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Jun. 9, 2021 , 5:00 PM
A strategy for fighting dengue fever with bacteria-armed mosquitoes has passed its most rigorous test yet: a large, randomized, controlled trial. Researchers reported today dramatic reductions in rates of dengue infection and hospitalization in areas of an Indonesian city where the disease-fighting mosquitoes were released. The team expects the World Health Organization (WHO) to formally recommend the approach for broader use.
The findings are a “breakthrough” that brings the approach “much closer to … being an official strategy to control dengue,” says Ewa Chrostek, an infection biologist at the University of Liverpool who was not involved with the work. WHO estimates there are 100 million to 400 million infections per year with dengue, which can cause high fever and severe joint pain.
The bacterium Wolbachia pipientis naturally inhabits many insects, though not Aedes aegypti mosquitoes, the main transmitter of dengue virus. In A. aegypti cells, the bacterium can block viruses, including dengue, from replicating, making the insects less likely to spread disease when they bite humans. That has made the microbe a promising strategy for fighting dengue. In tropical regions, where mosquito-borne viruses are common, other strategies such as insecticides have failed to fully control the disease.
A few previous studies have found that areas where Wolbachia mosquitoes were released had lowered rates of dengue compared with nearby untreated areas, or with historical infection rates. But, “The global scientific community was looking for gold-standard evidence, and that means a randomized trial,” says Cameron Simmons, an infectious disease researcher at Monash University, Melbourne, and an investigator with the nonprofit World Mosquito Program (WMP), which conducted the new study.
For that gold-standard trial, the researchers divided a 26-square-kilometer area in Yogyakarta, Indonesia—an urban area home to about 300,000 people—into 24 clusters. In 12 of those clusters, the team set out containers of Wolbachia-carrying mosquito eggs every 2 weeks for 18 to 28 weeks. The microbe eventually spread through the local mosquito population: Ten months after releases started, the prevalence of Wolbachia among mosquitoes in the treated clusters had climbed to 80% or higher.
A strategy for fighting dengue fever with bacteria-armed mosquitoes has passed its most rigorous test yet: a large, randomized, controlled trial. Researchers reported today dramatic reductions in rates of dengue infection and hospitalization in areas of an Indonesian city where the disease-fighting mosquitoes were released. The team expects the World Health Organization (WHO) to formally recommend the approach for broader use.
The findings are a “breakthrough” that brings the approach “much closer to … being an official strategy to control dengue,” says Ewa Chrostek, an infection biologist at the University of Liverpool who was not involved with the work. WHO estimates there are 100 million to 400 million infections per year with dengue, which can cause high fever and severe joint pain.
The bacterium Wolbachia pipientis naturally inhabits many insects, though not Aedes aegypti mosquitoes, the main transmitter of dengue virus. In A. aegypti cells, the bacterium can block viruses, including dengue, from replicating, making the insects less likely to spread disease when they bite humans. That has made the microbe a promising strategy for fighting dengue. In tropical regions, where mosquito-borne viruses are common, other strategies such as insecticides have failed to fully control the disease.
A few previous studies have found that areas where Wolbachia mosquitoes were released had lowered rates of dengue compared with nearby untreated areas, or with historical infection rates. But, “The global scientific community was looking for gold-standard evidence, and that means a randomized trial,” says Cameron Simmons, an infectious disease researcher at Monash University, Melbourne, and an investigator with the nonprofit World Mosquito Program (WMP), which conducted the new study.
For that gold-standard trial, the researchers divided a 26-square-kilometer area in Yogyakarta, Indonesia—an urban area home to about 300,000 people—into 24 clusters. In 12 of those clusters, the team set out containers of Wolbachia-carrying mosquito eggs every 2 weeks for 18 to 28 weeks. The microbe eventually spread through the local mosquito population: Ten months after releases started, the prevalence of Wolbachia among mosquitoes in the treated clusters had climbed to 80% or higher.
