(CNS): The release of hundreds of thousands of genetically modified male mosquitoes is beginning to make its mark on the population of the Aedes aegypti species in the district of West Bay, officials managing the project said after the genetic markers began showing up in insect larvae. Dr Renaud Lacroix, the manager of the Oxitec project, said that around 400,000 bio-engineered bugs are now being released each week and those males are breeding with the existing female population. Since the release began six weeks ago, around 10% of the larvae examined by the researchers show the fluorescent genetic marker associated with the GM mosquito.
The Mosquito Research and Control Unit (MRCU) is engaging in a full-scale war against the mosquito as a result of the emergence over the last few weeks of several locally transmitted cases of Zika. But the unit is coordinating its daytime insecticide spraying of the adult Aedes aegypti with the Oxitec release days.
This is to avoid killing the genetically altered bugs to give them a chance to compete with the natural males and breed with females. The female only reproduces once in a lifetime, so if a GM male gets to be her one and only, the larvae she produces will not reach adulthood, ensuring the gradual demise of the disease-spreading, invasive species.
Lacroix said that with the recording of the GM larvae and the increase in the release numbers, it is expected that the percentage of larvae born to GM fathers will increase more rapidly, and the scientists expect to see a dramatic fall in the numbers shortly afterwards.
The 300-acre release site in West Bay is next to a comparative site of the same size where no GM bugs have been released to help give the project a yardstick. But with mounting concerns regarding the spread of Zika virus by the mosquitoes, both areas are still being sprayed with insecticide and larvaesides to protect the resident population.
So far there have been no reported cases of Zika transmission in West Bay and the project cannot be transferred to the capital, experts have confirmed.
Speaking at a press briefing on Tuesday, Lacroix explained that the Oxitec project is being tightly regulated and they only have authorisation from the National Conservation Council to release a certain amount of bugs in a very specified area over a given time period. Before they could begin a parallel project in the capital they would need to go through a long bureaucratic process, which could take many months.
Although Lacroix stated that there are plans for an island-wide rollout, in which George Town would be the next phase, that is at least nine months away. However, he said that taking the project to George Town would not have an immediate impact on the current issues because it is a long-term tool for the future eradication of the insect and not suited to immediate mitigation when there is a real and present disease threat.
While the GM solution is not the answer for an immediate reaction to the spread of Zika, which is happening now, the arrival of the virus in Cayman has “complicated things”, according to MRCU Director Dr Bill Petrie.
The MRCU may give consideration to a faster operation roll out of the island-wide GM project but that would depend on the findings over the coming weeks from the West Bay releases.