Dengue fever is one of the most virulent mosquito-borne diseases afflicting the planet. According to the World Health Organization (WHO), 2.5 billion people worldwide are currently at risk of contracting dengue, and the organization estimates that there may be 50–100 million new infections each year. However, The Associated Press reports that scientists are now releasing dengue-resistant mosquitos into Vietnam in the hopes of curbing the spread of the disease. The key is engineering the mosquitoes to carry Wolbachia, a bacteria that prevents dengue from being transmitted.

Wolbachia infects the cells of up to 70 percent of the world’s insects. Research has shown that it also prevents the replication of diseases like yellow fever, West Nile, and dengue. However, mosquitos like Aedes aegypti, well known for spreading disease, don’t naturally carry the bacteria. After much painstaking work and research, scientists found a way to, instead, implant the bacteria into mosquitos to induce the infection and pass it onto offspring. The result was a breed of mosquito that can’t carry dengue and spread it to healthy people.

The new breed of mosquito was shipped from Australia to Tri Nguyen Island, Vietnam to infiltrate the native population and test how well it works at preventing the spread of the disease in dengue-endemic regions. The next step is sustaining the batches of Wolbachia in the wild. Researchers are also doing similar work with malaria, though treating it is harder because more than one species of mosquito is known to carry it. However, this approach shows great promise for finding new ways to treat illness globally.

"I've been working with [dengue fever] now for 40-something years, and we have failed miserably," Duane Gubler, a dengue expert at the Duke-NUS Graduate Medical School in Singapore, told the AP. "We are now coming into a very exciting period where I think we'll be able to control the disease. I really do."