published in January 2015. It has been completely revised and updated to include more comprehensive information, to improve readability and to add current research.

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Michael Simpson

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