How it works

OX513A is a self-limiting strain of the Aedes aegypti mosquito. Males, which do not bite or transmit disease, are released to mate with wild females. The offspring of such matings die before becoming adults. With repeated releases of sufficient numbers of these self-limiting males, there is a reduction in the wild population to below the level needed to transmit disease according to models of disease transmission.

Before release, male and female pupae are separated mechanically, exploiting the fact that naturally they are significantly different in size. The strain also contains a fluorescent marker, termed DsRed, which is a useful tool for quality control in production and effective monitoring in the field.

Performance in evaluation

Five efficacy trials have taken place in Brazil, Panama, and the Cayman Islands. These have all demonstrated that releases of Oxitec’s self-limiting mosquitoes results in reduction of the wild population by more than 90% – an unparalleled level of control.

OX513A has also been successfully evaluated at a number of laboratories including at the Institut Pasteur in Paris and at the WHO Collaborating Centre for Vectors at the Institute for Medical Research (IMR) in Malaysia. OX513A has demonstrated stable performance over 150 generations.


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 the Cayman Islands, Panama, Brazil and Malaysia. Projects are currently taking place in Brazil and Grand Cayman, and a trial planned for the Florida Keys recently received a preliminary finding of no significant impact from the Food and Drug Administration.