Work Package 2: Controlling insecticide resistant populations

LSTM logo Swiss Tropical and Public Health Institute/ Centre Suisse de Recherche Scientifique CSRS LOGO NIMR (1) University of Crete CNRFP Logo IVCC logo CNRS  

 

WP2 Group

Work Package Leader: Dr John Vontas. University of Crete 

 

 

Objectives:

 

 

Tasks

 Progress/plans

  

To characterise the causes and extent of insecticide resistance in malaria vectors in the AvecNet field sites and identify and validate genes responsible for insecticide resistance

Work in this task was largely accomplished by Ako Constant EdiToé Kobie Hyacinthe and Theresia Nkya, 3 of our PhD candidates who have all now successfully defended their work and been conferred the title of Dr.  In addition to identifying the mechanisms responsible for insecticide resistance in three different countries, and identifying sources of selection pressure, work in this task also highlighted the impact of resistance on current control tools and the limitations of current bioassays for measuring this impact. A follow on study comparing alternative bioassay methods for quantifying resistance has been published

Ongoing work includes following up on some novel insecticide resistance candidate genes that have been identified by a meta analysis of multiple data sets characterising pyrethroid resistant populations across Africa.

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To develop new and improved tools to detect insecticide resistance in Africa: develop of a field applicable tool for vector population and resistance monitoring

UoC and LSTM have been evaluating an antibody based approach to detect metabolic resistance to insecticides in the field.Results so far suggest that this will not be sufficiently sensitive to detect elevated activities of P450s responsible for insecticide metabolism in individual mosquitoes. However promising results have recently been obtained using antibodies raised against P450s putatively involved in production of the outer waxy layer of the insect’s cuticle; this is being pursued as a potential new diagnostic for a cuticular resistance mechanism.

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Laboratory evaluation of new insecticidal compounds against mosquito populations resistant to current insecticides

 

 

AvecNet works in partnership with the Liverpool Insecticide Testing Establishment (LITE)  to evaluate new insecticidal products provided by IVCC’s industrial partners. 

Multiple new colonies of insecticide resistant populations of An gambiae from Cote d’Ivoire and Burkina Faso (Tiassale, VK7 and Banfora) have been established in the insectaries at LITE and each year over 60,000 mosqutioes have been screened for evaluation of new insecticide products. 

The results of these bioassays are being utilized by insecticide manufacturers (including BASF, Bayer CropScience, Syngenta and Sumitomo) to optimise the development of new chemical entities or formulations.   Three new active ingredients have now passed this initial screening phase and are moving to the next phase of the product development pipeline.  Screening compounds against multiple resistant populations can help detect potential problems of cross resistance earlier in the product development pipeline, saving time and resources.

STPHI have been investigating the major sources of variability in insecticide bioassay results including the impact of larval density, food availability and temperature.  In addition they have compared results from WHO tube susceptibility test and CDC bottle bioassays. Both of these assays are widely used in the field and two recent AvecNet publications shed light on the difficulties in directly comparing results obtained with alternative methodologies.

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Experimental Field evaluation (hut trials) of new insecticidal formulations 

 

18 new experimental huts have been constructed in Tiassale, Cote d'Ivoire and Banfora, Burkina Faso. Formulations provided by the Industrial Partners of IVCC are being tested under field conditions in three sites: VK7, Burkina Faso, Tiassale, Cote d'Ivoire and Muheza, Tanzania. A number of products have been evaluated in short six week studies but only those meeting the strict stage-gate translation process set by AvecNet are proceeding to longer term evaluations. 

Training sessions in Quality Assurance for Experimental Hut Studies have been delivered by IVCC  and considerable investment has also been made in statistical and quantitative skills needed for experimental hut studies9

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Publications & Outputs 

Deodatus V. Maliti, Nicodem J. Govella, Gerry F. Killeen, Nosrat Mirzai, Paul C. D. Johnson, Katharina Kreppel and Heather M. Ferguson. Development and evaluation of mosquito-electrocuting traps as alternatives to the human landing catch technique for sampling host-seeking malaria vectors. Malaria Journal 2015 14:502

H. Ranson and N. Lissenden. Insecticide Resistance in African Anopheles Mosquitoes: A Worsening Situation that Needs Urgent Action to Maintain Malaria Control. Science Direct Volume 32, Issue 3, March 2016, Pages 187–196 Special Issue: Vectors

H. F. Owusu; D.Jančáryová; D. Malone and P. Müller. Comparability between insecticide resistance bioassays for mosquito vectors: time to review current methodology? Parasites & Vectors (2015) 8:357

J. Bagi; N. Grisales; R. Corkill; J. C. Morgan; S. N’Falé; W. G. Brogdon and H. Ranson. When a discriminating dose assay is not enough: measuring the intensity of insecticide resistance in malaria vectors. Malaria Journal 2015, 14:210

H. K. Toé; S. N’Falé; R. K. Dabiré; H. Ranson and C. M. Jones. The recent escalation in strength of pyrethroid resistance in Anopheles coluzzi in West Africa is linked to increased expression of multiple gene families. BMC Genomics (2015) 16:146

H. K. Toé; C. M. Jones; S. N’Fale; H. M. Ismail; R. K. Dabiré and H.Ranson. Increased Pyrethroid Resistance in Malaria Vectors and Decreased Bed Net Effectiveness, Burkina Faso. Emerging Infectious Diseases, Volume 20, Number 10, October 2014

Theresia E Nkya, Rodolphe Poupardin, Frederic Laporte, Idir Akouayri, Franklin Mosha, Stephen Magesa, William Kisinza and Jean-Philippe David. Impact of agriculture on the selection of insecticide resistance in the malaria vector Anopheles gambiae: a multigenerational study in controlled conditions. Parasites and Vectors 2014. 7:480

J. P. David; H. M. Ismail; A. Chandor-Proust and M. J. Ingraham - PaineRole of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth. Philosophical Transactions of the Royal Society B: Biological Sciences 2013, 1612 (368) 

T. E. Nkya; I. Akhouayri; W. Kisinza and J.P. David. Impact of environment on mosquito response to pyrethroid insecticides. Facts, evidences and prospects. Insect Biochemistry and Molecular Biology. 2012 42 (10) 729-826

C. A. Edi; B. G. Koudou; C. M. Jones; D. Weetman and H. Ranson. Multiple-Insecticide Resistance in Anopheles gambiae Mosquitoes, Southern Côte d’Ivoire. Emerging Infectious Diseases. 2012 18 (9)  1508 -1511

C. M. Jones; M. Liyanapathirana; F. R. Agossa; D. Weetman; H. Ranson; M. J. Donnelly and C. S. Wilding. Footprints of positive selection associated with a mutation (N1575Y) in the voltage-gated sodium channel of Anopheles gambiae. Proceedings of the National Academy of Sciences of the United States. 2012. 109 (17) 6614 - 6619

C. A. Edi; B. G. Koudou;  M. Chouaibou; B. Bonfoh;  S. Dongus; S. J. E. Barry; P. C. D. Johnson; P. Müller; H. Ranson and D. Weetman. Long-term trends in Anopheles gambiae insecticide resistance in Côte d’Ivoire, Parasites & Vectors 2014, 7:500

G. Papadakis; A. Tsortos; A. Kordas; I. Tiniakou; E. Morou and J. Vontas. Acoustic detection of DNA conformation in genetic assays combined with PCR. Scientific Reports 2013 VOL 3, Article number 2033

C. M. Jones; K. A. Haji; B. O. Khatib; J. Bagi; J. Mcha; G. J. Devine; M. Daley; B. Kabula; A. S. Ali; S. Majambere and H. Ranson. The dynamics of pyrethroid resistance in Anopheles arabiensis from Zanzibar and an assessment of the underlying genetic basis. Parasites and Vectors. 2013 6:343

T. E. Nkya;  I. Akhouayri; R. Poupardin; B. Batengana; F. Mosha; S. Magesa; W. Kisinza and J. P. David. Insecticide Resistance mechanisms associated with different environments in the malaria vector Anopheles gambiae: a case study in Tanzania. Malaria Journal 2014 Volume 13

H. RansonFacing the resistance crisis in malaria control by developing and evaluating ‘resistance-breaking’ products. Outlooks in Pest Management. February 2014. p.33