Eradicating Mosquitoes That Carry Dengue Virus Without Chemicals
William (Bill) Perry
Director, Gene Therapy Advanced Technologies at Johnson & Johnson Innovative Medicines
The UK company Oxitec, a spin-out from the University of Oxford, has developed an exciting strategy to eliminate the Aedes aegypti species of mosquitoes- the strain that carries the Dengue virus that causes the deadly Dengue Fever. About 50 million Dengue infections occur annually in areas where 2.5 billion people live (1), and no vaccines or effective treatments exist. New strategies to kill these mosquitoes are urgently needed.
The company has developed a genetically-engineered strain of mosquito that can only survive to adulthood when given tetracycline in their food. Males are produced in large numbers in a factory for release into areas targeted for eradication. When the males mate with normal female mosquitoes in the wild, the eggs she lays self-destruct during development when the dominant lethal gene is activated. Hence, all of her offspring are eliminated. They call this approach RIDL (Release of Insects Containing a Dominant Lethal). Another ingenious feature of their approach is that the RIDL insects express a red-fluorescent protein, so these insects can be easily identified in the field for monitoring their numbers.
There are several obvious advantages of the RIDL approach. It takes advantage of the ability of the males to find females wherever they are, and only this specific insect species is affected as opposed to using chemical pesticides. Since only female insects bite people there should be no chance that the released RIDL insects would cause a direct human health risk. While it may be impossible to actually eliminate an insect species in the wild even if you wanted to, it should be possible to reduce levels to a level too low to support disease transmission.
The company reports that their strain OX513A has regulatory approvals for import and contained testing in Brazil, Cayman Islands, France, India, Malaysia, Singapore, Thailand, USA and Vietnam. Open field trials have taken place in both Grand Cayman and Malaysia, and are currently also underway in Brazil.
Potential for Controlling Other Disease-Spreading Insects and Those Affecting Agriculture?
It may be possible to create RIDL strains of other insect species such as the mosquitoes that carries Malaria, Chikungunya, and the Yellow Fever pathogens. Agricultural pests that may also be targeted include the Diamond back moth, Pink bollworm, Medfly, Mexfly, and Olive fly. Targeted control of these insects without chemical pesticides is an exciting possibility for improving human health in a sustainable way.
Credits:
I first heard about this interesting approach to killing the Aedes aegypti mosquitoes from the Radiolab podcast “KILL 'EM ALL”. I urge you to download and listen to this and other Radiolab podcasts. I am consistently riveted by the stories from hosts Jad Abumrad and Robert Krulwich and their colleagues.
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William L Perry III, Ph.D. is a scientist with over 20 years experience in the pharmaceutical and biotechnology industries discovering the causes of human disease and developing effective medicines. See more articles of interest on his blog published at LinkedIn.com.
Director, Gene Therapy Advanced Technologies at Johnson & Johnson Innovative Medicines
10 年Peter- It might be applicable in those cases as well. However, one needs the ability to breed the animals in the laboratory to large numbers and to create the genetically-engineered animals. But this approach could be widely applicable to many species.
Senior Executive, Corporate Communications
10 年Bill - this is indeed very promising technology and an answer to the overuse/reliance of pesticides. Wondering if the application can be developed to control populations of Pine Beetles and Zebra Mussels.