Cases of dengue fever — a deadly mosquito-borne, neglected tropical disease that infects up to 400 million people a year — have been cut by 77% in an astonishing new trial by The World Mosquito Program (WMP).

The trial saw researchers infect mosquitoes with a bacteria called Wolbachia, which successfully hindered the ability of the dengue virus to survive within the insects and subsequently stopped them from transmitting the virus to humans.

A Wolbachia-infected mosquito was shown to only produce offspring that likewise carry the bacteria, meaning that all mosquitoes in a population will eventually be infected.

Researcher Adi Utarini explained that as part of the experiment, the Wolbachia-infected mosquitoes were released in the city of Yogyakarta in Indonesia — a country that is home to more than 7 million dengue cases every year.

Within Yogyakarta, across 27 months, there was an 86% reduction in people requiring hospitalisation due to dengue.

“This is a great success for the people of Yogyakarta,” Utarini said in a statement. “The trial success allows us to expand our work across the entire city of Yogyakarta and into neighbouring urban areas. We think there is a possible future where residents of Indonesian cities can live free of dengue.”

'The study conducted by @WMPglobal@MonashUni, Australia and Indonesia’s @UGMYogyakarta found that infecting dengue-carrying 🦟 with a harmless bacteria called #Wolbachia led to a 7⃣7⃣% drop in human cases.' Read more https://t.co/AUmqe3sYUl via @AlJazeera_World

— World Mosquito Program (WMP) (@WMPglobal) June 14, 2021

Activists, researchers and scientists say the trial’s success is exciting for more than one reason.

Alongside the clear proof that the Wolbachia method works to prevent dengue, WMP Director Scott O’Neill said the trial also provides a clear model that can be copied when addressing other mosquito-borne diseases.

"This is the result we’ve been waiting for,” he said. 

Initial studies have shown the Wolbachia method to successfully prevent the transmission of other diseases like Zika and Yellow Fever, O'Neill explained. The technique, unfortunately, is not thought to work for malaria because a parasite causes the disease in mosquitoes, not a virus. 

The trial will now expand to include Yogyakarta’s surrounding provinces.

Up to 4 million people are hoped to be protected by 2022, with 10,000 infections prevented each subsequent year. 

Researchers say the ultimate goal of eliminating dengue from Yogyakarta, and then the entirety of Indonesia, is possible, as shown by similar trials in Australia, which saw Wolbachia mosquitoes create essentially dengue-free areas across the nation's tropical far north over a 10-year period.