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X Substitution Target population 1 3/21/2016 Control of Aedes - PDF document

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3/21/2016 Fiocruz Instituto Oswaldo Cruz Chemical control & insectiside resistance Ademir J Martins Jr Macei, march 13 th 2016 Control of insect populations Suppression X Substitution Target population 1 3/21/2016 Control of Aedes

  1. 3/21/2016 Fiocruz Instituto Oswaldo Cruz Chemical control & insectiside resistance Ademir J Martins Jr Maceió, march 13 th 2016 Control of insect populations Suppression X Substitution Target population 1

  2. 3/21/2016 Control of Aedes aegypti Suppression populations Avoid larval Mechanical control breeding sites predators/ parasites transgenesis Wolbachia Biological control SIT paratransgenesis genetic shifting Chemical control insecticides Substitution Control of Aedes aegypti Suppression populations Avoid larval Mechanical control breeding sites predators/ parasites transgenesis Wolbachia Biological control SIT paratransgenesis genetic shifting Chemical control insecticides Substitution 2

  3. 3/21/2016 Bass et al 2014 – Insect Biochem Mol Biol Insecticides The Brazilian National Program for Dengue Control only applies insecticides approved by the WHO Pesticide Evaluation Scheme (WHOPES) updated 5 February 2016 3

  4. 3/21/2016 Insecticides The Brazilian National Program for Dengue Control only applies insecticides approved by the WHO Pesticide Evaluation Scheme (WHOPES) Bio N IGR IGR IGR N N N N updated 5 February 2016 Insecticides The Brazilian National Program for Dengue Control only applies insecticides approved by the WHO Pesticide Evaluation Scheme (WHOPES) Pyr Pyr OP Pyr Pyr updated 5 February 2016 4

  5. 3/21/2016 Insecticides The Brazilian National Program for Dengue Control only applies insecticides approved by the WHO Pesticide Evaluation Scheme (WHOPES) updated 5 February 2016 Insecticides against Ae. aegypti In Brazil - Larvicide temephos (OP) and adulticides fenitrothion and malathion (OPs) until 2009 - Resistance to OPs started being detected in1998 - Inauguration of a National Monitoring Network for Insecticide Resistance in Aedes aegypti - Substitution of the larvicide to Bti (biol), JH and BPUs IGRs and the adulticides to deltamethrin (Pyr) - Soon after, resistance to Pyr was detected and then we returned to the OP malathion . 5

  6. 3/21/2016 Insecticides against Ae. aegypti In Brazil - Larvicide temephos (OP) and adulticides fenitrothion and malathion (OPs) until 2009 - Resistance to OPs started being detected in 1998 - Inauguration of a National Monitoring Network for Insecticide Resistance in Aedes aegypti - Substitution of the larvicide to Bti (biol), JH and BPUs IGRs and the adulticides to deltamethrin (Pyr) - Soon after, resistance to Pyr was detected and then we returned to the OP malathion . Currently indicated by the Brazilian National Program for Dengue Control Larvicide: pyriproxyfen (JH) Adulticides: malathion (OP) – spatial bendiocarb (CA) – residual 6

  7. 3/21/2016 Insecticide resistance can contribute to an increase in the incidence of arboviruses Insecticide resistance can contribute to an increase in the incidence of arboviruses Exemple: reduced mortality of Ae. aegypti to pyrethroids showed a significant correlation with dengue incidence in localities from São Paulo 70 P. Prudente R 2 = 0.7372, p <0.0286 60 mortality (%) Marília Rib. Preto 50 Campinas SJR Preto 40 Santos 30 0 5000 10000 15000 20000 25000 cumulative dengue incidence Macoris, not published 7

  8. 3/21/2016 Insecticide resistance in dengue vectors Ranson et al 2010, TropiKanet Insecticide resistance in dengue vectors Ranson et al 2010, TropiKanet 8

  9. 3/21/2016 source: IR Mapper 2005 – 2015 published data on Anopheles resistance How to evaluate insecticide resistance? 9

  10. 3/21/2016 How to evaluate insecticide resistance?  There is an increasing number of validated methods for evaluating insecticide resistance levels and their selected physiological mechanisms How to evaluate insecticide resistance? Bioassays CDC bottle bioassay WHO tubes bioassay 10

  11. 3/21/2016 Main mechanisms selected for insecticide resistance Behavioral Reduced penetration changes (cuticle) Increase in enzymatic detoxification Target site insensitivity How to evaluate insecticide resistance? Biochemical and Biochemical assays of enzymatic activity molecular assays 11

  12. 3/21/2016 Mechanisms for insecticide resistance: metabolic resistance in Aedes aegypti from Brazil High-throughput identification of resistance genes Faucon et al 2015 – Genome Research 12

  13. 3/21/2016 Mechanisms for insecticide resistance: kdr mutations in Aedes aegypti from Brazil - Wide genome analysis (GWAS) comparing susceptible and resistant individuals of several Brazilian populations Bioasays with insecticide Resistant Susceptible Aedes aegypti SNP chip Aedes aegypti SNP chip Evans et al 2015 – Genes, - 32K biallelic, mendelian and validated Genomics, Genetics SNPs for each individual in one reaction 13

  14. 3/21/2016 Worldwide insecticide resistance network in mosquito vectors of arboviruses Acronym: WIN (Worldwide Insecticide-resistance Network) PI’s: Vincent Corbel (IRD, Thailand) and Jean-Philippe David (CNRS, France) The WIN proposes to bring together 15 internationally recognized institutions in vector research, providing a unique framework for tracking insecticide resistance in mosquito vectors of arboviruses around the world. The network aims at identifying the particular countries/regions where resistance could challenge vector control interventions and to provide the WHO and member states with key recommendations for improvement of insecticide resistance surveillance and deployment of alternative vector control tools. Would we able to continue effectively using insecticides as one of the alternatives for vector control ??? Is it possible to revert to a susceptible stage? 14

  15. 3/21/2016 Selection pressure insecticide Is it possible to revert to a susceptible stage? time - Comparisons between Rock and Rock- kdr (R2R2)  Time of larval development R2 kdr allele has a Pupation rate fitness cost Adults longevity Circadian rhythm  Locomotor activity Blood feeding Fecundity: rate of inseminated females  Fecundity: number of eggs Fertility: eggs’ viability  Competition during larval development Competition for copula 15

  16. 3/21/2016 - Comparisons between Rock and Rock- kdr (R2R2)  Time of larval development R2 kdr allele has a Pupation rate fitness cost Adults longevity Circadian rhythm  Locomotor activity Blood feeding Fecundity: rate of inseminated females Enough to diminish  Fecundity: number of eggs the frequency of the mutant allele in an Fertility: eggs’ viability insecticide-free  Competition during larval development environment ? Competition for copula A cage 1 1.0 cage 2 1016 Ile (frequecy) 0.8 cage 3 R2 kdr allele has a 0.6 0.4 fitness cost 0.2 0.0 0 3 6 9 12 15 generations (F) B cage 4 1.0 cage 5 1016 Ile (frequecy) 50% 0.8 cage 6 0.6 75% 0.4 Kdr allele initial frequency (3 independent cages for each situation) 0.2 0.0 0 3 6 9 12 15 generations (F) 16

  17. 3/21/2016 A cage 1 1.0 cage 2 1016 Ile (frequecy) 0.8 cage 3 R2 kdr allele has a 0.6 0.4 fitness cost 0.2 0.0 0 3 6 9 12 15 generations (F) B cage 4 1.0 cage 5 1016 Ile (frequecy) 50% 0.8 cage 6 0.6 75% Kdr allele initial frequency 0.4 (3 independent cages for each situation) 0.2 0.0 0 3 6 9 12 15 generations (F) Awareness modifier genes 17

  18. 3/21/2016 Conclusions - Insecticide resistance has become a serious threaten to mosquito control. Merely switching insecticide when the current one no longer works is not effective. - Good predictions of the dynamics of resistance in natural populations have to consider the knowledge of genetic, biologic and ecological aspects of the selected mechanisms. Remarks for studying a resistant population Challange #1 : knowledge of the selected mechanisms - Metabolic - target site - cuticle thickening - behavioural Challenge #2 : knowledge of the dynamics of resistance genes in the population - R allele frequencies - dominance relationships - epistatic effects on fitness Avoid the increase and dispersion of resistance Avoid cross resistance among different class of insecticides Maintain insecticides as one of the possible strategies for mosquito control 18

  19. 3/21/2016 Thank you! Ademir J Martins ademirjr@ioc.fiocruz.br 19

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