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MALARIA VECTOR SUSCEPTIBILITY IN RWANDA. 1ST RWANDA MALARIA FORUM RESULTS 2010-2011.

MALARIA VECTOR SUSCEPTIBILITY IN RWANDA. 1ST RWANDA MALARIA FORUM RESULTS 2010-2011. By Emmanuel Hakizimana September 27 th , 2012. INTRODUCTION. Rwanda is strongly committed towards malaria control with the ultimate goal of eliminating this disease .

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MALARIA VECTOR SUSCEPTIBILITY IN RWANDA. 1ST RWANDA MALARIA FORUM RESULTS 2010-2011.

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  1. MALARIA VECTOR SUSCEPTIBILITY IN RWANDA. 1ST RWANDA MALARIA FORUM RESULTS 2010-2011. By Emmanuel Hakizimana September 27th, 2012

  2. INTRODUCTION • Rwanda is strongly committed towards malaria control with the ultimategoal of eliminating this disease. • Vector control using insecticides is one of thekey componentsof malaria controlstrategies • A significant reduction of morbidity and mortality is achieved when theefficacy of vector control interventions is continuously maintained at ahigh level • The selection of insecticides for use in IRSand LLINsis highly dependent on the extent to which local mosquitoes are susceptible to the approved classes of insecticides.

  3. Background and Rationale (Cont.) • Documented cases of resistance or development of resistance inmosquito populations associated with: – Agriculture (Brogdonet al. 1988b; Chouaibouet al. 2008) – IRS (Brogdon et al. 1988a; Lines, 1988) – ITNs (Vulule et al. 1999; Corbel et al. 2004; Rubaihayo et al.2008) – Use of household insecticides (sprays, coils etc.) (Akogbeto&Yakoubou, 1999) • Since 2009, insecticide resistance monitoring is one of the package of entomology surveillance in sentinel sites with a frequence of once a year.

  4. Objectives • To evaluate the susceptibility of malaria vectors to the main insecticides recommended by WHOand used in country (Deltamethrin, Permethrin, Lambdacyhalothrin, DDT, Fernitrothion, Bendiocarb) in differents ecosytems of Rwanda. • Enlighten scientific recommendation of insecticides for interventions of malaria vector control in Rwanda

  5. Study sites: 14 sites countrywide

  6. Methods – Test procedures • CDC bottles (in 2010) and WHO standards protocol, 1998 (since 2011) • Non-blood fed females of Anopheles gambiae s.l. aged 2-3 days old of the local strains from larvae collected from field and reared in field insectary • Knockdown and mortality rates were recorded at 10, 15, 20, 30, 40, 50, 60 min and 24h post exposure respectively

  7. RESULTS WITH CDC BOTTLES, 2010

  8. Susceptible tests conducted on An. gambiaes.l. in 8 sites with CDC bottle, 2010.

  9. RESULTS WITH WHO STANDARD PROTOCOL (1998)

  10. Time of Knockdown for 6 insecticides tested

  11. Time for 50% knockdown (KDT50)by Deltamethrin 0.05% (Py)

  12. Time for 50% knockdown (KDT50) by Permethrin 0.75% (Pyrethroid)

  13. Time for 50% knockdown (KDT50) by Lambdacyhalothrin 0.75% (Py)

  14. Time for 50% knockdown (KDT50) by DDT 4.0 % (Organochlorines)

  15. Time for 50% knockdown (KDT50) by Bendiocarb 0.1% (Carbamates)

  16. Time for 50% knockdown (KDT50) by Fenitrothion 1.0% (Organophosphates)

  17. Mortality after 24 hrs of exposure

  18. Interpretation of Results • >98% mortality= susceptible • < 95% mortality under optimum conditions with > 100 mosquitoes= strong suspicion of resistance • 80-97 % mortality= resistance suspected; • < 80% mortality= resistant individuals present

  19. National average mortality obtained for six Insecticides

  20. Susceptibility status of A. gambiaes.l. to Pyrethroids (commonly used for vector control)

  21. Susceptibility status of A. gambiaes.l. to to other classes of insecticide

  22. PCR – Identification & kdr gene (Partial Results)

  23. PCR-Identification, 2007-2008

  24. PCR-Identification, 2011

  25. PCR-kdr gene, 2008

  26. PCR-kdr gene, 2011

  27. Conclusion • Until 2011, malaria vectors were more sensitive to lambdacyhalothrin (Pyrethroids) and to Fenitrothion (Organophosphates) • More suspicious of resistance to Pyrethroids. High prevalence of gene KDR which would explain the suspicion of resistance to Pyrethroids • Insecticide resistance has been confirmed in 3 sites with DDT 4% • Occurrence of Anopheles arabiensisas predominant of malaria vectors since 2011 in almost study sites . • Continue susceptibility tests and dynamic of malaria vector species

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