Pipeline Technology from Oxitec Ltd: Genetic Control of Mosquito Vectors and Crop Pests

Mosquito-borne diseases such as Zika, dengue fever and Chikungunya are major and increasing international public health concerns. The primary vector of these viral diseases is Aedes aegypti and current control measures against this mosquito are proving inadequate or problematic. An innovative and effective control technique for Aedes aegypti involves the release of self-limiting mosquitoes. These mosquitoes are genetically engineered to be homozygous for a self-limiting gene under control of an on/off tetracycline switch. When released into the wild, any offspring of the transgenic males will inherit one copy of the transgene. In the absence of tetracycline antidote, the transgene will prevent the mosquito from developing to adulthood, thus suppressing the population with repeated releases. Oxitec’s self-limiting transgenic insect technology has also been applied successfully to develop population control measures for major crop pests such as the Mediterranean fruit fly (Medfly) and the diamondback moth. In a variation on the self-limiting genetics used in Aedes mosquitoes, genetic sexing strains that express the self-limiting gene in a sex-specific manner are used to produce male-only cohorts of these crop pests for release in control programmes. These and other developments in Oxitec’s genetic engineering programme to enable biological control of major insect pests will be discussed. The Oxitec transgenic mosquito method has dramatically reduced Aedes aegypti populations in trials around the world and is now being used under operational conditions in the Cayman Islands and Brazil to control Aedes aegypti. Results of these programmes will be presented.