In a world-first, Australian researchers have eliminated dengue fever outbreaks in the north Queensland city of Townsville through the large-scale deployment of specially modified mosquitoes.
About four million Aedes aegypti mosquitoes infected with a strain of Wolbachia bacteria, which is found naturally in up to 60% of insect species and renders them incapable of transmitting viruses, were released in areas of the city where breeding was most likely to occur.
The Wolbachia deployment, across 66km2, began in October 2014 and lasted 28 months, with strong community support and participation from Townsville’s 187,000 residents.
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Between November 2014 and June 2018, only four locally acquired dengue cases were identified, compared with a usual rate of around 10-50 cases a year.
The drop in local cases was significant because it occurred during a period when imported cases of dengue, mostly from international travellers, increased.
Co-author Professor Scott Ritchie from James Cook University said the trial essentially meant the researchers and Queensland Health were “dengue-proofing” the country.
“It’s a vaccine for mosquitoes that’s delivered by the mosquitoes themselves,” Professor Ritchie told Australian Doctor.
He said that once Wolbachia was established in a mosquito population, it would spread and maintain itself without the need for more mosquito releases.
“It’s a clever way of doing it. It’s probably far and away the cheapest way of disease control I’ve seen for this kind of stuff in all my years of working on this,” said Professor Ritchie.
Lead author Professor Scott O’Neill, director of the World Mosquito Program, said the success of the trial suggested that Wolbachia-infected mosquitoes could be deployed effectively across large areas at low cost.
“We believe our approach will be suitable for other cities, with appropriate local adaptation, and provides a framework for scaling-up our deployment, globally,” said Professor O’Neill, who is also director of the Institute of Vector-Borne Disease at Monash University.
He said the cost of the Townsville trial, which was about $15 per person, could likely be reduced to $1 per person when deployed in tropical cities with much higher population densities.
The study has been published on the Gates Open Research platform and is awaiting peer review.
Professor O’Neill said community engagement proved to be crucial to the trial’s success, with particular attention given to raising awareness among locals and encouraging them to become active participants in the program.
The modified mosquitos were also released in Port Douglas, Mossman and along the Cassowary Coast. Results from these trials are yet to be published.
Since the Townsville trial started in late 2014, the World Mosquito Program has been expanded to 11 other countries, including Indonesia, Brazil and Colombia.
More information:
Gates Open Research website
About four million Aedes aegypti mosquitoes infected with a strain of Wolbachia bacteria, which is found naturally in up to 60% of insect species and renders them incapable of transmitting viruses, were released in areas of the city where breeding was most likely to occur.
The Wolbachia deployment, across 66km2, began in October 2014 and lasted 28 months, with strong community support and participation from Townsville’s 187,000 residents.
Read more:
Between November 2014 and June 2018, only four locally acquired dengue cases were identified, compared with a usual rate of around 10-50 cases a year.
The drop in local cases was significant because it occurred during a period when imported cases of dengue, mostly from international travellers, increased.
Co-author Professor Scott Ritchie from James Cook University said the trial essentially meant the researchers and Queensland Health were “dengue-proofing” the country.
“It’s a vaccine for mosquitoes that’s delivered by the mosquitoes themselves,” Professor Ritchie told Australian Doctor.
He said that once Wolbachia was established in a mosquito population, it would spread and maintain itself without the need for more mosquito releases.
“It’s a clever way of doing it. It’s probably far and away the cheapest way of disease control I’ve seen for this kind of stuff in all my years of working on this,” said Professor Ritchie.
Lead author Professor Scott O’Neill, director of the World Mosquito Program, said the success of the trial suggested that Wolbachia-infected mosquitoes could be deployed effectively across large areas at low cost.
“We believe our approach will be suitable for other cities, with appropriate local adaptation, and provides a framework for scaling-up our deployment, globally,” said Professor O’Neill, who is also director of the Institute of Vector-Borne Disease at Monash University.
He said the cost of the Townsville trial, which was about $15 per person, could likely be reduced to $1 per person when deployed in tropical cities with much higher population densities.
The study has been published on the Gates Open Research platform and is awaiting peer review.
Professor O’Neill said community engagement proved to be crucial to the trial’s success, with particular attention given to raising awareness among locals and encouraging them to become active participants in the program.
The modified mosquitos were also released in Port Douglas, Mossman and along the Cassowary Coast. Results from these trials are yet to be published.
Since the Townsville trial started in late 2014, the World Mosquito Program has been expanded to 11 other countries, including Indonesia, Brazil and Colombia.
More information:
Gates Open Research website
