- by Alison

Oxitec field trial: Brazil tests crash mosquito population by up to 96%

In the first of our two-part series looking at Oxitec’s 2nd generation Friendly™ Mosquito technology, Grey Frandsen, Oxitec’s CEO, explained their self-limiting mosquitoes potential to fight dengue. In this second part, Frandsen shares news on developments in Brazil, explains why public engagement is so important and reveals two new strains of their mosquito technology designed to stop the spread of vector-borne diseases.

Oxitec has been working in Brazil with its 1st generation Friendly Aedes aegypti technology for some time. Aedes aegypti is the main vector for dengue fever – reducing the mosquito population could play a vital role in curbing global dengue outbreaks. “Over the past eight years, we have achieved great Aedes aegypti control across multiple cities, project sizes and project types,” says Frandsen. “Our four-year partnership with the Brazilian city of Piracicaba has shown sustained performance over time, achieving significant suppression year-after-year.”

Brazil trials

New study raises questions

Researchers at Yale University have published a study in Nature: Scientific Reports showing that genes from genetically-modified mosquitoes have been passed on to subsequent generations.
The scientists examined mosquitoes in the Bahia region where Oxitec had released almost 450,000 male mosquitoes in the city of Jacobina over a 27-week period. The mosquitoes are designed in a way that should ensure their offspring cannot reach adult stage.

This should have meant that the GM-mosquitoes could not reproduce. However, the study found that the Oxitec mosquitoes’ genes were present in the population, leading critics to claim that the experiment had failed.

The biotech company has selected Indaiatuba, a municipality in the state of São Paulo, for the first field trial of its 2nd generation technology, a pilot project aimed at demonstrating the new strain’s effectiveness in suppressing populations of the Aedes aegypti mosquito. In partnership with the city’s municipal vector control authorities and under approval issued by Brazil’s national biosafety authority, CTNBio, Oxitec released Friendly Aedes aegypti in a year-long trial starting in May 2018.

The results for the first field trial, which covers four separate densely populated urban communities across the city, are now in. “The pilot was a success,” says Frandsen. “Relative to the untreated control area, releases of Friendly male mosquitoes achieved an average of 89% peak suppression across the two communities treated with a low release rate of mosquitoes and an average of 93% across the two communities treated with a higher release rate. At peak, one of the communities with a high release rate achieved a 96% suppression across four weeks.”

Plans are afoot for further field trials in Brazil in 2019 and 2020. These trials will more broadly evaluate the performance of the 2nd generation strain, including its deployment as eggs and the strain’s potential as an insecticide resistance management tool.

Public engagement crucial to success

“Engaging stakeholders collaboratively and transparently is a large part of successfully ushering a new technology to market, which is precisely what we’ve tried to do in every country and with every partner,” says Frandsen. Oxitec is continuing with its previous public engagement approach for its new technology. Frandsen explains: “We treat public engagement as an integrated element of our technology, not just a prerequisite for deployments in a given locale. We take a dedicated and thoughtful approach to education and information sharing, and we always rely on transparency, openness and direct dialogue with our key stakeholders.”

In every area that Oxitec works, it does so in partnership with governments and communities. “We’ve had exceptionally high levels of support at local, national and international levels,” says Frandsen. “And with more than 100 Oxitec-authored peer-reviewed publications, communication of our technology to the public is founded on strong science. Any stakeholder can evaluate our technology, our projects and our results at any time.”

Expanding to the fight against malaria

Alongside progress on its 2nd generation Aedes aegypti strains, Oxitec has partnered with the Bill & Melinda Gates Foundation to develop new Friendly Mosquito strains to combat two malaria-carrying mosquitoes:

  • Anopheles albimanus, one of the most important vectors of malaria in Central America, and
  • Anopheles stephensi, a malaria vector in Asia and the Middle East that has, in recent years, invaded the Horn of Africa, presenting a growing public health threat to the African continent.

The new ‘Friendly Anopheles’ strains will also incorporate Oxitec’s 2nd generation technology.

Endorsements and approvals around the globe


At a global level, the World Health Organization has endorsed Oxitec’s technology, joining a long list of national and regional regulatory bodies and organisations:

  • a positive recommendation from the World Health Organization’s Vector Control Advisory Group for use in pilot efforts against Zika during the global Zika crisis;
  • Findings of No Significant Impact from the US Food and Drug Administration and US Department of Agriculture;
  • approvals for release into the environment in the Cayman Islands, Panama and Malaysia;
  • positive technical opinions from regulatory agencies in the Netherlands and France; and
  • approvals for contained studies in the UK, India, Morocco and Australia.

New mosquito control tools are sorely needed to support vector management efforts around the world. “We broke the mould with the first release of genetically engineered mosquitoes in 2010, and we’re proud to advance once again the next generation of self-limiting insect technology designed to solve for the precise challenges of cost, safety, targeted suppression, and insecticide resistance,” concludes Frandsen.