New Developments in Vector Control Insecticide Resistance and Natural Product Development Janet McAllister Centers for Disease Control and Prevention Fort Collins, CO "The findings and conclusions in this presentation are those of the author and do not necessarily represent the views of the Centers for Disease Control and Prevention."

Public Education and Community Outreach Resistance Monitoring Physical Control Biological Control Chemical Control Disease Surveillance Mapping Mosquito Sampling and Surveillance Legal Actions

Resistance Issues What is it? When will it arrive? Once it’s here that’s it for that chemical/class. How do I know I have it? What do I do? What roles do outside forces play in selection for resistance? Where do I go for help?

Areawide Mosquito Adulticides ChemicalClassYearuses MalathionOP1950 Crops, livestock, home, ornamental, forest, public health NaledOP1960 Crops, livestock, ornamental, greenhouses, forest, public health ChlorpyriphosOP1966 Crops, home, stored products, public health ResmethrinPY1968 House, ornamental, livestock premisis, public health SumethrinPY1971 House, greenhouses, livestock premisis, ornamentals, public health PermethrinPY1974 Crops, livestock, public health, ornamentals, greenhouses PyrethrinsPY*ca1828 Crops, livestock, home, public health, ornamentals, pets, food handling establishments

What’s it all mean to a mosquito control district: The problem Current application rate of resmethrin was not killing mosquitoes in some parts of Harris county No knowledge of what rate to use for alternative pyrethroids Field testing is cost and labor intensive and traditional resistance tests have never been correlated to field results

Harris County Mosquito Control District Adulticide Usage Timeline

SLE and WNV Mosquitoes

Initial field-trial results from Area 51

Materials for Bottle Bioassay.

Insecticides vary in the rate in which they intoxicate mosquitoes An. freeborni

Wiebull Distribution with frailty model and interval sensing components Change in area 205 from 2005 to 2006

Steps to field test mosquitoes

Field Study Site in Harris County

Mortality of Culex quinquefasciatus in field and bottle tests from Area 51

Mortality of Culex quinquefasciatus in caged field trials

Objectives Is there a correlation between results from field tests for resistance and bottle bioassays? Help characterize the resistance mechanism(s) involved in resistance to pyrethroids in Harris County.

Enzyme results – area 109 Oxidase levels not significantly different Esterase levels are significantly higher

Malathion mechanism expression from area 109

Esterase + Oxidase Esterase Oxidase + Esterase Esterase + Oxidase

The plan for now Alternate highest rate of Resmethrin with Malathion If Resmethrin totally fails, switch to permethrin Incorporate yearly resistance testing to determine when changes in treatment scheme need to happen Re-evaluate how to test for resistance

Malathion susceptibility from field tests – data with both years

Still to go Correlation between types of test? Data “manipulation” still underway Mapping of mechanisms Multiple mechanisms detected from different foci, mapping still underway More intense collecting from selected areas to see how resistance genes are distributed with more precise resolution How is rotation of chemicals affecting control?

Area 51 collection sites as of Aug 2006 and treatment history 2004 – 5 treatments with Scourage ® 2005 – 13 treatments with Scourage ® and 13 with Fyfanon ® 2006 – 7 treatments with Scourage ® and 8 with Fyfanon ®

New Chemicals for Control? Incense Cedar Thymoquinone Pure Incense Cedar Nootkatone Carvacrol Others Vanillin D-limonene Alaskan yellow cedar Nootkatone Nootkatol Carvacrol 13-hydroxy-valencene Valencene-13-aldehyde Pure Alaskan yellow cedar Nootkatene Nootkatone-1,10-11,12- diepoxide Valencene5 Cadinene fraction Vanillin D-limonene

Monoterpene and Eromophilane Sesquiterpenes Isolated from Alaska Yellow Cedar NOOTKATOL

Previous Work Tick repellent and toxicity tests 1 st small scale field trials in NJ in 2006 against larval and adult Ticks Formulated with all 25b inerts Initial screening for mosquito repellency and toxicity

Intrinsic Toxicity of AYC and IC components

Natural products – Intrinsic Toxicity compared to common insecticides SpeciesInsecticideLD50 (ng/mg) LD95 (ng/mg) Py ratio Ae.aegyptiMalathion Permethrin pyrethrum Thymoquinone Carvacrol Incense cedar Cx. quinq.Malathion Permethrin pyrethrum thymoquinone carvacrol Incense cedar

MOA Study Design Natural Product Topical Application to Mosquitoes An. gambiae G3 susceptible base-line An. gambiae MRA-698 Na+ channel mutation An. gambiae MRA-116 GABA mutation ??? Octopamine mutation Culex? ACHE mutation

See if you can find your way through this perplexing maze! Start Finish

Immediate Next Steps Fill in a few gaps with An. gambiae Mode of Action study with An. gambiae Field “feasibility” study – minimal formulation Shop for a partner with industry Other ideas???

Thanks to: Joe Piesman and Marc Dolan, CDC Joe Karchesy, Oregon State University Harris Co. Mosquito Control