Download Egyptian method of mosquito control

SCPA606 March 16-25, 2015: Infectious Diseases / RU, GD
Interest grows in unusual Egyptian method of mosquito control
“The innovative method utilises the rays of the African sun to contain the disease.”
El-Tayeb, Cairo University
Remark for the thoughts
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Somalia and South Sudan are keen on using the technique to cut malaria
It uses chlorophyll powder and sunlight to kill mosquito larvae
But there are reservations about large-scale implementation
[CAIRO] Plans are progressing to introduce an unusual method of mosquito
control which involves sprinkling powdered plant extracts on swampy mosquito
nurseries. The Egyptian researchers behind the innovation have set up a
company to develop the method and recently signed an agreement with South
Sudan’s government to implement the technique there.
The researchers, whose firm is called InRaD (Innovative Research and
Development), tell SciDev.Net that they have also had requests from Somalia’s
health ministry to do the same.
Later this month, Mahmoud Abdel-Kader, a photochemist at the German
University in Cairo, Egypt, and one of the two scientists behind the technique,
is due to fly to Switzerland to present the results of laboratory and field
research to the WHO. He says he is planning on discussing the possibility of
WHO approval of the method.
“The innovative method utilises the rays of the African sun to contain the
disease.”
El-Tayeb, Cairo University
The technique involves adding a derivative of the plant pigment chlorophyll to
wetlands infested with the aquatic larvae of mosquitoes.
Abdel-Kader’s collaborator, Tarek El-Tayeb, a biologist at Cairo University,
says: “We extracted the chlorophyll from green plants and transformed it into a
powder which was sprinkled in places where the larvae are found.
“The larvae climb to the surface of the water for oxygen. Then they feed on the
powder, which has been manufactured to float on the surface.”
In plants, El-Tayeb says, chlorophyll absorbs sunlight and passes on its energy
so that plants can build their sugary fuels from carbon dioxide. But in its
powdered form, the chlorophyll instead transfers the sun’s energy to dissolved
oxygen inside the larvae. The resulting form of oxygen is unstable and so
reacts with the cells’ components, damaging them and ultimately killing the
larvae.
The research included three years of laboratory work as well as field
experiments in the wetlands of Ethiopia, Sudan and Uganda that are full of
malaria-transmitting mosquitoes. The technique killed between 85 to 100 per
cent of larvae, according to a poster summary published in Malaria Journal in
2012.
As well as the Anopheles mosquitoes that are a vector for malaria, the
technique kills the Aedes mosquito, which pass on dengue fever. And it kills the
Culex mosquito, which transmits parasitic worms that cause a disease called
filariasis.
“The innovative method utilises the rays of the African sun to contain the
disease,” says El-Tayeb. “It’s a natural method that causes no environmental
damage.”
For instance, the Uganda experiments showed no effect on the natural
predators such as dragonfly larvae that feed on mosquito larvae.
Muhammad Raja’i, an entomologist at the National Centre for Research in
Egypt, tells SciDev.Net that, compared with other biologically safe techniques,
this method is “less expensive and more effective at exterminating mosquitoes”.
But there are concerns about its practical application.
Abd al-Majid al-Gharib, a physical chemist at Cairo University, tells SciDev.Net:
“I am confident the idea is successful on a small scale, but deploying the
powder on every canal, drainage ditch and wetland to control malaria [would
be] extremely difficult.”
Yet El-Tayeb says: “The powder is effective for 21 days and the extraction
process itself is not expensive at all. We should consider large-scale
implementation.”