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Oxford, England — Oxitec scientists have reported the creation of a new flightless strain of the Asian tiger mosquito, Aedes albopictus. The breakthrough, reported in the journal PLoS Neglected Tropical Diseases, could help stop the spread of this dangerous and invasive pest.
The Asian tiger mosquito is a serious nuisance biter, but is also capable of transmitting dengue fever, Chikungunya, West Nile Virus and a host of other diseases. In the last few decades it has spread throughout the world and is now established in many regions, including Europe and the US, where it is becoming both an extremely bothersome pest and an increasing health concern.
Dr. Randy Gaugler, Director of the Center for Vector Biology at Rutgers University in New Brunswick, USA explains the threat. “The Asian tiger mosquito is an extremely aggressive biter prominent in the global surge in new and emerging vector-borne diseases. The public health threat from this mosquito, particularly with regard to transmission of dengue and chikungunya, is of concern to health professionals because there are no vaccines or chemo-prophylaxis to treat infection. Suppressing the mosquitoes that transmit the viruses is the only available approach. Conventional control strategies against this species have been moderately effective at best. A new paradigm is needed.”
The Asian tiger mosquito is an extremely difficult pest to control: conventional methods rely on chemical pesticides which not only harm other insects but are increasingly ineffective as mosquitoes develop resistance.
Now, an Oxitec team led by Dr Genevieve Labbe has pioneered a new approach. The team has genetically modified the mosquitoes with a ‘flightless’ gene so that the females are unable to fly. Oxitec releases male mosquitoes carrying the flightless gene: male mosquitoes can’t bite or spread diseases, and when Oxitec males mate with wild females, their flightless daughters are unable to feed or reproduce, and soon die. Successive releases will lead to a rapid reduction in the overall population of these mosquitoes in an area.
Commenting on the breakthrough, Oxitec Chief Scientific Officer Dr Luke Alphey said:
“We believe this is an intelligent response to this invasive pest. These mosquitoes and their breeding sites are hard for humans to find, which limits the effectiveness of conventional control methods. So instead we are harnessing the natural drive of a male mosquito to seek out a female. It’s not only an effective strategy but an environmentally sound one too: the mosquitoes only mate with their own species so, in contrast to pesticides, non-target insects are not harmed. Removing this mosquito would cause minimal environmental disruption, not least because it is a very recent invasive species in most areas.
The flightless mosquito strain is an adaptation of Oxitec’s genetically ‘sterile’ mosquitoes, which have already been successfully demonstrated in Grand Cayman and Brazil, reducing target populations of the dengue mosquito, Aedes aegypti.