impact of sub-lethal exposure to insecticides on vector control lee cohnstaedt and sandra allan...

Impact of Sub-Lethal Exposure to Insecticides on Vector Control

Impact of Sub-Lethal Exposure to Insecticides on Vector Control

Lee Cohnstaedt and Sandra AllanUSDA-ARS-CMAVETriservices Meeting

Feburary 2010

Insecticide contact

Pyrethroids

If not dead, then what?

Mosquito species

Behavioral assays

Entrance

Air+CO2

*Capillary release attractant*CO2 release 50ml/min

Attractant

*Infrared light was used illuminate nocturnally active mosquitoes.

*Treatment level lethal dose25

Flight path analysis

Untreated Cx. quinquefasciatus

Deltamethrin treated Cx. quinquefasciatus

Flight path analysis

Untreated An. albimanus

Permethrin treated An. albimanus

Flight path analysis

Treated Ae. aegypti

Untreated Ae. aegypti

Average flight velocity

*

*Velocity

0

20

40

60

80

100

120

Cx quinquefasciatus An albimanus Ae aegpyti

Me

an

ve

loc

ity

(c

m/s

)

Contol Deltamethrin Permethrin

0

1

2

3

4

5

6

7

8

Cx quinquefasciatus An albimanus Ae aegypti

Seco

nd

s

Control Deltamethrin Permethrin

Time in flight

01

23

45

67

8

Cx quinquefasciatus An albimanus Ae aegypti

Se

co

nd

s

Control Deltamethrin Permethrin

* *

Heading

-20

-15

-10

-5

0

5

10

15

20

De

gre

es

Control Detamethrin Permethrin

0

1

2

3

4

5

6

7

8

Cx quinquefasciatus An albimanus Ae aegypti

Seco

nd

s

Control Deltamethrin Permethrin

*

*

0.0%

10.0%

20.0%30.0%

40.0%

50.0%

60.0%

70.0%80.0%

90.0%

100.0%

Cx quinquefaciatus An albimanus Ae aegypti

% B

lood

Fed

Control Permethrin Deltamethrin

Blood feeding

*

0

1

2

3

4

5

6

7

8

Cx quinquefasciatus An albimanus Ae aegypti

Seco

nd

s

Control Deltamethrin Permethrin

Implications

The sublethal affects of

pyrethroids on a mosquito’s

ability to detect and locate

hosts may increase the

efficacy of aerial and

residual spraying treatments

beyond their immediate

killing impact.

Personal protective measures

Band

Sleeve

Phlebotomuspapatasi

Treatment Hand Band SleeveBite

protection

Untreated 20 (29%) 11 (16%) 37 (54%) ---

Sleeve (permethrin) 43 (26%) 40 (24%) 84 (50%) -28.5%

Sleeve (permethrin) + Band (TL-I-73) 129 (27%) 86 (18%) 269 (56%) 16.9%

Band (TL-I-73) 39 (49%) 12 (15%) 28 (35%) 21.8%

Sleeve (permethrin) + Band (UB-21)

27 (40%) 12 (18%) 28 (41%) 94.1%

Number of landings per 20 minutes

Landing site

Band

Sleeve

Implications

Sand flies predominantly

land on the sleeve before

moving towards the

exposed skin; therefore a

lethal insecticidal barrier

at the uniform-skin

interface will reduce

disease transmission.

Acknowledgments• Uli Bernier• Matt Aubuchon

• Adrian Duehl• Erin Vrzal • Nathan Newlon