http://www.sciencemag.org/news/2019/11/mosquitoes-armed-bacteria-beat-back-dengue-virus > A World Mosquito Program staff member releases Wolbachia mosquitoes in Brazil. > NATIONAL HARBOR, MARYLAND—In a handful of cities around the world, mosquitoes have been armed with a microscopic weapon against disease. The bacterium Wolbachia pipientis blocks the insects’ ability to spread fearsome viruses such as dengue, Zika, and chikungunya. Since 2011, researchers have been injecting Wolbachia into the eggs of Aedes aegypti mosquitoes and releasing the hatched insects, which spread this protection to their offspring. But the field has been waiting for evidence that this approach actually reduces disease in people.