I assume that mutating. We release 1bn sterile mosquitoes, most die, but 1,000 of them have a random mutation on top of the original mutation and become hermap

I assume that mutating. We release 1bn sterile mosquitoes, most die, but 1,000 of them have a random mutation on top of the original mutation and become hermaphrodites. Now they reproduce on their own and become invincible microbots that bring zika to the masses. Of course that could also happen in the wild with some good 'ol cosmic rays and no human intervention.