A $588,000 project to test the effectiveness of genetically modified mosquitoes in combination with traditional control methods will begin later this month.
Government and its Mosquito Research and Control Unit walked back on plans for an $8 million national rollout of the technology amid skepticism from its scientists about results claimed by partner company Oxitec in a trial deployment last year.
They have not given up on the technology completely, however, and preliminary work on a new project is already under way in West Bay.
Dr. Jim McNelly, who took over as head of government’s mosquito unit in March, said this was not simply a “reboot” of last year’s work.
He said GM mosquitoes would be assessed alongside other methods, including spraying insecticides from a plane, in an integrated mosquito management approach.
“I would say this is probably the final evaluation of this and it will help us to decide whether utilizing GM mosquitoes going forward is a viable option for inclusion within our tool kit,” he said.
Representatives from Oxitec, the Mosquito Research and Control Unit and the Ministry of Health presented a united front in an interview with the Cayman Compass Friday, as they defended the continued use of the technology in the Cayman Islands.
A series of internal emails, released under the Freedom of Information law and reported in the Compass last week, revealed that scientists within government’s mosquito unit were consistently questioning success rates claimed by Oxitec during last year’s project.
Despite the well-publicized reservations of his team over Oxitec’s methodology for measuring success rates, Dr. McNelly said there was strong evidence that the technique did work. However, he said GM mosquitoes should not be considered a “silver bullet” and any future deployment would be as part of a combined approach.
“It has potential as a tool among many tools that could be combined to achieve the eradication of the Aedes aegypti mosquitoes from Grand Cayman,” he said.
Dr. Renaud Lacroix, Oxitec’s representative in the Cayman Islands, defended the company’s claim of a 62-percent suppression rate – reported in the unit’s annual report but disputed by scientists in the MRCU internally – as a “robust analysis.” He put the disagreement over this figure down to differences in opinion over how the number should be calculated.
“Whatever is in the report had been agreed and reviewed. If the MRCU wants to re-analyze the data in another way, then that is their right,” he said. Dr. McNelly said the two entities were now on the “same page” over how the data from the new project should be analyzed.
He said a representative from the Caribbean Public Health Agency had now been appointed to the steering committee for the project to provide further independent analysis of the results.
The new trial will test three different areas in West Bay. In one area, traditional methods will be used alone. In a second area, these same methods will be used in combination with low-level releases of genetically modified mosquitoes and in a third area, they will be used in combination with releases of much higher numbers of genetically modified mosquitoes.
Dr. McNelly added, “At the end, we will sit at the table as scientists and managers and discuss the results and determine whether we feel as though suppression rates were positive and then managers make decisions on whether this product will be included in our program.”
He said the unit would also investigate other methods as well as GM mosquitoes, citing a technique involving Wolbachia bacteria as another option.
“There are other promising non-insecticide techniques. If we can reduce our reliance on short-term solutions like insecticides, then that is a brilliant way to go,” he added.
Addressing the controversy over a report, submitted to the National Conservation Council as part of the permit approval process for the last project, the representatives of government, the MRCU and Oxitec acknowledged that the private company was the principal author of that document.
Nancy Barnard, the deputy chief officer in the Ministry of Health, who led the MRCU on an interim basis in the latter part of last year, provided emails and minutes from a steering committee meeting, which demonstrate that MRCU staff viewed, and in some cases amended and approved the report before it was filed. Dr. Lacroix acknowledged that he was the principal author but said MRCU staff, including those who later raised concerns about the content, were given a week to review it and made substantial additions.
The report, filed with the council, does not indicate any involvement on the part of Oxitec in its preparation, and appears on government letter head.
Dr. McNelly said it was not uncommon for “vendors,” who have access to the data and relevant information, to provide reports associated with particular projects. But he said going forward MRCU would take greater ownership of any report coming out of this partnership.
“In a perfect world, the MRCU would have been more responsible for providing that report. The vendor would have certainly provided the data and the initial analysis on the data. Moving forward, I would expect when we are required to provide a report, the MRCU will take the lead on what ultimately will be a collaborative report.”