This means that Far North Queensland is essentially dengue-free for the first time in well over 100 years, according to Dr Richard Gair, Director and Public Health Physician, Tropical Public Health Services Cairns.

Short-term releases of Wolbachia mosquitoes were undertaken up to 8 years ago in some communities, and monitoring in these areas has shown that Wolbachia has since remained in the local mosquitoes with no further releases required. Importantly, there has been reduced dengue transmission in these areas, with a 93 per cent reduction in reported dengue cases. This follows the 5-year success of the World Mosquito Program method in the city of Townsville.

World Mosquito Program Director and Monash University Professor Scott O’Neill is thrilled with the result.

“We’ve seen almost the complete collapse of locally acquired dengue in previously high-risk transmission areas in cities and communities across Australia’s far north, despite imported dengue cases continuing to rise. In fact, local dengue transmission has essentially disappeared from Cairns for the first time since the early 1980s.”

Local Wolbachia-mosquito populations were established using a variety of methods, including direct involvement of school children, householders, community groups and businesses, who assisted with growing and releasing Wolbachia mosquitoes. 

These mosquitoes were deployed across a total resident population of 165,000 including a staggered deployment in the Cairns region from 2011 to 2017, and into the urban areas of the Cassowary Coast, Charters Towers and Douglas regions in 2016 and 2017.

Ongoing long-term monitoring will establish whether these communities have been ‘dengue-proofed’ and whether the protection extends to other mosquito-borne viruses like those that cause Zika, chikungunya and yellow fever.

This work was supported by residents of Cairns and surrounding communities, the Bill & Melinda Gates Foundation, the Wellcome Trust, the Queensland Government and the Gillespie Family Foundation.

Titled, ‘Establishment of wMel Wolbachia in Aedes aegypti mosquitoes and reduction of local dengue transmission in Cairns and surrounding locations in northern Queensland, Australia’, the paper can be accessed on Gates Open Research.