Dengue fever and its more serious form, dengue hemorrhagic fever, are caused by dengue viruses. Dengue viruses are transmitted when female mosquitoes of the genus Aedes (primarily Ae. aegypti) feed on an infected human host, amplify the viruses and then subsequently bite an uninfected person. The disease is most prevalent in equatorial regions of the developing world where mosquito and human populations are dense. Approximately 100 million cases occur every year. There is no vaccine available yet to prevent this disease. More information can be found about dengue on the CDC Dengue Fever web site.
A project initiated in 2005 as part of the Grand Challenges in Global Health program sought to apply genetic techniques to control the transmission of dengue viruses. Approaches for both reducing vector population densities and modifying their capacity to transmit viruses were based on transgenic mosquito technologies. A 'flight-less female' strain was developed and tested for its abilty to suppress wild-type populations. Strains of mosquitoes incapable of transmitting a specific serotype, dengue 2 viruses, were developed. Also, a team of researchers with expertise in mosquito genetics, virology, computer modeling and ethical/cultural/social considerations was able to take a population suppression approach from the laboratory to large cage trials in a country endemic for dengue. Scientific efforts on the project concluded in 2013 and this web site provides a brief summary of the accomplishments and publications.
The adult female mosquito is responsible for transmitting dengue viruses among humans. The male mosquito is incapable of taking a blood meal and therefore of transmitting disease.