I was warned there would be a lot of mosquitoes when I traveled to the northern coast of Alaska to collect soil samples, but nothing could prepare me for the swarms of bugs that darkened the sky above me as I worked. The pages of our field books were littered with insect corpses crushed whenever we closed them. Even though they couldn’t bite through my head net and spray, they still managed to make life pretty miserable. It’s no wonder they can drive caribou seeking relief, like billions of little sheep dogs, into new landscapes.
Relatively speaking, the Arctic gets off easy compared to other parts of the world. Since Arctic mosquitoes do not transmit any known diseases, the worst I could expect from a bite is a minor itch. For half of the world’s population, avoiding mosquito bites is a matter of life and death.
It is the mosquito’s ability to transmit diseases that has earned it the reputation of deadliest animal on earth—a statistic popularized by Bill Gates. Malaria alone infects more than 200 million people a year. Nearly half a million die. Besides malaria, mosquitoes are responsible for spreading dengue and yellow fever, encephalitis, filariasis, West Nile, and increasingly, Zika virus.
To make matters worse, human populations are increasing near mosquito habitats. Combine this with the ease of international travel, and we can expect rare and obscure diseases will continue to make news as they spread around the world.
It’s tempting to ask the extreme questions. BBC asked, “Would it be wrong to eradicate mosquitoes?” In June 2016, Smithsonian reported on new research considering gene editing technology that could, in theory, wipe out mosquitoes. “Should they use it?” it asked. Slate pulls no punches with their headline: “Let’s Kill All the Mosquitoes.” National Geographic was less dramatic but asked all the same, “Are Mosquitoes Necessary?”
In Christian circles, a similar sentiment can be expressed another way: Why did God create mosquitoes? Many of us don’t quite see the point of letting the little buggers live. In light of this challenge, what is our responsibility to mosquitoes, mankind, and the earth?
Mosquitoes are a victim, too
Mosquitoes live on flower nectar for most of their adult lives. Although this fuel of diluted sugars is readily available and a reasonably good source of energy, it is nutrient poor and lacking in protein. Still, nectar can power a male mosquito for his entire life. The same can’t be said for a female mosquito. To lay eggs, she needs a jolt of vitamins and protein that nectar can’t provide. Instead, she turns to an alternative energy source: us.
In many tropical regions, when a mosquito bites, she can give as well as receive. As she takes in blood, a mosquito may deposit parasites, viruses, or bacteria directly into our blood streams. Mosquitoes act as vectors when they transport these pathogenic organisms to an animal where they can grow or reproduce. Mosquitoes are unwittingly the carrier for disease, having no intention of ill will.
“One must remember that a mosquito is a victim of [Plasmodium parasites that cause malaria] just as we are. There is not any direct benefit known that mosquitoes draw from the parasite,” explained Francis Muregi, a Kenyan university lecturer and malaria researcher.
Additionally, not all mosquitoes are the same. Some mosquito species only bite amphibians, while others only bite reptiles. Some don’t bite anything, while others can lay one set of eggs from energy reserves but need to take a blood meal to lay additional broods. Still, there are plenty of species that will make use of birds and mammals to experience the miracle of motherhood. Not all mosquitoes deserve the blame as deadliest animal.
Is eradication the only option?
Malaria has been especially difficult to combat. The Plasmodiam parasites—of which there are five infecting humans—have become resistant to many of the medications used to eliminate it from a victim’s blood. Meanwhile mosquitoes have developed resistance to insecticides used to reduce its population. Scientists are increasingly attempting to develop newer technologies that wouldn’t just reduce mosquito populations but decimate them.
Discovered in 2012, a breakthrough in genetic technology called CRISPR-Cas9 promises to revolutionize medicine and agriculture. The method can introduce new genes in a species with near perfect accuracy compared with older methods.
As reported by Smithsonian, one team in Europe is experimenting with the method to insert a lethal genetic mutation into a generation of mosquitoes. When paired with a “gene drive” that would skip the ordinary process of inheritance by copying the mutated gene onto both chromosomes, ensuring the gene gets passed on, an entire breeding population of mosquitoes could be completely wiped out.
Muregi has seen firsthand the damage malaria can do and wouldn’t hesitate to kill all mosquitoes if that were the only option. “I believe God allows us to subdue our foes, and vectors [mosquitoes] are unwittingly used by pathogens to harm us. It would be better to have all mosquitoes dead than one child dead.”
Mosquito-borne diseases kill close to 750,000 people each year, according to the World Health Organization.
Setting mosquitoes free
If God believes that we are worth more than many sparrows (Matt. 10:31) then surely millions of us are worth more than mosquitoes? Yet we know that God made all creatures in his wisdom (Ps. 104:24), and even mosquitoes are waiting for redemption (Rom. 8:21). Ecosystems work together in a certain way, so removing mosquitoes may have an impact we can’t anticipate.
Consider the mosquitoes’ role in the Arctic food chain as a catalyst to keep caribou moving. Alaskan caribou travel in herds measuring tens and even hundreds of thousands strong. These animals graze on slow-growing lichens, shrubs, and sedges. Were they to linger too long in one area, they could overgraze it and create lasting damage. Instead, clouds of mosquitoes drive the herds to the cold, windy Arctic coast where the mosquitoes can’t follow.
In areas like sub-Saharan Africa, mosquitoes are part of a much more complex food web. Insects and animals that feed on mosquitoes in biodiverse ecosystems could likely find alternative food. However, removing them from this context—though it would make human lives easier—would still make the ecosystem more vulnerable.
Could their elimination create enough good for humans that it justifies a minor loss of function in the ecosystem?
Muregi feels that eliminating the parasite would be preferable “if we are able to kill the parasite without harming the mosquito.” His own research aims at finding drugs capable of delaying or avoiding the resistance Plasmodium parasites have developed to current drug therapies.
Solutions that lean toward control without eradication could still save many lives, though not all are equal. For example, one by the British company Oxitec aims to kill (but not annihilate) a local population annually, while another by a nonprofit called Eliminate Dengue attempts to fight the parasite infecting mosquitoes.
Science reported, “If Oxitec’s mosquitoes are on a suicide mission, Eliminate Dengue’s are missionaries, designed not to wipe out wild mosquito populations, but to transform them.”
In April 2015, a small city in Brazil became the first to combat dengue fever using genetically modified mosquitoes, releasing lab-born designer mosquitoes from Oxitec. The genetic approach, which predates CRISPR, breeds male larvae with a lethal mutation. When released, the altered mosquitoes mate with wild mosquitoes and produce offspring that die before reproducing. The method doesn’t use a gene drive, so it will have to be repeated; but it could reduce a local population by 90 percent.
Another method by Eliminate Dengue sets mosquitoes free from the parasite by infecting mosquitoes with a different parasite called Wolbachia. The bacterium appears to compete with dengue and chikungunya viruses or aid in triggering the mosquito’s immune system. The approach, funded by the Gates Foundation, has been released in local populations in five countries.
It still stands to be known whether either solution will significantly reduce cases of mosquito-borne diseases. It only takes a few mosquitoes to start a local outbreak.
Christians can look forward to a day when we have a new heaven and new earth where there will be no conflict between doing what is good for humanity and what is good stewardship of creation. Until that time, with God’s grace, we must do our best to balance these two needs.
Jeremy Lederhouse is a technician in the environmental sciences division at the Argonne National Lab in Illinois.