Dengue fever infections dropped dramatically in an Indonesian study where a bacteria was introduced into disease-carrying mosquitoes, offering hope in the battle against an illness that sickens millions annually around the world.

The study was conducted by the World Mosquito Program at Monash University in Australia and Indonesia’s Gadjah Mada University.

Previous trials involving Wolbachia – commonly found in fruit flies and other insects – also showed positive results in reducing dengue cases, researchers said.

Studies have also shown the Wolbachia method can be effective in preventing the transmission of Zika, chikungunya, yellow fever and other mosquito-borne illnesses, researchers said.