Part II: On a Mission to Stop the Mosquito
In Part I of this interview, Dr Nimmo discussed his role at Oxitec, and described how Oxitec’s proposed trial of its self-limiting mosquitoes in Florida would run. Here, he explains the regulatory process for the trial, and discusses his work interacting with the local community and answering their questions about the technology.
Q: How did Oxitec get its start in Florida?
DN: Back in 2009, when Key West was having a dengue outbreak, I went to an American Mosquito Control Association meeting. I met Ed Fussell, who was the director of the Florida Keys Mosquito Control District at that time. He invited us down to Florida and told us that nothing they were doing seemed to be working. Through a lot of hard work and money – and because the mosquito population is seasonal – they managed to control the dengue outbreak. However, they realized that new tools were desperately required.
Q: What’s happened since then?
DN: We’ve been working through the regulatory process to trial our engineered mosquitoes in the Florida Keys. We started out by submitting an application to the U.S. Department of Agriculture (USDA) Department of Veterinary Services. This included an environmental assessment of the proposed trial.
USDA had previously evaluated our technology in an agriculture context and given us permission in 2007 to release our engineered pink bollworm in Arizona. That’s an important point to note: we have actually released engineered insects in the U.S. before.
After about a year, the USDA came back with a letter of no jurisdiction, which meant that they felt they weren’t the right agency to regulate mosquitoes as they couldn’t identify any risks to animal health. The Food and Drug Administration Center for Veterinary Medicine (FDA-CVM) then contacted us to say they would be regulating the mosquitoes as an Animal Drug under the Food and Drug Cosmetic Act.
FDA-CVM pulled in additional expertise from the Centers for Disease Control and Prevention (CDC) and the U.S. Environmental Protection Agency (EPA) to review the application we had to make for the Key Haven trial.
For the past four years, we’ve been providing information, protocols and procedures for the FDA-led review, which included preparing a draft environmental assessment. We also built a 350-square foot facility in Florida, which passed inspection by the CDC and the FDA in 2015.
In March 2016, the draft environmental assessment and a preliminary finding of no significant impact were published in the Federal Register. That triggered a 60-day comment period, which finished in May. Then, after extensive review of our dossier and thousands of public comments, in August the FDA-CVM released a final environmental assessment and a final finding of no significant impact.
Q: What exactly does it mean to receive a finding of no significant impact?
DN: The FDA’s committee consisted of members from the FDA, CDC, and EPA. All of them have reviewed the environmental assessment and public comments, and concluded that the trial in Florida would have no significant negative impact on human health, animal health or the environment.
Q: There is now going to be a referendum on using this technology – can you clarify what this involves?
DN: On November 8, Keys residents will vote on whether they want to see the use of genetically engineered mosquitoes to control Aedes aegypti in Key Haven and elsewhere in Monroe County. This is a nonbinding referendum, and after the vote the board will make the ultimate decision about whether the trial will go ahead.
Q: What would the trial look like if you do get approval?
DN: The trial itself would be fairly small scale. It is proposed to take place on an island called Key Haven near Key West, which covers about 440 houses. We would treat one-third of that island with our Oxitec mosquitoes. We’d release them into that area; they’d mate with local females and pass on the self-limiting gene, which causes the offspring to die. We’d also have a control zone, where we wouldn’t release anything, and a buffer zone between the two zones. On average, Aedes aegypti fly around 200 meters in their lifetime, so it’s possible to separate the sites. We’d then compare results in the control zone to those in the release zone. Any other currently employed mosquito control methods would continue alongside our trial in all the zones.
We expect to see similar suppression results as we observed in Brazil, the Cayman Islands, and Panama, where we achieved control over the Aedes aegypti population in about six to nine months. If we see those results again in Florida, we would send our findings back to the FDA, and this would feed into the process of regulatory review. If approved by the FDA, this would then potentially allow us to use the technology anywhere in the U.S. to fight this dangerous mosquito.
Q: You’ve been actively engaged in establishing the Florida trial, including setting up the facility in Marathon. What has your experience been like on the ground?
DN: For over five years, I’ve been doing town hall meetings, meeting with Key Haven residents, knocking on doors, giving radio interviews, and talking to commissioners and local politicians – so there has been a lot of community engagement down in the Keys.
Generally, when I talk to the public, people say, “Okay, I can see this working, get the regulatory approval and do it.” The Florida Keys Mosquito Control District has done five different surveys, a couple of them with independent universities, and those surveys have shown that a majority of people are in favor of using this technology.
However, there’s a vocal minority of people who are against the project and a couple of groups who are fundamentally opposed to genetic engineering of anything. They are concerned that if we get permission to use our mosquitoes, it will pave the way for lots of other genetically engineered organisms.
I have been talking to these people and explaining the benefits of our technology, as well as showing them the really positive results we’ve had in suppressing Aedes aegypti overseas. Some people hear “trial” and imagine that this is a new or untested technology – so it’s important to highlight that our mosquitoes are actually being used operationally elsewhere in the world. It’s not just the FDA, CDC and EPA that have assessed this technology – every country that has conducted trials has done so following regulatory assessment, and in Brazil we have had permission from biosafety regulators to release the mosquitoes anywhere in the country. In response to the Zika epidemic, this year the World Health Organization recommended pilot deployment of our mosquitoes under operational conditions. In Brazil and the Cayman Islands, we have moved to programmatic roll-out of the technology.
Q: What are some of the key things you would like people to understand about the potential Key Haven trial?
DN: This is well tried technology. We have investigated this product for over 10 years and we have conducted successful releases since 2009 in Cayman, Brazil and Panama, which have been approved by regulators. We’ve accumulated a significant amount of data, much of which has been published in numerous peer-reviewed journals, and have had no reports of any adverse effects on humans or the environment. The only effect we have seen is over 90% control of this mosquito that transmits Zika, chikungunya, dengue and other dangerous viruses to humans, which is a far greater level of control than any current method.
Q: What is happening now in the places you have done trials?
DN: We are now deploying our mosquitoes in two of the places we completed trials, Brazil and the Cayman Islands.
With respect to Brazil, we received permission from biosafety regulators in 2014 to release our mosquitoes anywhere in Brazil. Our first programmatic deployment started in Piracicaba in 2015 to treat an area of approximately 5,000 people. After one year they expanded that contract to treat an area where 60,000 people live, and we’re now building a larger factory in Brazil. In July, Piracicaba’s Epidemiologic Surveillance service released data showing that the rate of dengue in the CECAP/Eldorado district in which we were releasing our mosquitoes had decreased by 91% from the previous year, compared to a 52% reduction in the rest of the city.
Moving on the Cayman Islands, in July we began releasing our mosquitoes in an area of 1,800 people in Grand Cayman, in collaboration with the Mosquito Research and Control Unit there. We ultimately hope to rollout our technology over the rest of the island to suppress the population of this mosquito that transmits Zika, dengue, chikungunya, and other diseases.