- by Alison

Oxitec’s new Friendly mosquitoes: could they unlock new possibilities in the fight against dengue?

In the 18 months since we last met with Oxitec, the ‘Friendly™ Mosquito’ biotech company has a new CEO and has been busy advancing new technologies, new partnerships and new initiatives. By releasing self-limiting mosquitoes, they are able to control populations of the Aedes aegypti, the main vector of dengue fever and other diseases. The company has recently announced that the total number of Friendly Aedes aegypti released globally has passed the 1 billion mark. We spoke with Grey Frandsen, Oxitec’s CEO, and his staff. In this first of our two-part series, Frandsen reveals Oxitec’s 2nd generation Friendly mosquito technology.


“This has been an incredibly exciting period for the team at Oxitec. Over the last 18 months, we’ve launched our new 2nd generation technology platform for mosquitoes, entered into new partnerships in both the public health and agricultural spaces, and expanded our technology into the fight against malaria,” says Frandsen.


Oxitec has recently announced a new partnership with the Bill & Melinda Gates Foundation to develop new malaria-focused Friendly mosquito technology and the expansion of its agricultural program with two new crop pest initiatives.


Self-limiting insect technology


A UK company and wholly owned subsidiary of Intrexon, Oxitec Ltd was founded in 2002 as a spinout from the University of Oxford. The company positions itself as a pioneer in utilising genetics to develop solutions to insect pests that spread disease and damage crops. Oxitec’s mission is to “save lives and improve livelihoods by developing safe, highly-effective biologically-engineered solutions to control disease-transmitting and crop-destroying insects globally.”


Oxitec has developed a novel solution to control harmful insect populations, including the Aedes aegypti mosquito species that spreads dengue fever, Zika, chikungunya and yellow fever. This ‘self-limiting’ platform utilises proprietary and precision genetics to embed self-limiting properties in mosquitoes, agricultural pests and other insects.


Oxitec’s transition to its 2nd generation technology represents the next phase of its mission to target Aedes aegypti. “Our most recent announcements include the complete transition to our new 2nd generation platform and successful field trial results of our 2nd generation Aedes aegypti technology,” says Frandsen. “We’ve been busy!”


So, how does Oxitec’s 2nd generation Friendly mosquito technology work?


The Friendly mosquitoes technology


Oxitec’s 1st generation approach involved releasing genetically engineered male mosquitoes that, like their male counterparts in the wild, do not bite or transmit disease. After the adult males mate with wild female mosquitoes of the same species, their offspring die before reaching maturity.


“Following sequential releases in several countries over the last decade, we have shown that Aedes aegypti can be reduced by more than 90% in urban environments using our 1st generation genetically engineered strain,” says Frandsen.


Oxitec has now transitioned to a new strain of self-limiting Aedes aegypti mosquito that uses its 2nd generation ‘Friendly’ technology. The 2nd generation males mate with wild females after being released into the wild. However, only female offspring die before reaching adulthood, providing what Frandsen describes as “near-term suppression effects”.


Multi-generational but self-limiting suppression effects


The male offspring inherit the self-limiting gene and can survive to adulthood. They seek out and mate with wild females, eliminating the next generation of females while passing the self-limiting trait to the next generation of males. This is different from the 1st generation technology, which could not provide suppression effects over multiple generations from a single release as both male and female offspring died.


“As the self-limiting gene is passed on through males, its occurrence gradually declines in each successive generation, ultimately to disappear eventually,” says Frandsen. “In the meantime, it also prevents any female carriers of the gene from surviving to reproduce. These major technical advancements unlock a range of performance and operational benefits.”


Oxitec anticipates a potentially greater impact per released insect with its 2nd generation insect. Designed to provide a multi-generational but self-limiting suppression effect, it expects improvements in pest suppression and cost-effectiveness.


Reversing insecticide resistance


The new technology has other benefits too: it also introduces the potential for countering the growing spread of insecticide resistance in target insect pest populations.


“Our 2nd generation technology will be ideal for use within integrated pest management programs because it has the potential to reverse the resistance that mosquitoes are developing to traditional pesticides,” says Frandsen. “So, this means that end-users may be able to simultaneously extend the life of existing chemical control tools while reducing the amount of insecticides necessary for effective suppression.”


Unlocking operational benefits


Frandsen also highlighted other new benefits: “Our new 2nd generation technology has the potential to be a highly scalable intervention tool that is more easily deployable by non-specialist staff without large rearing facilities or equipment. Our continued investment in new deployment modes for our new 2nd generation Aedes aegypti mosquito will provide alternatives to costly adult mosquito rearing facilities that other technologies must use.”


The technology, Frandsen tells us, also solves one of the most significant cost-drivers and operationally challenging requirements for insect release technologies: “By preventing females surviving, our technology eliminates the possibility of releasing the female insects (which bite and transmit disease), and therefore also the need for sex-sorting in the manufacturing process.”


Oxitec is now accelerating product development for scalable commercial solutions for use by anyone. These “big advancements expand what is possible within our broader public health and vector control community,” says Frandsen.


“We’re looking forward to a busy year as we ready our 2nd generation technology for large-scale deployments,” he continues. “Once fully developed, we believe this will be the first technology capable of giving governments and commercial end-users the power to deliver safe, effective Aedes aegypti control with an easy-to-deploy, cost-effective and still self-limiting solution.”


In the second of our two-part series, Frandsen shares news on developments in Brazil, explains why public engagement is so important and reveals two new strains of Oxitec’s 2nd generation Friendly mosquitoes technology.