Have Oxitec’s mosquitoes been tested in outdoor urban environments?

Yes. Oxitec and its collaborators have performed open field release tests of Oxitec’s Aedes aegypti (under permit from the regulators) in several countries (including the Cayman Islands, Malaysia and Brazil) from 2009.  In each trial aimed at suppressing the native Aedes aegypti population, Oxitec mosquitoes reduced the local population by over 90%. There have been no noted adverse events or effects.

Another example of outdoor release of a genetically engineered insect is the pink bollworm (Pectinophora gossypiella), a moth that is a pest of cotton.  The US Department of Agriculture has evaluated Oxitec’s GM pink bollworms in three years of open-field and mass-rearing trials, and so far have released over 15 million GM moths in the USA. Oxitec’s strain has performed exactly as predicted in these trials. There have been no negative outcomes (whether environmental, agricultural or to human health) detected.  These trials were also subject to rigorous evaluation by the US regulatory authorities before any release occurred.

Further reading:

Harris, A. F., Nimmo, D., McKemey, A. R., Kelly, N., Scaife, S., Beech, C., Petrie, W., and Alphey, L. (2011) Field performance of engineered male mosquitoes. Nature Biotechnology 29: 1034-1037.

Simmons, G. S., A. R. McKemey, et al. (2011). “Field performance of a genetically engineered strain of pink bollworm.” PLoS One 6(9): e24110.There are several related experiments that have occurred in the past.