Insecticide resistance in Aedes aegypti populations from Ceará, Brazil

BackgroundOrganophosphates and pyrethroids are used widely in Brazil to control Aedes aegypti, the main vector of dengue viruses, under the auspices of the National Programme for Dengue Control. Resistance to these insecticides is widespread throughout Brazil. In Ceará the vector is present in 98% of districts and resistance to temephos has been reported previously. Here we measure resistance to temephos and the pyrethroid cypermethrin in three populations from Ceará and use biochemical and molecular assays to characterise resistance mechanisms.ResultsResistance to temephos varied widely across the three studied populations, with resistance ratios (RR95) of 7.2, 30 and 192.7 in Juazeiro do Norte, Barbalha and Crato respectively. The high levels of resistance detected in Barbalha and Crato (RR95 ≥ 30) imply a reduction of temephos efficacy, and indeed in simulated field tests reduced effectiveness was observed for the Barbalha population. Two populations (Crato and Barbalha) were also resistant to cypermethrin, whilst Juazeiro do Norte showed only an altered susceptibility. The Ile1011Met kdr mutation was detected in all three populations and Val1016Ile in Crato and Juazeiro do Norte. 1011Met was significantly associated with resistance to cypermethrin in the Crato population. Biochemical tests showed that only the activity of esterases and GSTs, among the tested detoxification enzymes, was altered in these populations when compared with the Rockefeller strain.ConclusionsOur results demonstrate that two A. aegypti populations from Ceará are under strong selection pressure by temephos, compromising the field effectiveness of this organophosphate. Our results also provide evidence that the process of reducing resistance to this larvicide in the field is difficult and slow and may require more than seven years for reversal. In addition, we show resistance to cypermethrin in two of the three populations studied, and for the first time the presence of the allele 1016Ile in mosquito populations from northeastern Brazil. A significant association between 1011M et and resistance was observed in one of the populations. Target-site mechanisms seem not to be implicated in temephos resistance, reinforcing the idea that for the studied populations, detoxification enzymes most likely play a major role in the resistance to this insecticide.

[1]  S. Rawlins.  Spatial distribution of insecticide resistance in Caribbean populations of Aedes aegypti and its significance. , 1998, Revista panamericana de salud publica = Pan American journal of public health.

[2]  A. Devonshire,et al.  A sodium channel point mutation is associated with resistance to DDT and pyrethroid insecticides in the peach‐potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) , 1999, Insect molecular biology.

[3]  J. Hemingway,et al.  A mutation in the voltage‐gated sodium channel gene associated with pyrethroid resistance in Latin American Aedes aegypti , 2007, Insect molecular biology.

[4]  T. Scott,et al.  Dispersal of the dengue vector Aedes aegypti within and between rural communities. , 2005, The American journal of tropical medicine and hygiene.

[5]  J. McAllister,et al.  Simplification of adult mosquito bioassays through use of time-mortality determinations in glass bottles. , 1998, Journal of the American Mosquito Control Association.

[6]  A. Peixoto,et al.  Frequency of Val1016Ile mutation in the voltage‐gated sodium channel gene of Aedes aegypti Brazilian populations , 2009, Tropical medicine & international health : TM & IH.

[7]  G. Georghiou,et al.  Selection and characterization of temephos resistance in a population of Aedes aegypti from Tortola, British Virgin Islands. , 1999, Journal of the American Mosquito Control Association.

[8]  N. Dégallier,et al.  [Susceptibility of Aedes aegypti larvae to the insecticide temephos in the Federal District, Brazil]. , 2004, Revista de saude publica.

[9]  A. Martins,et al.  Insecticide resistance mechanisms of Brazilian Aedes aegypti populations from 2001 to 2004. , 2007, The American journal of tropical medicine and hygiene.

[10]  J. Hemingway,et al.  Identification and analysis of Single Nucleotide Polymorphisms (SNPs) in the mosquito Anopheles funestus, malaria vector , 2007, BMC Genomics.

[11]  M. Macoris,et al.  [Changes in susceptibility of Aedes aegypti to organophosphates in municipalities in the state of São Paulo, Brazil]. , 1999, Revista de saude publica.

[12]  E. Walker,et al.  A simplified high-throughput method for pyrethroid knock-down resistance (kdr) detection in Anopheles gambiae , 2005, Malaria Journal.

[13]  J. Hemingway,et al.  Identification of a point mutation in the voltage‐gated sodium channel gene of Kenyan Anopheles gambiae associated with resistance to DDT and pyrethroids , 2000, Insect molecular biology.

[14]  L. Milá,et al.  Niveles de resistencia a insecticidas y sus mecanismos en una cepa de Aedes aegypti de Santiago de Cuba , 1999 .

[15]  J. Hemingway,et al.  The spread of the Leu‐Phe kdr mutation through Anopheles gambiae complex in Burkina Faso: genetic introgression and de novo phenomena , 2004, Tropical medicine & international health : TM & IH.

[16]  Ima Aparecida Braga,et al.  Aedes aegypti: vigilância, monitoramento da resistência e alternativas de controle no Brasil , 2007 .

[17]  J. Hemingway,et al.  Expression of the cytochrome P450s, CYP6P3 and CYP6M2 are significantly elevated in multiple pyrethroid resistant populations of Anopheles gambiae s.s. from Southern Benin and Nigeria , 2008, BMC Genomics.

[18]  G. Georghiou,et al.  Characterization of resistance to organophosphate, carbamate, and pyrethroid insecticides in field populations of Aedes aegypti from Venezuela. , 1995, Journal of the American Mosquito Control Association.

[19]  P. Usherwood,et al.  The molecular interactions of pyrethroid insecticides with insect and mammalian sodium channels. , 2001, Pest management science.

[20]  A. Devonshire,et al.  Molecular characterization of pyrethroid knockdown resistance (kdr) in the major malaria vector Anopheles gambiae s.s. , 1998, Insect molecular biology.

[21]  J. Morgan,et al.  Pyrethroid Resistance in an Anopheles funestus Population from Uganda , 2010, PloS one.

[22]  J. Bisset,et al.  PYRETHROID INSECTICIDE-RESISTANT STRAIN OF AEDES AEGYPTI FROM CUBA INDUCED BY DELTAMETHRIN SELECTION , 2005, Journal of the American Mosquito Control Association.

[23]  M. D. L. G. Macoris,et al.  Alteração de resposta de suscetibilidade de Aedes aegypti a inseticidas organofosforados em municípios do Estado de São Paulo, Brasil , 1999 .

[24]  J. Busvine.  Mechanism of Resistance to Insecticide in Houseflies , 1951, Nature.

[25]  Janet Hemingway,et al.  The molecular basis of insecticide resistance in mosquitoes. , 2004, Insect biochemistry and molecular biology.

[26]  David Weetman,et al.  Does kdr genotype predict insecticide-resistance phenotype in mosquitoes? , 2009, Trends in parasitology.

[27]  B. D. Saúde..  Dengue: instruções para pessoal de combate ao vetor: manual de normas técnicas , 2001 .

[28]  W. Brogdon,et al.  Monitoring of resistance to the pyrethroid cypermethrin in Brazilian Aedes aegypti (Diptera: Culicidae) populations collected between 2001 and 2003. , 2005, Memorias do Instituto Oswaldo Cruz.

[29]  E. B. Beserra,et al.  [Resistance of Aedes aegypti (L.) (Diptera: Culicidae) populations to organophosphates temephos in the Paraíba State, Brazil]. , 2007, Neotropical entomology.

[30]  E. Lima,et al.  Resistência do Aedes aegypti ao temefós em Municípios do Estado do Ceará , 2006 .

[31]  Mark Daly,et al.  Haploview: analysis and visualization of LD and haplotype maps , 2005, Bioinform..

[32]  P. Somboon,et al.  A novel F1552/C1552 point mutation in the Aedes aegypti voltage-gated sodium channel gene associated with permethrin resistance , 2010 .

[33]  R. W. Fay,et al.  A preferred oviposition site as a surveillance method for Aedes aegypti. , 1966 .

[34]  M. Macoris,et al.  Resistance of Aedes aegypti from the state of São Paulo, Brazil, to organophosphates insecticides. , 2003, Memorias do Instituto Oswaldo Cruz.

[35]  Mazzarri Mb,et al.  Characterization of resistance to organophosphate, carbamate, and pyrethroid insecticides in field populations of Aedes aegypti from Venezuela. , 1995 .

[36]  W. Brogdon,et al.  Association of insecticide use and alteration on Aedes aegypti susceptibility status. , 2007, Memorias do Instituto Oswaldo Cruz.

[37]  H. Ranson,et al.  Transcription profiling of a recently colonised pyrethroid resistant Anopheles gambiae strain from Ghana , 2007, BMC Genomics.

[38]  J. B. Lima,et al.  Aedes aegypti resistance to temephos during 2001 in several municipalities in the states of Rio de Janeiro, Sergipe, and Alagoas, Brazil. , 2004, Memorias do Instituto Oswaldo Cruz.

[39]  J. Morgan,et al.  Field-Caught Permethrin-Resistant Anopheles gambiae Overexpress CYP6P3, a P450 That Metabolises Pyrethroids , 2008, PLoS genetics.

[40]  J. Morgan,et al.  Pyrethroid and DDT cross‐resistance in Aedes aegypti is correlated with novel mutations in the voltage‐gated sodium channel gene , 2003, Medical and veterinary entomology.

[41]  J. Linss,et al.  Voltage-gated sodium channel polymorphism and metabolic resistance in pyrethroid-resistant Aedes aegypti from Brazil. , 2009, The American journal of tropical medicine and hygiene.

[42]  Haichuan Wang,et al.  Kdr allelic variation in pyrethroid resistant mosquitoes, Culex quinquefasciatus (S.). , 2006, Biochemical and biophysical research communications.

[43]  J. Pinto,et al.  Field, genetic, and modeling approaches show strong positive selection acting upon an insecticide resistance mutation in Anopheles gambiae s.s. , 2010, Molecular biology and evolution.

[44]  H. Ranson,et al.  Development and application of a simple colorimetric assay reveals widespread distribution of sodium channel mutations in Thai populations of Aedes aegypti. , 2008, Acta tropica.

[45]  J. Hemingway,et al.  Characterization of knockdown resistance in DDT‐ and pyrethroid‐resistant Culex quinquefasciatus populations from Sri Lanka , 2008, Tropical medicine & international health : TM & IH.

[46]  Luciano Pamplona de Góes Cavalcanti,et al.  [Aedes aegypti resistance to temefos in counties of Ceará State]. , 2006, Revista da Sociedade Brasileira de Medicina Tropical.

[47]  A. Galardo,et al.  Resistance of Aedes aegypti to organophosphates in several municipalities in the State of Rio de Janeiro and Espírito Santo, Brazil. , 2003, The American journal of tropical medicine and hygiene.

[48]  T. Magalhaes,et al.  Resistance to the organophosphate temephos: mechanisms, evolution and reversion in an Aedes aegypti laboratory strain from Brazil. , 2010, Acta tropica.

[49]  A. Solé-Cava,et al.  Genetic structure of natural populations of Aedes aegypti at the micro- and macrogeographic levels in Brazil. , 2004, Journal of the American Mosquito Control Association.

[50]  D. M. Soderlund,et al.  The molecular biology of knockdown resistance to pyrethroid insecticides. , 2003, Insect biochemistry and molecular biology.

[51]  Ima Aparecida Braga,et al.  Aedes aegypti: inseticidas, mecanismos de ação e resistência , 2007 .

[52]  J. Hemingway,et al.  Recent Rapid Rise of a Permethrin Knock Down Resistance Allele in Aedes aegypti in México , 2009, PLoS neglected tropical diseases.

[53]  S. Dai,et al.  A novel amino acid substitution in a voltage-gated sodium channel is associated with knockdown resistance to permethrin in Aedes aegypti. , 2009, Insect biochemistry and molecular biology.

[54]  M. Navarro-Silva,et al.  [Susceptibility of Aedes aegypti to temephos and cypermethrin insecticides, Brazil]. , 2004, Revista de saude publica.

[55]  J. Pinto,et al.  Polymorphism of intron‐1 in the voltage‐gated sodium channel gene of Anopheles gambiae s.s. populations from Cameroon with emphasis on insecticide knockdown resistance mutations , 2009, Molecular ecology.