Scientists Turn Mosquitoes Into Tiny Weapons to Fight Disease

On a warm tropical morning, a group of residents gathered in Singapore to examine canisters humming with male mosquitoes. A few people reached in, boldly testing the promise that the insects, infected with a bacteria that stops them from reproducing, don’t bite.

The mosquitoes are part of Singapore’s $1.45 million four-year effort to bring down record levels of dengue, which it estimates has cost the government up to $2.2 billion in the decade through 2020 to fight.

The wealthy city-state is at the forefront of both a global surge in mosquito-spread diseases, and efforts to weaponize the insects against the ...