Oxitec has developed the Friendly™ Aedes solution, genetically engineered male mosquitoes used in Brazil today to combat the spread of Aedes aegypti. Wild female Aedes aegypti carry and transmit mosquito-borne diseases including Zika, dengue and chikungunya. Oxitec’s Friendly™ male mosquitoes, which do not bite, mate with wild females and pass on a gene that prevents their offspring from reaching adulthood.
Oxitec and Piracicaba City Hall initiated the Friendly™ Aedes project in 2015 in an area of 5,000 people in the Eldorado/CECAP district. The project was expanded in 2016 and Oxitec’s solution is now being used to cover an additional area of 60,000 residents in downtown Piracicaba.
We spoke with Guilherme Trivellato, Oxitec’s project manager for Piracicaba, to get an update on the project. Trivellato, an agronomist with a master’s degree from the University of São Paulo and an expert on biological pest control, has worked for Oxitec since the company began operating in Brazil in 2013.
Q: We’ll get into the Piracicaba project in a moment, but first we wanted to know what led you into this field.
Guilherme Trivellato: Both of my parents are biologists. Since I was a kid, we used to go to the countryside and they taught me how to look at the natural world through biology. Later, I went to the University of São Paulo to get an undergraduate degree in agronomic engineering. My advisor made me realize how harmful chemical pesticides can be for people and the environment and that they also don’t work so well. So in my second year I got interested in biological controls of pests. Moving that interest forward, I received my master’s degree from the University in entomology, focusing on how we can use parasitic wasps and ladybugs for pest control. After I graduated, Oxitec invited me to become part of the project they were setting up here in Brazil.
Q: Tell us more about the Friendly™ Aedes Project that has been taking place in Piracicaba since March 2015.
GT: The groundwork was actually laid for the Piracicaba project a few years before. In 2011, the first Friendly™ Aedes trials started in Brazil. After the trials, the National Biosafety Technical Commission (CTNBio) issued an approval, stating that the Friendly™ Aedes does not pose any risk to the environment, people and animals. In July 2014, we opened a production facility in Campinas that can produce 2 million engineered male mosquitoes per week. We release males because they don’t bite and cannot transmit viruses like dengue, Zika, chikungunya, and others. All they do is look for females to mate with, and they do it very efficiently.
In March 2015, we signed a contract with the city of Piracicaba to release our mosquitoes in a small neighborhood of 5,000 residents called CECAP/Eldorado. We started treating the area with Friendly™ Aedes in April 2015. We monitored our mosquito with traps in the treatment area weekly, and after six months we were able to see a strong impact on the population of wild Aedes aegypti. By December, we recorded a decrease in wild Aedes aegypti larvae of 82% compared to an untreated control site. In July 2016, Piracicaba’s Epidemiological Surveillance service reported a 91% decrease in dengue cases at CECAP/Eldorado while in the rest of the city the decline was 52%.
Q: How do you actually release the mosquitoes into the neighborhood?
GT: At our breeding facility, we load pots with up to a thousand male mosquitoes each and put those pots into a van. We can get up to 800,000 insects into the van per trip and then go through a neighborhood three to five times a week. We have predefined release points and blow the males out of the van using an adapted fan. We actively monitor Aedes aegypti using mosquito egg traps in the neighborhood between releases and adjust how many mosquitoes we send out based on how effectively the treatment is already working.
Q: In your opinion, why are Oxitec’s genetically engineered mosquitoes more effective than traditional methods?
GT: With control tools like pesticides, it is hard to reach all areas where mosquitoes breed and lay eggs. So you have to spray as much as you can, leaving these chemicals everywhere and often not reaching all the breeding spots. Yet, with our species-specific biological control method, the engineered male mosquitoes go out and actively search for the wild Aedes aegypti females. After mating with wild females, our mosquitoes pass on a gene to the offspring causing them to die before reaching adult stage. This process drives down the wild mosquito population over time with repeated releases of the engineered males. Compared to pesticides, Oxitec’s Friendly™ Aedes is much more environmentally friendly, since it is toxin free, it does not persist in the environment, and is targeted for Aedes aegypti without affecting beneficial insects.
Q: What’s next after the success you saw in CECAP/Eldorado?
GT: In May 2016, Oxitec signed a contract to apply our Friendly™ Aedes solution to ten additional neighborhoods in the central area of the city where people go during the day for work and shopping. The idea is that the benefit delivered will be much broader than only local residents, as people commute between the city center and surrounding neighborhoods, which may contribute to the spread of infestations and infections. While the area covering more than 4.6 square miles is home to roughly 60,000 residents, more than 100,000 people pass through that area in a day.
Additionally, in late October, we opened a first-of-its-kind mosquito production facility 10 minutes from downtown Piracicaba. It’s a 5,000 square-meter building that can produce around 60 million mosquitoes every week, enough to protect up to 3 million people. The new facility demonstrates how we can produce Friendly™ Aedes at scale.
Q: Besides decreasing the Aedes aegypti numbers in Piracicaba, what are you hoping to get out of this project?
GT: We already know that our mosquitoes work and expect to see the same successful reductions of Aedes aegypti in the expanded coverage area. Now with more time, a larger area and more resources, we’re working to further improve the efficiency of our processes. We’re improving several aspects of production, release and monitoring. Now we are able to undertake projects at greater scale.
Q: What do the locals have to say about this repeated release of genetically engineered mosquitoes in their streets?
GT: The people around here in Brazil have suffered greatly from dengue, chikungunya and Zika. Everyone knows someone who has had one of these diseases or who died from it. And here basically everyone supports the Friendly™ Aedes project in Piracicaba. In a survey conducted by the Research Institute CW7 in November 2016, 92.8% of Piracicaba’s residents supported the Friendly™ Aedes Project. In CECAP/Eldorado this number is almost 100%.