When interviewing a CEO, you don’t normally expect them to say that their greatest aspiration is to “go out of business.” And yet that’s exactly what Scott O’Neill told me when I interviewed him earlier this year about his non-profit, the World Mosquito Program (WMP).
For O’Neill, who founded WMP, going out of business means eliminating many of the world’s mosquito-borne illnesses, like dengue, yellow fever, chikungunya, and Zika virus. It’s a lofty goal — today over 1 million people die annually from these diseases — but the World Mosquito Program may have the key to reaching it.
“I’ve been working on this my whole career,” said O’Neill. “I have been particularly interested in an approach that’s practical for developing countries that don’t have a lot of money to think about a public health solution for these diseases.”
But what sets the program apart from other anti-dengue initiatives is that O’Neill isn’t focused on traditional prevention or treatment methods like vaccines or drugs. Nor is he trying to directly kill mosquitoes through insecticides. Rather, WMP actually mates mosquitos.
Wolbachia is a harmless, naturally occurring bacteria in many insects. When the Aedes mosquito (the species that carries many deadly viruses) is infected with Wolbachia, the bacterium competes with viruses, like dengue and Zika. Because it’s believed Wolbachia induces an antiviral response in mosquitos, it prevents the insects from becoming carriers of diseases when they bite an infected person.
The program breeds Aedes mosquitos for Wolbachia and then introduces them into the natural environment, which transforms the natural population of mosquitos into Wolbachia carriers. Once the Wolbachia-positive mosquitos are self-sustaining in the wild, then rates of dengue, yellow fever, Zika, and more decrease.
“It’s exactly the same rationale for how vaccination works for humans. So you don’t need to vaccinate 100 percent of the people in the population to give protection to the whole population,” O’Neill told Vox.
Notably, Wolbachia treatment can’t prevent malaria — as that disease stems from a parasite, not a virus, and is carried by a different mosquito. But there is hope that as research mounts the treatment could be used to combat malaria in the future.
WMP launched in Australia in 2011 to combat dengue in the area and, since then, the Cairns region in the country has reported no local dengue outbreaks. In the decade since, WMP expanded its work to 13 countries, including Mexico, Laos, and Fiji. And earlier this year, WMP announced that it is preparing to open its largest “mosquito factory” in Brazil in 2024 to combat dengue in the country, which had the second-highest rate of cases in the world last year.
New vaccines against dengue fever have shown increasing promise in recent years, but they’re not foolproof. The plethora of ways the viruses work through the immune system complicates how mosquito-borne illnesses can be treated. To make matters worse, the increasing scope of mosquitos’ territory also factors into the prevalence of these diseases. Infectious disease experts fear that even with more effective vaccines, we won’t be able to distribute them fast enough to keep up with evolving diseases — and growing mosquito populations.
If greenhouse gas emissions (and the resulting climate change) continue at current levels, 49 percent of the world will live in areas with Aedes mosquitos by 2050, a 2019 study published in Nature Microbiology found. Urban areas previously outside the Aedes mosquito scope, such as those in the southern United States and Europe, will battle these pests in the decades to come.
O’Neill views WMP’s approach as a cost-effective and socially acceptable alternative to practices like genetic modification, where unnatural bacteria or other changes are made to the mosquitos.
WMP estimates their approach costs $2 to $3 per person to implement while outside estimates place the cost at $15 per person. For an urban area of 50,000 people, this would mean WMP’s approach costs anywhere from $100,000 to $750,000 in its initial implementation. In contrast, implementing a genetic modification program — where mosquitos are essentially implanted with an artificial kill switch that prevents them from reaching reproductive age — in a city of 50,000 would cost approximately $1.9 million in the first year.
In 2021, when the biotech firm Oxitec planned on releasing these genetically modified mosquitos into the Florida Keys, the project was criticized by locals for its potential to cause unforeseen health or ecological repercussions, with over 200,000 people signing a petition against the release (despite this pushback the program did move forward as planned). Genetic modification could result in new breeds of mosquito emerging, alter the infectiousness of carried illnesses, or even change how the mosquito carries such viruses.
WMP’s approach faces a different set of challenges. The process takes longer, and lab-raised mosquitos don’t always thrive as well in the wild compared to their naturally reared counterparts. The viruses that this treatment defends against will also continue to evolve in an attempt to outmaneuver Wolbachia.
Still, WMP’s work is one of the most promising tools the world has to fight mosquito-borne diseases.
“It’s a challenging prospect for people to understand,” O’Neill told CBC. “But when people live in transmission areas and are fearful of the disease and the impacts it can have on families, people are desperate and hungry for new approaches.”