1. NICOLE L. ACHEE Department Preventive Medicine & Biometrics Uniformed Services University of the Health Sciences 10 February 2010 Latest Research On Spatial Repellency for Disease Control Pest Management Workshop

2. Current Global Strategies Uniformed Services University of the Health Sciences Vector makes contact with a chemical source, absorbs insecticide and is killed = “mortality centric”

3. Other Strategies Available Uniformed Services University of the Health Sciences Behavioral Responses for Breaking Man/Vector Contact

4. Why Spatial Repellency? The current vector control dogma is: “the only good mosquito is a dead mosquito”. So what is the advantage to the public health community to repel vectors without killing? Immediate impact: minimize potential for insecticide resistance. Long-term benefit: exploitation of yet undescribed events vectors engage in outside the home pre-, during and post-host seeking to further enhance vector control. Such a paradigm shift from toxic to non-toxic strategies will require clear evidence to the scientific community that: 1) Spatial repellency exists as an action separate from irritancy and toxicity 2) A vector control approach using spatial repellency will impact disease Uniformed Services University of the Health Sciences

5. Does spatial repellency exist as an action separate from contact irritancy and toxicity? Acquiring Evidence : Identifying Chemical Actions Uniformed Services University of the Health Sciences Dose Responses

6. Chemical Actions & Vector Responses Uniformed Services University of the Health Sciences

7. Contact Irritant “PUSH” Spatial Repellent “PUSH” Focal Treatment = Trap Outdoor Trap “PULL” Push-Pull Concept Overview Use minimal dose and targeted coverage (portals of entry/resting sites) to make a house unacceptable

8. Uniformed Services University of the Health Sciences Behavioral Thresholds in the Field Treated netting placed upon interior walls of experimental huts Evaluate using mark-release study design with local vector populations Interception traps capture entering mosquitoes Time and density of mosquito entry recorded as compared to control hut THAILAND

9. Window Calculate total indoor surface area of hut: Use 100,75, 50, 25% coverage ratios of treated material at varying doses Application begins at portal of entry (window) and coverage increases towards center of hut Calculate total indoor surface area of hut: Use 100,75, 50, 25% coverage ratios of treated material at varying doses Application begins at portal of entry (window) and coverage increases towards center of hut Uniformed Services University of the Health Sciences Behavioral Thresholds in Field THAILAND

10. 3 Repetitions (300 ♀) Total Control = 115 Total Treatment = 63 45% Reduction Spatial Repellency Uniformed Services University of the Health Sciences Behavioral Thresholds in Field Control Hut Treatment Hut Treatment: 100% surface area of X at ½ FAR THAILAND

11. Uniformed Services University of the Health Sciences Behavioral Thresholds in Field ChemicalDoseCoverage Entry Effect Product A 1.0100%- 59% 1.050%- 45% 1.025%TBD 0.5100%- 39% 0.550%TBD 0.525%+9% Product B 1.0n/a- 68% 0.5n/a0% Dose refers to material treatment. No measure of chemical dose in air space – is it a SR effect or KD? THAILAND

12. A.I. in Air Column & Behavior Uniformed Services University of the Health Sciences Window Door Air Sampling Points Indoors What is the chemical concentration in air space over distance? Protection range Does this dose elicit SR or KD? OR THAILAND

13. Will a vector control approach using spatial repellency reduce disease? **Must have entomological correlates** Acquiring Evidence: Impact on Disease Uniformed Services University of the Health Sciences Diversion to Untreated Human-Host Locations Incidence of Malaria

14. Diversion to Untreated Areas Uniformed Services University of the Health Sciences THAILAND 45 m Field Station Hut A Hut D Hut C Hut B ? Treat Here Will a SR treated structure cause vectors to move to untreated areas? Shift rather than reduce disease transmission? ? ?

15. Baseline Studies Chemical Studies Total diversion ranged from 3 - 5% during baseline studies (no chemical). Post-treatment, percent moving from treated to control was 4.7% - within the range of random movement without chemical. Uniformed Services University of the Health Sciences Diversion to Untreated Areas Hut Color of Hut A Color of Hut B Color of Hut C Total Diverted A Product X 91/400 23% 13/400 3% 4/400 1% 17/800 2.1% B Control 22/400 6% 140/400 35% 16/400 4% 38/800 4.7% C Product Y 16/400 4% 16/400 4% 45/400 11% 32/800 4.0% THAILAND Hut Color of Hut A Color of Hut B Color of Hut C Total Diverted A Control 156/400 39% 27/400 7% 16/400 4% 43/800 5.4% B Control 12/400 3% 104/400 26% 15/400 4% 27/800 3.3% C Control 11/400 3% 12/400 3% 106/400 27% 23/800 2.9%

16. Hut A Hut B Hut CHut DHut E Treat with Repellent Uniformed Services University of the Health Sciences Diversion to Untreated Areas

17. Disease Impact of SR SUMBA ISLAND, INDONESIA Uniformed Services University of the Health Sciences

18. Malaria Dynamics SUMBA ISLAND, INDONESIA Malaria prevalence as high as 40% and 65% among children <5 years Species distribution: 75% P. falciparum, 22% P. vivax, 3% P. malariae

19. Uniformed Services University of the Health Sciences Traditional Home SUMBA ISLAND, INDONESIA

20. Species: An. sundaicus* An. subpictus An. maculatus An. barbirostris An. vagus Uniformed Services University of the Health Sciences Challenge I: Low vector densities; difficult to measure behavioral effects Malaria Vectors SUMBA ISLAND, INDONESIA

21. Ambigous Indoor/Outdoor Spaces Uniformed Services University of the Health Sciences Challenge II: Open housing structures so must consider 1) site of vector entry and placement of SR product; 2) fluid dynamics on A.I. concentration; 3) entomological collection methodologies “Inside” Room “Outside” Porch

22.  A clear understanding of vector ecology is essential to the development of novel vector control tools – this includes house entry and exit behavior patterns.  Spatial repellency can serve to prevent vectors from entering a specified space occupied by a human host. Quantifying diversion vital component to strategy implementation and success  Spatial repellency occurs at non-toxic doses and minimal surface area coverage. Chemical gradients over space must be defined to clearly separate SR from Tox  Targeting spatial repellent products at key entry points may increase efficacy. Cost-effective application strategies for development  Defining correlates of vector densities inside a given space with disease transmission must be performed to understand impact factor of a spatial repellent. Evidence of reduced case incidence required to shift a vector control paradigm Summary Statements Uniformed Services University of the Health Sciences

23. Final Words: We Need Additional Tools Uniformed Services University of the Health Sciences

24. Final Words: We Must Consider All Options Uniformed Services University of the Health Sciences Goal is to PREVENT disease transmission – she is one of the fortunate ones. He is one of too many who are not.

25. USUHS Lab Team:  Hortance Manda  Luana Arce  Pankhil Shah  Tarra Tolbert  Cecilia Coscoran  Jennifer Eckhaus Thailand Field Team:  Theeraphap Chareonviriyaphap  Suppaluck Polsomboon  Kranjana Taichum  Sungsit Sungvornyothin  Monthathip Kongmee Peru Field Team:  Kirk Mundal - NMRCD  Fanny Castro - NMRCD  Tom Scott - UCDavis  Amy Morrison - UCDavis  Greg Devine – Rothamsted Research SumbaTeam:  Din Syafruddin – Eijman Insititute  Kevin Baird – Alertasia Foundation  Claus Bogh - Sumba Foundation  Michael Bangs – International SOS  John Grieco -USUHS  Dan Lawson / Maude Meier - SCJ Acknowledgements Uniformed Services University of the Health Sciences Funding supported by grants from: NIH: “Behavior-Modifying Compounds for Disease Control” Bill & Melinda Gates Foundation: “A push-pull strategy for Ae. aegypti Control”

26. THANK YOU FOR YOUR ATTENTION Keep updated: http://www.usuhs.mil/pmb/gsvc