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Record ID
Date of creation
2012-05-11 20:07 UTC (dina.abdelhakim@cbd.int)
Date of publication
2012-05-11 20:07 UTC (dina.abdelhakim@cbd.int)

General Information
Towards a sterile insect technique field release of Anopheles arabiensis mosquitoes in Sudan: irradiation, transportation, and field cage experimentation
Michelle EH Helinski, Mo'awia M Hassan, Waleed M El-Motasim, Colin A Malcolm1, Bart GJ Knols and Badria El-Sayed
Author’s contact information
Michelle EH Helinski
Email: michellehelinski@hotmail.com
  • English
Publication date
Summary, abstract or table of contents

Background: The work described in this article forms part of a study to suppress a population of the malaria vector Anopheles arabiensis in Northern State, Sudan, with the Sterile Insect Technique. No data have previously been collected on the irradiation and transportation of anopheline mosquitoes in Africa, and the first series of attempts to do this in Sudan are reported here. In addition, experiments in a large field cage under near-natural conditions are described.

Methods: Mosquitoes were irradiated in Khartoum and transported as adults by air to the field site earmarked for future releases (400 km from the laboratory). The field cage was prepared for experiments by creating resting sites with favourable conditions. The mating and survival of (irradiated) laboratory males and field-collected males was studied in the field cage, and two small-scale competition experiments were performed.

Results: Minor problems were experienced with the irradiation of insects, mostly associated with the absence of a rearing facility in close proximity to the irradiation source. The small-scale transportation of adult mosquitoes to the release site resulted in minimal mortality (< 6%). Experiments in the field cage showed that mating occurred in high frequencies (i.e. an average of 60% insemination of females after one or two nights of mating), and laboratory reared males (i.e. sixty generations) were able to inseminate wild females at rates comparable to wild males. Based on wing length data, there was no size preference of males for mates. Survival of mosquitoes  from the cage, based on recapture after mating, was satisfactory and approximately 60% of the insects were recaptured after one night. Only limited information on male competitiveness was  obtained due to problems associated  with individual egg laying of small numbers of wild females.

Conclusion: It is concluded that although conditions are challenging, there are no major obstacles associated with the small-scale irradiation and transportation of insects in the current setting. The field cage is suitable for experiments and studies to test the competitiveness of irradiated males can be pursued. The scaling up of procedures to accommodate much larger numbers of insects needed for a release  is the next challenge and recommendations to further implementation of this genetic control strategy are presented.
Thematic areas
  • Scientific and technical issues
    • Risk assessment
Background material to the “Guidance on risk assessment of living modified organisms”
Is this document is recommend as background material for the “Guidance on Risk Assessment of Living Modified Organisms”
Section(s) of the “Guidance on Risk Assessment of Living Modified Organisms” this background material is relevant
  • 5. Risk assessment of living modified mosquitoes species that act as vectors of human and animal diseases
Additional Information
Type of resource
  • Article (journal / magazine / newspaper)
Publisher and its location
Biomed Central
© 2008 Helinski et al
10 page PDF
Malaria Journal
Keywords and any other relevant information
Citation: Malaria Journal 2008, 7:65