Release ratios employed for genetically modifying populations of mosquitoes

Abstract

To begin to define the mass of transgenic vector-incompetent mosquitoes that might be required for modifying a natural vector population, the release ratios that have been employed in genetic-control experiments are reviewed. Proposed releases incorporating genetic-drive mechanisms may require somewhat smaller masses of released mosquitoes. Because pathogen-incompetent mosquitoes tend to be less fit than are those in natural target populations, at least as many construct-bearing mosquitoes must be released as are present in the target site at the beginning of the intervention. A series of well documented attempts to reduce the fertility of natural populations of mosquitoes were reported during 1967 through 1982. Those that succeeded generally released more than ten modified mosquitoes for each mosquito present at the time of the release. In the event that the entire vector population of the region is not immediately rendered incapable of supporting the development of the pathogen, some specified prevalence of construct-bearing must indefinitely be sustained there. Existing anti-malaria measures may be incompatible with such an intervention. A successful genetic intervention may require the sustained release of more human-biting mosquitoes than would otherwise be present in the target site