Oxitec’s GMO mosquitoes have already been tried and failed in three countries. Malaysia stopped their trial and killed all the released mosquitoes, finding it ineffective in combating Dengue. Brazil stopped a trial after realizing that tetracycline available in the environment allowed the GMO mosquitoes to reproduce by switching-off the lethality gene. Panama killed the budget for their GMO mosquito test after concerns arose about the program’s effectiveness.
Kuala Lumpur, site of the Malaysian trials, decided after four years of studies that the GMO mosquitoes had no lasting impact on the target species. All three countries pointed out the impracticality of scaling the Oxitec method of breeding, shipping, hatching, sex sorting, and releasing as it requires huge amounts of mosquitoes and personnel and incurs high costs that all these countries found inappropriate.