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A Caution Against Current Transgenic Mosquitoes

By Rohan Akash Narayanan | Position Paper

     It was a couple of years ago when I had my first truly troubling experience with the family Culicidae. Of course, mosquitoes have been a constant annoyance in my life, making me itch ever since I was little. However, I had never contracted an illness from these small flies. It was only when my little cousin, age 9, caught Dengue fever while on a family trip to India that I got to witness one of the many pestilences mosquitoes transmit first-hand. Seeing him in excruciating pain and running an incredibly high fever was scary to say the least. What was more terrifying was that if we were unable to get my cousin appropriate treatment, like so many others in the region are unable to do, he would have suffered an agonizing death. It was at that moment that I began to understand the incredible challenge that people in developing countries face under the cloud of these prolific and deadly insects.

Luckily for us, the medical field has made leaps in the treatment of mosquito-borne diseases. Simply put, the lethality of these illnesses has been drastically reduced since their discovery. However, despite these advancements, many developing countries still suffer greatly because they do not possess the same access to resources as the nations that make up the G7(US, Canada, etc.). One possible solution that has been brought into the public consciousness is the use of genetic modification technology to curtail the threat that these bugs pose. However, despite my cousin’s near-death experience, I advise caution before deploying GMO mosquitos to assist in improving public health. Simply put not enough research has been done concerning their potential to cause harm to our already taxed environment, the species which reside in them, and ourselves.

            In this paper, I will argue against the utilization of genetically modified (GM) mosquitoes as a solution to this burgeoning global health crisis. I will begin by presenting background on the topic, namely the reasons why scientists are investigating this avenue of research and the current health problems affecting many developing countries. Next, I will present reasons why introducing these bugs, in their current state, may cause more harm than good and that this is an area of science with extremely minimal research. Lastly, I will refute the two extreme positions on this issue, those who are strongly in favor of genetically modified mosquitoes and those who are ardently against the use of this potentially useful technology. I will conclude by providing preliminary steps that should be taken to confront this global health crisis.

In order to engage with this topic properly, we must first understand that our ability to modify organisms is not new or radical. Our concerns are with the technology being used too early in its development, not about the ethicality of our ability to create artificial genes. In a paper discussing the history of genetically modified organisms, Dr. Bruce Chassy, from the University of Illinois at Urbana-Champaign, details the present and the past of certain GMOs. He states that “over the millennia agriculturalists domesticated crops and animals to suit the needs of improved production, resistance to disease/pests and to serve human preference” (Chassy). Now that we have demystified the concept of the transgenic organism, we can view it within the context of the GM mosquito. Here we are attempting to do something like what our species has historically done; we are changing an animal to serve human preference. However, we are undertaking this task in a particularly challenging and delicate setting. Manipulating the genes of a dog, an animal with very few direct ecological implications, is a rather harmless act. But mosquitos occupy a niche that is lower on the ecological food web, meaning that many different animals incorporate them as part of their diet. Many fish, insect and bird species all consume mosquitos either as larvae or as adults. Modifying these animals to yield infertile young has the potential to cause a trophic cascade, affecting the feeding habits, behavior, and habitat of the many species that utilize these insects as a food source. Yet, despite predation from numerous sources, mosquitoes remain quite prolific and are extremely fecund. It is then not surprising that we have found several non-ecological ways of controlling these pests over our long history.

            Currently, mosquito-borne illness is controlled in two ways. Countries across the world apply a similar tactic when it comes to population control, authorities utilize pesticides like DDT. However, more developed countries have better healthcare systems and more accessible treatment options to those individuals that become infected. In a paper published by the Medical Research Council of Zimbabwe, scientists talk about mosquitos as a disease vector and the challenges surrounding traditional population control methods. The paper states, “dilemmas in malaria research have extended to other areas. A case in point is the use of DDT which pits humans against the environment” (Ndebele et al.). The paper then goes further to say, “It is now a requirement that a proven standard should be provided as an alternative method to the study community” (Ndebele et al.).With global insect populations, ranging from pollinators to pill bugs, on the decline, we must take into consideration the ecological ramification of this type of maintenance structure.

            The reasons for applying this chemical are, however, justified. According to the World Health Organization (WHO), malaria alone had caused approximately 438,000 deaths in 2015(WHO). Sadly, most of these deaths occur in countries where treatment is oftentimes either not an option or quite difficult to get. Nonetheless, this issue isn’t one simply reserved for third-world countries. The Center for Disease Control in the US reports, “illnesses from mosquito, tick, and flea bites have tripled in the US, with more than 640,000 cases reported during the 13 years from 2004 through 2016” (CDC). While malaria has been mostly eradicated in the continental US, west nile, chikungunya and most recently zika have all appeared within the states. Globally these mosquito-borne diseases have all contributed to the ever-growing death toll, resulting in millions of casualties worldwide (WHO). Recently in Malaysia, dengue fever has been infecting individuals at an increasing rate namely due to traditional control methods being ineffective in combating the virus.

     Since conventional methods have proved useless, this event has prompted many scientists to investigate a genetic solution. In a paper co-authored by 20 scientists (namely because those who cultivated the modified organisms and managed them in the field were included in the authorship), the team details their experiences with one of the first open field releases of GM mosquitoes. In the opening of their paper, they write, “In the absence of specific drugs or vaccines, control focuses on suppressing the principal mosquito vector, Aedes aegypti, yet current methods have not proven adequate to control the disease” (Lacroix et al.). Overall, the testing went well but did not yield results significant enough to warrant its use on the global scale. We must also be extremely careful when dabbling in this technology, only female members of Culicidae drink blood; meanwhile, males drink nectar using their proboscis as a straw instead of a hypodermic needle. In doing so, they act as important pollinators for their local environments. With pollinators like bees on a major decline, we don’t quite know what will happen if another prolific pollinator is rendered sterile.

Despite this study and its moderate success, it is one of the few to ever be conducted. In a structured cost-benefit analysis on transgenic mosquito release, former director of the council for scientific and industrial research of South Africa Jane Morris writes, “few comprehensive studies have been undertaken to evaluate the impact of the release of transgenic insects or other related technologies” (Morris). Despite the paper being written before the prior experiment being conducted, it really shows just how new and unexplored this field of science is. When exploring this vein of science, we must tread carefully. The last thing we want is to create a potentially more dangerous strain of the various mosquito-borne ailments. Just as hand sanitizers have bred bacteria more durable than their predecessors, genetic manipulation of mosquito salivary glands or their fertility may potentially cause diseases like malaria, yellow fever or dengue to mutate and either find new vectors for infection or increase their lethality. This exact problem has occurred in the realm of GM plants. Some modified crop species are designed to poison the typical pests that hinder their growth, in response, these pest species have evolved to metabolize these new toxins. Nature’s response to our meddling is incredibly hard to predict, and if we are not cautious who knows what we could create as a byproduct of our actions.

Additionally, we’re not entirely sure how effective these mosquitoes are when introduced and bred with their wild counterparts. According to the study conducted in 2016, after the Malaysian study, scientists show that they understand that the “persistence of transgenes (man-made genes) in the environment is a consideration in risk assessments of transgenic organisms” (Valerio et al.). The effectiveness of this expensive undertaking is very important when addressing this issue. If the transgenic insects aren’t properly spreading our engineered genes to their progeny, then what would the point of this whole project be? We are attempting to find a solution that will not only be environment-safe but also one that will be more effective in regard to population control. The conclusion of this paper is quite indicative of the work scientists need to undertake to make this a truly viable option. This team found that “the period before ovipositions that contained no transgenic progeny ranged from as little as three weeks after cage initiation to as long as 11 weeks” (Valerio et al.). In such a small window, genetically speaking, the engineered genes disappeared from the mixed wild-type and transgenic lab population. If this is going to be our long-term answer to the mosquito issue, we first need to improve the viability of these genes when exposed to the wild unedited genome, otherwise why even commit to this action?

Some individuals, however, are convinced that this technology should be implemented immediately. In an interview given to the Yale School of Forestry & Environmental Studies

Tom Miller, a former professor of entomology at the University of California, Riverside, says that the genetically modified mosquitoes Oxitec uses to control dengue should not be regulated at all (Palmer). Unregulated genetic manipulation is a scary thought and this idea sets a dangerous precedent. If we simply permit large-scale biotechnology companies, like Oxitec, to churn out various Culicidae strains, who knows exactly what they might do? Leaving these technologies unregulated on even a national level has proven to be detrimental to those that the innovation is attempting to aid. A cautionary tale lies in the realm of GM plants, primarily back when Mon Santo and other biotech companies like Bayer became an effective monopoly on the sale of transgenic seeds. Furthermore, despite these edited Aedes aegypti mosquitoes obtaining an overall 90% population reduction in areas they have been previously deployed, we continue to be clueless about their true ecological implications and the likelihood of their diseases mutating (Palmer).

            On the other side of the aisle, we find people who stand firmly against the concept of GM anything. Over recent years, there has formed a certain stigma around anything remotely associated with the words “genetically modified.” However, the opposition's platform of transgenic organisms being inherently bad falls apart very quickly. After all, nearly all our livestock and crops are GMOs. Forbes contributor Kavin Senapathy writes, “GMO is practically impossible to define, at least in a logical way. Nearly every single plant and animal humans consume has had their genes (which contain the DNA molecules that code for each organism’s structures and functions) altered well beyond nature's jurisdiction” (Senapathy). Furthermore, genetic manipulation technology is not something we should simply abandon. There are bound to be many useful, yet undiscovered uses for gene manipulation. Jane Morris writes, “As long as individuals and societies focus only on risks, there is a danger that potentially beneficial technologies will not be introduced, the resulting inaction putting a brake on development” (Morris). There will come a point when the science is in, on the topic of transgenic mosquitoes, and when that day comes only then should we engage with the technology on a global scale. Despite today not being the day, we should not simply abandon this technology.

            On our already worn planet, we must be extremely careful when deciding to release a creature of our own design. Currently, we sit in what is known as the 6th extinction. Hundreds of species go extinct every single year, and here we are poised to send another down that road. If we are to undertake this bleak task, we must at least make sure that the technology we implement is stellar and will not create an even bigger shockwave within the environments of Earth. More research needs to be conducted, like the field test in Malaysia, to confirm that this solution is one that will not change the local ecology but also ensure that the transgenes input into these modified insects will not only work but prompt unknown genetic mutation within the population. Let us not be too hasty nor too recalcitrant when faced with this revolutionary technology. But instead, be patient and allow the scientific process to work out the kinks before we commit to releasing these bloodsuckers across the globe.






Works Cited

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