Mosquitoes sterilised in bid to help stop the spread of dengue fever, zika virus

Australian scientists say the initial results of a project to desex deadly mosquitoes are promising. Researchers have released more than 1 million sterile Aedes aegypti mosquitoes in several communities near Innisfail, south of Cairns, in far north Queensland. The mosquitoes, which are native to Africa, are responsible for spreading diseases like dengue fever and the zika virus. Project leader Nigel Beebe from the CSIRO said they were aiming to become the first in the world to completely eradicate the mosquitoes from an urban landscape. “We are very, very happy with the technology, very happy with the mass production and the results are looking very encouraging,” Dr Beebe said. “There’s no doubt we are seeing a significant reduction in the number of Aedes aegypti mosquitoes in those trial and control sites.” Scientists have been breeding millions of mosquitoes in laboratory conditions at James Cook University in Cairns through the Debug project, which is being funded by Google’s sister company Verily. The mosquitoes are infected with the Wolbachia bacteria, which renders the male mosquitoes sterile. The insects are then released into the wild at the trial sites. Dr Beebe said male mosquitoes did not bite or spread disease, but when infected with the bacteria they played havoc with female mosquitoes’ reproductive systems. “When the male that has the bacteria mates with a female that does not have the bacteria, it becomes incompatible and the embryo dies,” Dr Beebe said. “Essentially these mosquitoes become sterile and if you can release lots of these boy mosquitoes that carry the bacteria, you can shut down the population.” It is not the first-time researchers have infected mosquitoes with the Wolbachia bacteria in order to stop the spread of disease. Scientists have been releasing infected mosquitoes in the Cairns region since 2011. Dr Beebe said the earlier project replaced mosquito populations with insects that could not transmit viruses, but his research used male mosquitoes to remove the population entirely. Dr Beebe said his project could have far-reaching implications. “We’d look into regions of the world that needed assistance in controlling their mosquitoes,” Dr Beebe said. “In the Torres Strait Islands, we have Asian tiger mosquitoes which also can transmit dengue and zika. “It is an incredibly aggressive mosquito and models suggest that it will make its way down to Melbourne. “So, we’d love to try to focus the technology on that mosquito so we can remove it from the Torres Strait Islands.”

ABC Science News, 15 April 2018 ;

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