How Modified Mosquitos Could End a Deadly Global Outbreak

Luke Alphey, courtesy of the European Patent Office.

If there’s one thing that perhaps every human on earth can agree on, it is a universal hatred of mosquitos.

One of the diseases that give mosquitos the distinction of being both the most pernicious and deadliest animal in the world is dengue fever. Sufferers of dengue fever experience high fever, joint and muscle pain, rashes, and headaches; severe cases can cause abdominal pain, persistent vomiting, bleeding, and difficulty breathing.Yearly, more than 20,000 people die from the disease, in addition to up to 50 million non-lethal infections worldwide, according to WHO estimates. Though malaria is more deadly, the trajectory of dengue cases is on the uptick. Outbreaks have increased 30-fold in the last 50 years, and officials in Malaysia, Brazil, China, and elsewhere are currently facing severe outbreaks.

British geneticist and scientist Luke Alphey's plan to eradicate the dengue-carrying pests have made him a finalist at the 10th annual European Inventor Awards, held in Paris this week. Alphey uses an adaptation of the “sterile insect technique” to genetically engineer male Aedes aegypti mosquitos, rendering them infertile. When these manufactured mosquitos are released into a local population and mate with wild female mosquitos, the result is sterile offspring—and up to a 90% reduction of local dengue-carrying mosquito populations with successive releases.

Alphey’s patented method is particularly suited to dengue due to the nature of the disease, as well as the vector that carries it. Unlike malaria, which is disseminated by upwards of 10 different species of mosquito that vary by geographical region, dengue is carried by a single vector everywhere it appears, making this species-specific approach widely applicable. In addition, while there are mitigation techniques for malaria including bed nets, preventative, and therapeutic drugs, no known medical treatment for dengue exists. Bed nets don't do any good either, as carriers tend to bite during the day.

“With malaria you could find tens of vectors, different ones in different African countries versus Asia versus the Americas, so the only thing we could do with malaria would be of regional importance,” Alphey said. “If that region is Sub-Saharan Africa, that importance is still significant of course—but you don't have this one species everywhere like you do with dengue.”

Alphey in front of his mosquito breeding area.

So what happens to the environment when you take mosquitos out of it? There are 3,500 known mosquito species worldwide, and wiping them out would almost certainly affect local environments by removing prey and pollinators from complex ecosystems. (However, it should be noted, some scientists argue that the niche vacated by mosquitos would quickly be filled by other organisms.) When it comes to dengue-carrying mosquitos though, Alphey points out that because they are an invasive species in most areas of the world, except for their native regions in Africa, removing them from many ecosystems would simply be undoing what humans have introduced.

Alphey’s genetically modified mosquitos have been field-tested in Malaysia, the Cayman Islands, Brazil, and Panama. The invention’s first commercial client is on track to be CTNbio, the Brazilian agency in charge of regulating GMOs, which has completed final technical approval for commercial registration.

It’s hard not to view Alphey’s invention as Darwinism at its most manipulative. Indeed, genetic engineering isn’t a popular concept across fields, as demonstrated by the recent backlash to China’s success at editing non-viable human embryos. However Alphey explains that it’s important to view genetic engineering—be it food, medicine, or humans themselves—in the right context.

“I think food has a sort of special place in our culture and people want it to be natural, there’s confusion about what that means,” Alphey said. “But health for most people is the opposite. We want our hospitals to be clean, sterile, sharp instruments, flashing lights as far away from a cave as possible … So now all the people that were going out spraying chemicals, can now go out and release sterile mosquitos.”