A Threat to Public Health: Why Killing All Mosquitoes Isn’t the Answer

Mosquitoes are deadly. Over the course of 200,000 years, mosquitoes that carry diseases have taken the lives of approximately 52 billion people on the planet. They are not stopping any time soon.

Mosquito: A Global Threat to Public Health

Annually, dengue fever, a disease caused by a virus transmitted through a mosquito bite, kills 22,000 people. About 3 billion people, or 43 percent of the world’s population, live in areas where dengue outbreaks can happen. The illness is common in more than 100 countries globally, particularly in Southeast Asia, Latin America, and Africa.

Malaria, a life-threatening illness caused by parasites also carried by mosquitoes, killed around 409,000 in 2019. That same year, the World Health Organization reported that there had been an estimated 229 million cases of malaria globally. Children under the age of 5 make up the majority of deaths (around 67 percent in 2019) from malaria.

Through a single bite of a mosquito, Zika, West Nile, and Chikungunya viruses can also be transmitted and cause an illness to a human host.

Mosquitoes have been a danger to public health for years, and experts fear that they will only worsen because of climate change. Since the mid-’80s, the Asian tiger mosquito has been spreading across the United States. The aggressive species is a vector of diseases and, unlike other pests, it is active throughout the day. Although a native of Asia, the Asian tiger mosquito has traveled over the world through shipments of flowers, bamboo, and used car tires.

Studies have warned that the population of Asian tiger mosquitoes will increase across the United States and Western Europe as the average global temperature rises due to climate change. More people, therefore, will be at risk of dengue, malaria, and other illnesses transmitted through the bite of a mosquito.

Despite the threats, there is still no vaccine available to fight and prevent the plethora of bugs mosquitoes spread. There is one for dengue called Dengvaxia developed by the drugmaker Sanofi, but it can only be given to those who had prior dengue infections. To those who have not had a bout with dengue, the vaccine is a health risk that can result in severe dengue if they are infected after inoculation.  

Should Mosquitoes be Eradicated?

The presence of mosquitoes is more than just annoying. It is a threat to health. Throughout history, it has killed billions of people. It seems that the logical next step is to completely eradicate the pests to save countless lives now and in the future.

Every year, American households already try to control the populations of mosquitoes in their properties to prevent the blood-sucking insects from biting and harming their loved ones. They do it by removing standing water in their backyards, eliminating shaded spaces, and calling experts to apply chemicals that will control and kill mosquitoes completely.

However, eliminating mosquitoes on a global scale is a different story. There are more than 3,000 species of mosquitoes on Earth, but not all transmit malaria and dengue. So, killing all mosquitoes on the planet indiscriminately will be pointless. Moreover, the disappearance of all mosquitoes will have dire consequences on the ecosystem.

Removing mosquitoes will deprive animals that eat the insects of food. There are dozens of animals with mosquitoes on their diets, including spiders, frogs, fishes, turtles, bats, and even dragonflies. Eliminating all mosquitoes is not the answer to the problem.

What Else is Being Done?

There have been efforts to target and eliminate species of mosquitoes that are known to spread diseases worldwide. Scientists have, for years, been experimenting on lab-altered mosquitoes that would neither bite humans nor increase the population of disease-causing mosquitoes in the environment.

Thousands of lab-altered mosquitoes have already been introduced in the U.S. Earlier this year, mosquito eggs were placed in areas in the Florida Keys where an invasive species called Aedes aegypti has taken hold. The goal of the lab-altered mosquitoes, which are all male, is to mate with Aedes aegypti mosquitoes and doom all female progeny to be dependent on the antibiotic tetracycline. All the female descendants of the lab-altered mosquito, therefore, will die in the wild before they lay more eggs, eliminating the population of Aedes aegypti in the area.

Other similar experiments are being done in other countries where dengue, malaria, and other illnesses caused by mosquitoes are endemic. In Singapore, male mosquitoes infected with Wolbachia, bacteria that make the insects infertile, were released in the wild. Scientists hope that it will stop mosquitoes from laying hundreds of eggs and defeat Aedes aegypti and Aedes albopictus (the Asian tiger mosquito) completely.

Fighting mosquito-borne diseases is tricky. Mosquitoes have been around since the time of the dinosaurs, and they play an important role in the ecosystem. Eliminating all mosquitoes is not the solution to the problem of mosquito-borne diseases.