By Wagdy Sawahel
Science - Education | Health
27 March 2007- Scientists say that genetically modified (GM) mosquitoes, whose young die early in development, could provide a powerful means for combating dengue fever and other mosquito-borne diseases.
Sterile insects have been used for over 50 years to control
or eliminate pests or disease-carrying insects such as the tsetse fly. But
methods to produce sterilisation, such as radiation, are inefficient.
In research published in the journal BMC Biology last week (20 March),
researchers genetically modified Aedes aegypti mosquitoes - which spread dengue
and yellow fever virus - to carry genes that cause offspring to die either early
in their development or at the later larval or pupal stages.
The researchers say that the gene causing death at the later stages of
development was most effective at reducing the populations.
They mathematically modelled the impact these mosquitoes would have on a
mosquito population in the wild.
The results indicated that by spreading the lethal genes, and ensuring that the
offspring die before causing harm, GM mosquitoes could effectively reduce the
wild mosquito population — and thus transmission of the dengue virus — in areas
where the disease is prevalent.
"Controlling Aedes aegypti would help in the fight against chikungunya and
yellow fever as well," says S. Vasan, a visiting research fellow at Oxford
University, United Kingdom.
"With reasonable funding, this technology can also be extended to control other
important [disease-carrying] mosquitoes including Aedes albopictus and Anopheles
species."
Vasan told the science media 'SciDev.Net' that the mosquitoes have been tested
at the Pasteur Institute in Paris, France.
He added that extensive testing was already taking place at a World Health
Organization centre in Kuala Lumpur, Malaysia, and that India's Review Committee
on GM is examining a proposal to conduct small-scale trials.
Paul Reiter, head of the Insects and Infectious Disease Unit at the Pasteur
Institute, welcomed the development, indicating that novel approaches are
urgently required to replace traditional insecticidal approaches that have
little, if any, impact on disease transmission.
Dengue fever is endemic in more than 100 countries in Africa, the Americas, the
eastern Mediterranean, southeast Asia and the western Pacific. The World Health
Organisation estimates there may be 50 million cases of dengue infection
worldwide every year.
© afrol News / SciDev.Net
http://www.afrol.com/articles/24870
