Transcript New Developments in Vector Control

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
Physical
Control
Disease
Surveillance
Resistance Monitoring
Biological
Chemical
Control
Control
Legal Actions
Mapping
Mosquito Sampling and Surveillance
Resistance Issues
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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
Chemical
Class
Year
uses
Malathion
OP
1950
Crops, livestock, home,
ornamental, forest, public health
Naled
OP
1960
Crops, livestock, ornamental,
greenhouses, forest, public
health
Chlorpyriphos
OP
1966
Crops, home, stored products,
public health
Resmethrin
PY
1968
House, ornamental, livestock
premisis, public health
Sumethrin
PY
1971
House, greenhouses, livestock
premisis, ornamentals, public
health
Permethrin
PY
1974
Crops, livestock, public health,
ornamentals, greenhouses
Pyrethrins
PY*
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
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Harris County Mosquito Control District
Adulticide Usage Timeline 1965-2004
SLE and WNV Mosquitoes
Initial field-trial results from Area 51
Percent Mortality
45
40
35
30
25
20
15
10
5
0
Scourge
Scourge
Anvil 10:10 Perm-X .003
.003 lb/acre .007 lb/acre .003 lb/acre
lb/acre
Materials for Bottle Bioassay.
Percent Mortality
Insecticides vary in the rate in
which they intoxicate mosquitoes
100
90
80
70
60
50
40
30
20
10
0
Malathion
Fenthion
Resmethrin
Permethrin
Naled
Temephos
An. freeborni
0
15
30
45
time (min.)
60
75
90
Wiebull Distribution with frailty model and
interval sensing components
2005
2006
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
80
60
40
20
0
Sumethrin
Permethrin Resmethrin
Field Tests
Bottle Tests
Mortality of Culex quinquefasciatus
in caged field trials
100
80
60
40
20
0
Area 51 Area 55 Area 67
Malathion
Permethrin
Sumethrin
Resmethrin
Objectives
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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
a esterases in Cx. quinquefasciatus
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20
frequency
Oxidase levels not
significantly different
 Esterase levels are
significantly higher
15
10
5
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
absorbance (x 0.1)
colony
b esterases in Cx. quinquefasciatus
Oxidases in Cx. quinquefasciatus
15
frequency
30
frequency
area 109
20
10
0
10
5
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
absorbance (x 0.1)
colony
area 109
1
4
7 10 13 16 19 22 25 28 31 34 37 40
absorbance (x 0.1)
colony
area 109
Percent Mortality
Malathion mechanism expression
from area 109
100
90
80
70
60
50
40
30
20
10
0
Malathion
Mal + PBO
Mal + DEF
0
15
30
Time (min.)
45
60
Esterase
Oxidase +
Esterase
Oxidase
Esterase +
Oxidase
Esterase +
Esterase +
The plan for now- 2005-2008
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
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Malathion susceptibility from field
tests – data with both years
100
90
80
70
60
50
40
30
20
10
0
51
53
55
2005
67
2006
520
Average
721
936
Still to go
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Correlation between types of test?
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Mapping of mechanisms
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Data “manipulation” still underway
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®
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New Chemicals for Control?
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Incense Cedar
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Thymoquinone
Pure Incense Cedar
Nootkatone
Carvacrol
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Alaskan yellow cedar
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Others
 Vanillin
 D-limonene
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Nootkatone
Nootkatol
Carvacrol
13-hydroxy-valencene
Valencene-13-aldehyde
Pure Alaskan yellow
cedar
Nootkatene
Nootkatone-1,10-11,12diepoxide
Valencene5
Cadinene fraction
Vanillin
D-limonene
Monoterpene and Eromophilane Sesquiterpenes
Isolated from Alaska Yellow Cedar
NOOTKATOL
Previous Work
 Tick
repellent and toxicity tests
 1st small scale field trials in NJ in
2006 against larval and adult
Ticks
 Formulated
 Initial
with all 25b inerts
screening for mosquito
repellency and toxicity
LC 50 (mg/ml)
500
450
400
350
300
250
200
150
100
50
0
Ae. aegypti
Cx. quinq.
d-Limonene
Vanillin
Cadinene Fraction
Valencene 5
Nootkatone-1,1011,12-dieposide
Nootkatene
pure AYC
Valencene-13aldehyde
Nootkatol
Nootkatone 1-10
epoxide
13hydroxyvalencene
Nootkatone 8
Nootkatone
crystalline
Nootkatone
powder
Incense Cedar
Carvacrol
Thymoquinone
Intrinsic Toxicity of AYC and IC
components
0
Ae. aegypti
Cx. quinq.
pure AYC
Valencene-13aldehyde
Nootkatol
Nootkatone 8
Nootkatone
crystalline
Nootkatone powder
Incense Cedar
Carvacrol
Thymoquinone
Pyrethrum
LC 50 (mg/ml)
Intrinsic Toxicity of AYC and IC
components
50
64
40
30
20
10
.09 .06
Natural products – Intrinsic Toxicity
compared to common insecticides
Species
Insecticide
LD50
(ng/mg)
LD95
(ng/mg)
Py ratio
Ae.aegypti
Malathion
1.5
3.51
0.15
Permethrin
18.2
156
1.8
pyrethrum
10.1
39.8
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Thymoquinone
631
1765
62
Carvacrol
1206
2273
119
Incense cedar
1251
2148
124
Malathion
3.53
7
0.66
Permethrin
3.18
15
0.60
pyrethrum
5.32
13.5
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thymoquinone
355
635
67
carvacrol
857
1450
161
Incense cedar
748
1366
141
Cx. quinq.
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