Many of us have had the misfortune to encounter mosquitoes at one time or another. If we’re lucky, we’ve only experienced them from the perspective of being something of an annoyance. We see them as buzzing pests that emerge during humid periods and leave their mark with itchy bumps and welts. However, they can be far more problematic.

In tropical areas, in particular, being bitten by a mosquito can result in the transmission of a broad range of diseases, including malaria, West Nile virus, and – one of the most recently noteworthy – Zika. According to the World Health Organization (WHO), diseases spread by mosquitoes cause millions of deaths each year. While simple measures such as DEET sprays and mosquito nets can make a difference, scientists have started to explore more permanent options.

The Environmental Protection Agency (EPA) recently granted an experimental use permit to test genetically engineered mosquitoes as a way to reduce the overall population, and thereby reduce the potential for disease transmission. We’re going to take a look at how this could work, and what the potential benefits and drawbacks are likely to be.

How and Why Could Modification Work?

So, how does this work? The biotech company Oxitec has adjusted male Aedes aegypti mosquito DNA to include a protein that when passed down through breeding, kills female offspring. The goal is to eventually remove all breeding females from the genetic line, resulting in the extinction of the species. Seven hundred and fifty million of these modified mosquitoes are due to be released in Florida and Texas.

If effective, this doesn’t just mean the end of irritating pests, it has the potential to seriously reduce the transmission of blood-borne viruses. HIV is among the most harmful of these pathogens, a currently incurable immunodeficiency virus that is spread through the exchange of bodily fluids. When mosquitoes draw blood from someone infected with HIV, there is the possibility of exchanging infected blood with each new person they feed upon. Removing mosquitoes from circulation could not only reduce the potential for humans to become infected directly through bites but also the person-to-person transmission that could follow.

Genetic modification (GM) can be an ideal solution as it is far less labor-intensive than other forms of pest control. In effect, it is forcing the insects to enact their own demise through natural procreation activity. It tackles the problem at the source, rather than attempting to control the symptoms of the issue.

Genetically Modified Mosquitoes
Genetically modified mosquitoes could help disease control.

Genetically modified mosquitoes: What Could Be the Effect on the Wider Ecosystem?

From a scientific perspective, a genetically modified path to the extinction of this harmful species might well be the most practical. But we’ve also got to look at how this strategy might affect the world around us. A change in one aspect of our environment can have a knock-on effect on other elements that we may not have initially considered, as we’ve seen recently with COVID-19’s effect on wildlife due to an increased need for those in poverty-stricken areas to exploit natural resources.

In this case, we have to look at the other animals and insects that are affected by the continued presence of mosquitoes. There are few species that rely upon them as a primary source of food, but bats, birds, and fish do hunt them as part of their diet. However, it may be the case that upon removal of this species, these predators may substitute them with other insects, such as fruit flies. These might also be considered to be a pest by most of us, but their rapid reproduction cycle ensures they’re a perennially plentiful food source.

In cows, mosquito bites can result in weight loss and lower milk production, and chickens tend to lay fewer eggs too. Eradicating the species could mean that livestock is healthier, and an increase in production rates. From a domestic perspective, mosquitoes cause heartworm in dogs, which can not only be uncomfortable and detrimental to the pet’s health. It’s unlikely that genetically modified mosquitoes will be a short-term solution, so it’s important for pet and livestock owners to continue taking out adequate insurance to ensure their animals can get treatment for mosquito-transmitted pathogens.

What Are the Ethical Implications?

There’s some indication that genetically modifying mosquitoes could be effective in population control. But just because we think that it could work, does it necessarily follow that we have the right to give it a try? When it comes down to it, what we’re talking about here is using our scientific abilities to push a species to extinction. That warrants some serious consideration.

We know that mosquitoes are not a keystone species. No other plant or animal life entirely relies upon their existence. However, there’s something to be said for encouraging a diverse ecosystem. Just because we can’t currently identify a quantifiable, empirical worth of a species from our human perspective doesn’t mean that they have no value. Other animals and insects are already disappearing from our world at an alarming rate, and we don’t really know how our ability to extinguish another breed from our planet could affect this, and might this give us a license to cause the extinction of others we might deem harmful?

Genetic modification in itself is a thorny ethical subject because our decisions seem to be largely based on the precis that human life is so valuable that adjusting the DNA of other species to our benefit is justified. Reducing suffering is certainly a noble and worthy cause, but we also have a responsibility to tread very carefully, to ensure that we are not squashing the potential for life to evolve positively.


We live at an exciting time for science; we have at our fingertips the ability to explore methods that could enhance the quality of human life. Genetically altering mosquitoes in a way that they deliver their own extinction may well reduce disease transmission and cut mortality rates by a significant margin. But we must also take care to ensure we are being ethically diligent, and take time to understand the full impact of our actions.

Frankie Wallace

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