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Science may use extreme measures to control mosquito populations

Not many animals are less loved than the mosquito.  In Native American myths, mosquitoes are tricksters.  In West Africa, one myth tells why mosquitoes buzz in people’s ears.  Another myth, recounted on PACEsetters, tells how a blessing given by a mystical encounter with ancestors was swapped for a package full of mosquitoes.

People play games to see how many mosquitoes they can kill.  I kill any mosquito that happens to land on me or anyone I care about.  We hose ourselves down with toxins, light candles and burn smelly incense coils to keep mosquitoes at bay.  We screen our windows and our tents to keep out the bloodsucking fiends. In his book, The Animal Dialogues, Craig Childs tells of one man in Alaska in desperation spraying himself with Raid to keep mosquitoes off.  Terms like ‘blood sucker’ refer to the worst types of humans, parodying them to mosquitoes or vampire bats. Mosquitoes are tenacious and always seem to be hungry, at least in the summer.    

According to National Geographic, there are 3,000 species of mosquito world-wide; they’re also said to be the animal that’s spread more disease than any other.  Only about 200 species of mosquito actually feed on humans. Malaria, Yellow Fever, Dengue Fever, Zika Virus, even West Nile are all transmitted via mosquitos.  According to the World Health Organization, there were approximately 212 million cases of malaria in 2015, resulting in 429,000 deaths.  It’s clear from those numbers alone that malaria from mosquitoes by itself poses a real threat, besides the other illnesses the insects carry.

It’s the stark facts of mosquito borne illness, the death, the widespread illness, that have led some to call for the all-out extinction of mosquitoes.  It isn’t just itchy bumps for many living in the tropical regions of the world. It’s not too much surprise that scientists have been trying long and hard to limit mosquito populations.  

UC Santa Cruz News Center reported in 2016 that mosquito populations have increased by tenfold in New Jersey, New York and California over fifty years.  The increase in mosquito populations is said to be due to increased urbanization as well as smaller concentrations of DDT in the environment.  DDT was once a common pesticide in the US, and Time reported that it was even vital to protecting allied forces from diseases such as malaria during World War II.  The pesticide was ultimately banned in the US and many other countries because of its negative effect on human and animal health.  Banning DDT has helped raptor populations to rebound in particular because it left the bird with dangerously thin egg shells that often broke before hatching.  

Not only has DDT historically been a health and environment risk but over time mosquitoes can evolve resistance to the pesticide, limiting its effectiveness.  This leaves scientists trying to discover novel ways to limit mosquito populations of their ability to spread disease. reports that last summer, 20 million male mosquitoes infected with Wolbachia bacteria.  When the infected male mosquitoes mate with females, the females lay eggs with dead embryos never to hatch.  The idea is to cut mosquito populations down when offspring fail to hatch. The species of mosquito infected with Wolbachia doesn’t usually carry it but 40% of insects overall do and the bacteria has the added benefit of stopping infected mosquitoes from transmitting diseases like Zika.

Another more extreme method of mosquito control relies on directly modifying mosquito genes.  An English company, Oxitec, has modified mosquitoes with a gene that kills mosquito offspring after only two or three days from hatching.  Oxitec recently proposed testing its new technology in Key West, Florida. Journal Sentinel reported that many local residents were not in favor of the test.  In the end, the project was stalled last summer because of political opposition to the tests but Oxitec remains hopeful that future tests may go forward.  A local doctor in Key West pointed out that the mosquitoes used in trials require access to an antibiotic to survive and expressed concern of an increase in antibiotic resistant bacteria left in the mosquitoes wake.

According to Global Research, the EPA has approved the release of wolbachia GMO mosquitoes in 20 states.  The Oxitec mosquitoes remain un-approved.  The technology of editing genes, creating genetically modified organisms (GMOS) has increased rapidly, giving humans what seems like an almost god-like power.  The possibility that someday soon humans might have the power not only to control mosquito populations but wipe completely destroy them looms large.  In 2016 a Guardian headlineasked, Should we wipe mosquitoes off the face of the Earth?  The question continues to be asked with increasing urgency as biotech companies continue to develop ways to control and destroy mosquitoes.

Mostly it’s a one sided argument.  Most people that have doubts are concerned about the fallout of killing mosquitoes off.  There is concern for the potential health risk of GMO mosquitoes and the environmental impact of killing them off.  

There is extremely little consideration for the mosquitoes themselves but it’s good to remember that killing off wolves, coyotes, bears and other dangerous predators was popular at one time.  The Guardian even quotes E.O. Wilson, famed conservation biologist as being for the extinction of mosquitoes that spread malaria (Anopheles gambiae), “Keep their DNA for future research and let them go.”

I myself am torn over the idea of killing of mosquitoes.  I’ve visited tropical Africa twice and lived in close proximity with locals for months at a time.  Malaria and other diseases routinely kill people and often the locals don’t have the luxury of even going to a doctor and getting a diagnosis of the disease taking their life.  I as a traveler in the tropics have always been able to take prophylaxis medicines preventing me from getting malaria and a vaccine for yellow fever. It’s largely a mistake of being born in a wealthy nation that I am able to visit Africa, Asia or South America in relative safety instead of suffering and dying of tropical disease.  

It’s easy to see why nations like India would be quick to embrace the complete eradication of disease bearing mosquitoes.  It’s also to see why residents of places like Key West, Florida where most tropical diseases no longer pose a threat would be wary of GMO insects being released for any purpose.  What are the long term consequences of killing off mosquitoes?

Fish, other insects, amphibians, birds and bats all feed on mosquitoes.  It’s not hard to imagine mosquitoes globally being an important source of food as well with their prevalence.  Some studies, like one discussed in Nature’s news feature shows that eradicating mosquito species would have little ecological impact.  The truth is, it’s extremely hard to know the overall impact of mosquitoes or their eradication on the world today.  Mosquitoes are everywhere and small, their interactions with other animals and the physical environment are complex and difficult to quantify.

The people who would stand to benefit the most from the death of malaria carrying mosquitoes are some of the poorest in the world.  People living in tropical nations from Africa and South America to Asia could be saved from horrible disease that ravishes them. Still, there are many more problems in these areas such as food insecurity, deforestation, war and political insecurity.  It’s hard to know if destroying malaria or it’s insect hosts will truly help these people in the long run. But who am I to suggest denying the people of the tropics a chance at a better life?

I’m reminded of a recent trip I made with my fiancé, Erin, to Padre Island National Seashore.  Erin was walking one of our dogs and had a brief conversation with a man camping near us. The man told Erin that years before when he’d visited the seashore, there had been a lot of mosquitoes at the same time of year.  When we visited, none of us encountered any mosquitoes. The man was a little disturbed by the lack of pesky insects. “Mosquitoes are guardians of wilderness,” the man told Erin.  

The comment seems prophetic at this moment when humans are gaining enough power to potentially destroy one of the wildest and least comfortable parts of our world.  If we eradicate even one mosquito species from earth, we destroy earth as it is now and usher in a new world. We have no idea in reality how the new world we’d create operates or how to live well in it.  We forget that this world, the one we live in created us, not the other way around. Mosquitoes have been on this planet for as much as 90-100 million years, longer than primates, much less than humans have been around.  Mosquitoes shaped the world we were born into and the human species as well.  We should tread carefully.

By Zach Fitzner, Contributing Writer    

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