1 Hilary Ranson, Liverpool School of Tropical MedicineNovember 2009 Insecticide resistance and malaria control

2 Why do we need insecticides for malaria control? Malaria kills over 1 million each year Mostly pregnant women and children >90 % of disease burden is in Africa Increasing drug resistance No vaccine Prevent mosquito transmission of parasite

3 Most malaria mosquitoes in Africa feed indoors, at night = opportunity for control

4 Success stories with IRS and LLINs Bednet use vs. malaria incidence, Eritrea Nyarango et al, Malaria J Malaria decline, Gambia, Ceesay et al, The Lancet, 2009

5 Scale-up of use of insecticide treated bednets: Noor et al, Lancet, : 1.8 % children under 5 protected 2007: 18.5 % children under 5 protected Target = 80 % by 2015

6 Very limited number of insecticides available for public health No new class of insecticide for public health since 1970s, Many insecticides withdrawn Only pyrethroids available for use on bednets DDT Lindane malathion fenitrothionpropoxur chlorpyrifos-methyl pirimiphos-methylbendiocarbpermethrin cypermethrin alpha-cypermethrincyfluthrinlambda-cyhalothrindeltamethrinbifenthrin etofenprox

7 Monitoring for resistance in the field

8 Chad Burkina Faso Bongor 2008/2009 Koupela 2008/2009

9 Insecticide concentrations that a decade ago would kill 100 % of a mosquito population are now readily achieving much much lower levels of mortality Spread of resistance is accelerating in areas with high coverage of insecticide treated bednets or indoor spraying.

10 Monitoring and Evaluation of Insecticide based malaria control programmes TDR network NIH ANVR IVCC IIR WHO/BMGF MTC PMI

11 Is resistance causing control failure? Pyrethroids failed to control malaria vectors on Bioko Island

12 Reduced Efficacy of Insecticide-treated Nets and Indoor Residual Spraying for Malaria Control in Pyrethroid Resistance Area, Benin Raphael N'Guessan et al, EID, 2007 Malanville: North Benin, pyrethroid susceptible. Personal protection from bednets: 97.2% Ladji: Cotonou, high resistance to pyrethroids. Personal protection from bednets: 44.6 % Reduced efficacy of bednets and IRS in Benin

13 A Public/Private Partnership for Vector Innovations Novel Vector Control Chemicals Improved Delivery of Insecticides through Novel Formulations New Decision Support Systems for Vector Control _________________________________ Innovative Vector Control Consortium

14 Delivery of effective tools is the biggest obstacle to malaria control Cannot allow resistance to compromise efficacy of existing tools before they reach areas where most needed

15 Conclusions and recommendations Insecticide resistance is widespread in malaria vectors Growing evidence that this is negatively impacting on malaria control As malaria control is scaled up, situation could deteriorate very rapidly. Urgent need for new insecticides for malaria control Improved monitoring of insecticide resistance needed to enable evidence-based decisions on appropriate insecticide selection Research into strategies to maintain efficacy of existing insecticides must be accelerated