All Buzz, No Bite: The Good and the Bad of Genetically Modified Mosquitoes

By: Christian Natanauan (Ikirara)

For hundreds of years, the Aedes aegypti mosquito has conreacccontinued to plague the global populace, reaching an astounding estimate of 23 million cases from 1980 to 2017 from A aegyptiborne dengue alone. The humble yet deadly stinger-killer is a primary vector of arboviruses most commonly dengue, chikungunya, yellow fever, and Zika viruses, and is native to African, Asian, and South American countries

With recent efforts and breakthroughs in the control of A aegypti and the prevention of its related diseases, one such fascinating method was the use of mosquitoes genetically modified to “kill” its own kind The project, streamlined by biotechnology company Oxitec, has been initiated through field trials as early as 2009, leading to its peak in 2021 through the release of said GM mosquitoes into selected research areas

The genetic basis involves the insertion of two genes that contribute to the production of the OX513A strain in A aegypti eggs: a self-limiting tTAV (tetracycline repressible transactivator variant) gene that prevents the maturation of female offspring, and a red fluorescent marker gene for the detection and identification of genetically engineered species and their offspring. The resulting OX5034 modified male wrigglers would then grow and are allowed to mate with normal female A aegypti, the main biters and transmitters of viral infections. The death of consequent female offspring indicates successful genetic modification of male mosquitoes, leading to an expected result of a decreased total in the adult mosquito population after a certain period of about 10 generations.

The abovementioned system was patented by Oxitec

Oxitec as the “Release of Insects carrying a Dominant Lethal” or RIDL system, which is envisaged to control mosquitoes with zero to little use of chemical insecticides, wherein repeated use has led to the development of resistance by modern generations of mosquito species in certain regions. Following the release of transgenic A aegypti into selected areas, significant reductions in mosquito populations have been reported, reaching an approximately 79% decrease in a field test held in Indaiatuba, São Paulo, Brazil last 20182019 The 2021-2022 openair study in the Florida Keys, USA, was also reported to exhibit positive results, though official findings have yet to be published as of writing

Multitudes of appraisals from the scientific community have since been garnered due to the success of the project based on statistics and nusdf numerical data alone, but a plethora of concerns have also been constantly raised against the widespread release of genetically modified A aegypti.

Before the release of the OX5034 mosquitoes in the Florida Keys, numerous setbacks have arisen due to apprehensions of the local citizens since its announcement in 2011 Despite having no risk of causing genetic modification in humans, the lack of education in genetically modified mosquitoes and other organisms has led to worries about residents getting bitten. Ultimately, the project was approved by state and federal authorities last 2020, though being limited to the Florida Keys area instead of the larger portion of Southern Florida.

The earliest field trials were held in Grand Cayman, Cayman Islands in 2009, but has since ceased operations in 2018 due to various issues. Foremost of these concerns are with regards to cost-benefit analyses, wherein an enormous amount of 2.8 million modified adult males needs to be released per week for them to only lead to a reduction of 20,000 wild-type mosquitoes in the area Moreover, constant funding would also be required for maintenance and control since a decrease in release in the main field site has led to the eventual resurgence of mosquito populations— thus, a delineation from the project’s main goal Adding to these concerns are the limited number of results being published and made available for peer assessment

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Similar concerns have also been faced in the nowabandoned field test in Malaysia, wherein only a small number of about 6000 modified mosquitoes have been released. Therefore, results were not publishable due to the lack of significant results of population suppression due to an inadequate amount of transgenic A aegypti adult males.

While having received the most successful results in the project conducted in São Paulo, Brazil, professionals have criticized Oxitec due to issues regarding poorquality risk assessments and public transparency. Risk assessment documents were submitted three years later than the implementation of the open field test in 2011. Independent field tests have also revealed the occurrence of genetically modified females that have survived maturation and thus contain genomic information from the transgenic mosquitoes, further leading to more biological concerns that have failed to be accounted for in initial risk assessments. Despite having no data to affirm or disprove the effectiveness and dangers of these GM adult female mosquitoes to the bitten humans, authors of Oxitec research studies have since published speculative inferences regarding the results, misleading readers towards positive conclusions without reputable data to support such statements

Moreover, the lack of transparency leads to the failure of communicating the risk factors to participants and local citizens, adding to the ethical problems that surround the OX5034 mosquito project

The environmental release of a genetically modified organism is also sure to create a huge impact on an experimental area ’ s ecosystem. The drastic reduction in wild-type mosquito populations could disrupt the local food web, affecting organisms that rely on mosquitoes as an important food source. The hypothetical eradication of mosquitoes also cannot ensure the overall transmission of mosquito-borne diseases since the mosquitoes may conveniently migrate into areas that neighbor a specific field test site

With all points made, this begs the question: is the release of genetically modified A aegypti worth it for the eradication of mosquito-borne disease While prelimina numerical data point positive impacts on publ health, such projects mu first take in consideration the vario biological, ethical, an environmental spher before kickstarting the fruition

In a local context, th Oxitec mosquito proje may provide a hug benefit for lessenin dengue and oth arbovirus cases in th Philippines, but the cost- effectiveness and ecological impact of its implementation would just lead to more issues that a third-world country may not yet afford. Following the World Health Organization’s position statement regarding the matter, once a stepwise approach involving the conductance of risk assessment, application for regulation by authorities and appropriate regional surveying; the engagement, education, and communication with local communities regarding the impact of genetic modification and GM-related projects; and proper procurement of funding and manpower for the execution of the project has been attained it is only then that the benefits of genetically engineered mosquitoes can be reaped, a goal that currently seems far to reach. Genetically modified mosquitoes are surely a testament to the progression of biological research and a step forward toward the advancement in the lessening of mosquitoborne disease cases What proves to be a buzzing challenge to the research teams is the proper execution of these projects that lessen their risks to humans and the environment, heeding the calls and concerns of the scientific community to move towards more inclusive and sustainable efforts toward global public health response