These mosquitoes are created by injecting mosquito eggs in the lab with a killer gene. It produces a protein called tTA, which stops the mosquitoes' cells from turning on other genes which are essential for the bugs to survive.
The resulting GM male mosquitoes are then released into the wild to breed with non-GM females, producing offspring genetically programmed to die well before reproductive age.
The company says that as the number of GM males introduced into an environment increases, the lower the chances the non-GM males have of breeding with non-GM females, until eventually the mosquito population can be effectively eliminated.
Oxitec says it has done tests in Brazil, Malaysia and the Cayman Islands, which show mosquito numbers can be greatly reduced in a few months.
"You first release a few thousand males to see if they will mate, then you move to a control programme. In the Cayman Islands we released 3 million over a few months over 16 hectares. We effectively brought the overall mosquito population down by 80% in three months," Oxitec's CEO Haydn Parry told BBC World Service.
While only GM males are intentionally released, critics point out and Oxitec acknowledges that the release of a small number of GM females cannot be avoided. The males are filtered out for release from the generally bigger females, but some females slip through the net. It is only the female mosquitoes which bite and spread disease.
However, Mr Parry says the small number of GM females that do get released present no danger even if they bite humans. "It's exactly the same as being bitten by a wild one," he says. "The gene, or protein, that prevents the next generation from surviving isn't toxic or allergenic and isn't expressed by the saliva glands" and therefore is not injected into humans when they are bitten.
.
