Intentional extinction? Scientists experiment with eliminating mosquitoes to combat disease

It might be hard to find many people who are willing to defend the life of the mosquito buzzing around your living room on a cool summer night, but for the most part, civilized society tends to lean away from the intentional extinction of a species. The world’s ecosystem didn’t develop for the sake of our human comfort, and each creature (whether beast or pest) has a role to play in the great “circle of life” we all learned about as kids in science class.

It can be extremely difficult to predict what second or third order effects removing a species from an ecosystem can actually have. The variables tend to spread far beyond the immediate concerns about the food chain that first comes to mind. However, there’s a sizable contingent of scientists who believe eliminating certain species of mosquitoes (or reducing their global population to near extinction) may not have that detrimental of an effect on the overall ecosystem. If that is the case, eliminating some species of mosquitoes could mean a lot more than getting to skip the DEET before you go on your hike.

According to the World Health Organization, the effort to control the spread of malaria, perhaps the most famous of mosquito-borne illnesses, will cost something in the neighborhood of $2.5 billion a year by 2025. Add in infection case management and program support, and the estimate climbs to $3.3 billion for the same year. Under President Trump, the United States invested $961 million for global malaria prevention in 2018 alone, but reported cases of infection continue to rise. In 2017 (the most recent year with figures to pull from), malaria cases increased for the second year in a row, with 219 million infections and 435,000 dying as a result.

In 2016, a study showed that mefloquine, a medication that was once commonly prescribed to U.S. troops deployed to areas with high malaria infection rates, can cause brain damage and lead to other serious medical conditions. In 2016, a reported 57 U.S. service members contracted malaria, despite significant prevention efforts. Mosquitoes aren’t just disease carriers and a drain on the global economy, they’re even a threat to military readiness.

So what can we really do about them?

Conventional methods of pest control have done little to stop the spread of mosquito-borne illnesses like malaria or Zika, which is why some scientists contend that using gene editing to “infect” mosquito populations with defects that would prevent them from feeding or breeding is the most logical answer. In effect, scientists would use CRISPR gene editing techniques to infuse mosquito larvae with the desired mutations. Those mosquitoes would then be released into the wild to procreate with the existing population, allowing the mutations to manifest in subsequent generations, preventing them from being able to feed or breed.

Whether or not it’s possible to eliminate an entire breed of mosquito is subject to some debate, but no one disputes that this method could dramatically reduce the population in local areas. The question then is, at what cost? That’s exactly what a group of scientists in Italy are hoping to answer. They’ve created sealed environments that resemble natural ecosystems into which they can release gene-edited mosquitoes. Once introduced, they can observe the effect of the experiment on not only the mosquito population, but on the surrounding ecosystem as well.

Of course, no laboratory setting could actually mirror an entire ecosystem, so there’s still a great deal of risk involved even if their plan proves successful.

But then, there seems to be a fair amount of risk involved in keeping mosquitoes alive, too.