11/06/2026

LYFE THURSDAY | JUNE 11, 2026 21 What if we killed all mosquitoes?

T HE deadliest animals are not lions, spiders or snakes but the tiny mosquitoes that suck our blood, make us itchy and infect us with disease. Mosquitoes kill around 760,000 people every year, according to research site Our World in Data, with humans ourselves coming a distant second. This is because mosquitoes account for 17% of all infectious diseases, including malaria, dengue, yellow fever, chikungunya and Zika. And as the world warms due to human-driven climate change, mosquitoes are roaming to new areas during longer summers, raising fears they could propel future health crises. So how can humanity fight back against our greatest foe? Is there a safe way we could eradicate these killer mosquitoes – and how bad would that be for the environment? #notallmosquitoes First, we would not need to vanquish all mosquitoes. Out of roughly 3,500 mosquito species, only around 100 bite humans. And just five species are responsible for roughly 95% of human infections, Hilary Ranson, a Liverpool Tropical Medicine School vector biologist told AFP. On balance, Ranson felt losing five mosquito species “could be tolerated given the huge devastation” they inflict on the world, from mass death to crippling economic fallout. Dan Peach, a Georgia University mosquito entomologist, broadly agreed but emphasised more information was needed to compare eradication with the alternatives. Environmental impact The five disease-spreading mosquitoes “have evolved to be very

o Experts debate consequences, necessity of eliminating planet’s deadliest animals

When scientists tweaked females of malaria-carrying Anopheles gambiae mosquitoes to make them infertile, it wiped out a population in the lab over just a few generations. Target Malaria, funded by the Gates Foundation, has not yet tested gene-drive technology in Africa but plans to carry out a trial in a malaria endemic country by 2030. However Target Malaria was dealt a blow last year when Burkina Faso’s military-led government ended separate testing involving genetically modified mosquitoes in the country, where it had been criticised by civil society groups and targeted by disinformation campaigns. Another strategy involves infecting Aedes aegypti mosquitoes with the bacteria Wolbachia. This can crash their population – or simply reduce their ability to transmit dengue. This raises another question: Do we actually need to kill them? Defanging mosquitoes When Wolbachia-infected sterile mosquitoes were released in the Brazilian city of Niteroi, there was an 89% drop in dengue cases, research showed last year. More than 16 million people across 15 countries have now been protected by these mosquitoes with “no negative consequences”, Scott

closely associated to humans”, including feeding on and breeding near us, Ranson explained. This means eradicating them would not have a major impact on the broader ecosystem – and other, genetically similar but less deadly mosquitoes would likely quickly “fill that ecological niche”, she added. Peach was not convinced we know enough “about the ecology of most mosquito species to be confident one way or the other, but I also think that it is okay to acknowledge this and still proceed”. Mosquitoes do “transfer nutrients from their aquatic larval habitats” to other areas and serve as food for insects, fish and other animals, he said. They also pollinate plants but this “isn’t well understood and may vary by species”, Peach added. Ranson acknowledged there is a valid debate over the ethics of humans committing “specicide” while pointing out we are currently unintentionally wiping out a huge number of species. How to wipe mosquitoes out One of the most prominent new technological options is called gene drive, which involves genetically modifying animals so that they pass down a particular trait to their offspring.

A dead Aedes aegypti mosquito is seen at a laboratory of biotech company Wolbito do Brasil.

O’Neill, World Mosquito Programme founder, said. Meanwhile, a project called Transmission Zero is trying to use gene-drive technology to make it so that Anopheles gambiae mosquitoes no longer spread malaria. Lab research published in Nature late last year suggested the scientists are getting closer to this goal with the team planning to launch an in-country trial in 2030. The Burkina Faso setback showed these projects must have some “political support or buy-in” from the countries where they are tested, study author Dickson Wilson Lwetoijera of Tanzania’s Ifakara Health

Institute said.

No ‘magic bullet’ Rather than just relying on a technological “magic bullet”, usually funded by the Gates Foundation, Ranson called for a more “holistic solution” for these diseases. This would require giving people in disease-hit countries more access to treatment, diagnosis, better housing and better vaccines, she said. However, sweeping foreign aid cuts by Western countries have threatened progress against most mosquito-borne diseases over the last year, humanitarian organisations have warned.

Aedes aegypti mosquitoes infected with Wolbachia bacteria are released by a technician from the Federal District’s Health Department in a residential area of Brasilia.

A researcher examines Aedes aegypti mosquitoes kept in cages to collect their eggs.

Eggs of the Aedes aegypti mosquitoes. – ALL PICS FROM AFP

Flying bloodsuckers can learn to love common repellent, scientists find professor emeritus at the Insect Biology Research Institute at France’s University of Tours. insects tried to bite the fabric – even though there was no blood.

‘Paradigm shift’ For the experiment, the mosquitoes were put in a fabric mesh enclosure, then presented with a bag of warm sheep’s blood to observe how eagerly they fed on it. Unsurprisingly, the Aedes aegypti mosquitoes – which spread deadly diseases such as dengue fever, Zika, yellow fever and chikungunya – leapt at the chance. When the smell of DEET was introduced, the mosquitoes moved away, which was also expected. Next, the scientists fed the insects warm blood for 20 seconds, releasing DEET during the last 10 seconds. That part was repeated three times before the mosquitoes were exposed to solely the scent of the repellent. This time, more than 60% of the

MOSQUITOES can learn to associate the smell of the world’s most common insect repellent with a tasty meal – and after training can even prefer to bite people who have been sprayed with it, an experimental study said recently. The surprising results, which were conducted “under very specific conditions” in the lab, do not “call into question the effectiveness” of the repellent DEET, lead study author Claudio Lazzari told AFP. Since being developed in the 1940s in the United States, the chemical compound has saved many lives from the scourge of insect bites. “It is the absolute gold standard for repellents, used by the World Health Organisation to combat the transmission of mosquito-borne diseases,” emphasised Lazzari,

is toxic” to the mosquito, instead they are repelled by how they “interpret this chemical information”, Lazzari added. “What we are showing is the mosquito’s brain can rewrite that response based on experience. “What the insect has learned matters just as much as what the chemical does. That, I think, is a paradigm shift,” Vinauger explained. While the mosquitoes were trained relatively quickly during the experiment, in nature “very specific conditions would be needed for things to happen the same way,” Lazzari emphasised. He advised everyone to follow the instructions on their repellent because DEET can come in a variety of concentrations. The study was published in the Journal of Experimental Biology .

Then, one of the scientists offered up their hands – one clean, the other coated with DEET – to the trained mosquitoes to see which one they would bite. The result was beyond doubt: The insects preferred the hand covered in repellent. The scientists had similar results when they repeated the experiment using sugar instead of blood, because mosquitoes mostly feed on plant nectar in the wild. “The common assumption has always been repellents work because of their chemistry,” study co-author Clement Vinauger of Virginia Tech in the US said in a statement. But this study shows “it’s not the chemistry of the molecule itself that

However the world also needs to find new, more effective, environmentally friendly repellents that cause fewer allergies, he added. That means figuring out exactly why insects are so turned off by the repellents that we do have. “We don’t know why” compounds such as DEET deter mosquitoes, Lazzari admitted. Are they toxic for the little bloodsuckers? Do they stop mosquitoes from tracking down our scent? Or do they just smell bad? To find out more, the international team of scientists used a form of conditioning made famous by Pavlov’s dog, which learnt to associate the arrival of food with the sound of a ball.