Dengue is no longer a problem we can afford to treat as someone else's tropical disease. In 2024, the World Health Organization recorded more than 14.6 million reported dengue cases worldwide, the highest annual total ever recorded, along with more than 12,000 reported deaths. About half of the world's population is now considered at risk of dengue infection. In the Americas alone, more than 13 million cases were reported in 2024.
The numbers are alarming, but what concerns me most is that we are still approaching mosquito control too often from the wrong end of the problem. We focus on the adult mosquitoes flying around our neighborhoods because they are the ones we can see and kill. Meanwhile, the next generation is developing quietly in the places we overlook: a flowerpot, a clogged gutter, a discarded container, or something as small as a bottle cap. If we want to get serious about dengue prevention, we have to start where mosquitoes start.
Facing Up to New Challenges
Climate change is making that challenge harder. A Stanford-led study found that warming temperatures were responsible for an estimated 18 percent of dengue incidence across 21 countries in Asia and the Americas between 1995 and 2014. The researchers found that dengue transmission peaked at around 27.8°C and projected substantial increases in incidence by midcentury under future warming scenarios.
That means the geography of dengue is changing. Warmer conditions can make environments that were previously less suitable for Aedes mosquitoes increasingly hospitable. Urbanization adds another layer because cities give these mosquitoes something they need in abundance: people, buildings, and countless small containers capable of holding water.
The biology is remarkably simple. Aedes mosquitoes lay eggs in containers that hold water. The larvae and pupae develop in that water before emerging as adults. According to the Centers for Disease Control and Prevention (CDC), Aedes mosquitoes can develop from egg to adult in as little as seven to 10 days, and they can use everything from buckets and flowerpots to other small water-holding containers as breeding sites. The U.S. Environmental Protection Agency (EPA) goes even further, noting that some mosquitoes can breed in places as small as bottle caps.
That should change the way we think about prevention.
Thinking About Prevention
An adult mosquito is the final stage of a process. By the time we are spraying it, the mosquito has already survived the egg, larval, and pupal stages, emerged, found a host and begun moving through the environment. Killing that mosquito can be important, particularly during disease transmission, but it does not erase the breeding site that produced it.
This is not an argument against adult mosquito control. The EPA and CDC recommend integrated mosquito management precisely because no single intervention is sufficient. Adulticides can play an important role when disease transmission is occurring or when other controls are not feasible. But the same guidance emphasizes removing breeding habitat and controlling mosquitoes during their immature stages, when they are concentrated, immobile and accessible.
The problem is that some of the most important breeding sites are also some of the hardest for public authorities to reach.
A city can treat a public space. A mosquito-control district can conduct surveillance. A truck can move through a neighborhood applying an approved treatment. But what happens behind the fence of a private home? What happens in the backyard where a discarded container collects rainwater? What happens on a patio where a plant saucer remains wet for days?
That is where prevention has to become distributed.
This has led me to think more closely about how we can intervene earlier in the mosquito life cycle, before a new generation emerges and contributes to the spread of disease. The approach is based on attracting egg-laying female mosquitoes to a controlled environment rather than relying only on interventions directed at adult mosquitoes after they emerge.
The broader principle is what matters here. If mosquito populations can be addressed during reproduction, there is an opportunity to interrupt the life cycle before another generation becomes capable of flying, biting, and potentially transmitting disease. It is one additional way of thinking about prevention rather than waiting until adult mosquito populations have already increased.
We also need to recognize that repeated spraying is not an infinite solution.
Recent research from North Carolina State University found pyrethroid resistance-associated mutations in 84 percent of sampled residential blocks in Wake County by 2023, with 39 percent of sampled mosquitoes carrying the mutation. The researchers described the findings as an early warning, not evidence that pyrethroids have stopped working. But the development illustrates why mosquito management cannot depend on one tool indefinitely.
Time To Get Smarter With Chemicals
The answer is not to abandon chemical control. It is to become smarter about where, when and how we use it.
That means combining surveillance, source reduction, larval control, adult control, household participation and technologies that can remain active between professional interventions. It means recognizing that a mosquito control program cannot stop at the edge of the public road.
The backyard matters.
The patio matters.
The flowerpot matters.
And yes, the bottle cap matters.
For me, that is the larger lesson of the dengue challenge. We have spent decades becoming better at responding to outbreaks, but prevention requires us to think much earlier. The mosquito does not wait for a public-health department to declare an outbreak. It finds a container, lays its eggs, and begins the next generation.
Our prevention strategy needs to work on that timeline too.
We have to accept that public health cannot physically reach every backyard.
That does not mean those spaces have to remain outside the prevention system.
It means prevention has to be designed to reach them through tools, education, and participation that put mosquito control closer to the source.
If dengue is changing with our climate and our cities, our mosquito-control strategies have to change with it. We cannot keep waiting until mosquitoes are flying, biting and transmitting disease before we act.
Enrico Levi is the founder and CEO of INZECTO, a pest-management company that develops and sells mosquito-control products. All views expressed are the author’s own.