1. People andForest Patches: Residential exposure and Lyme disease in Southern New England Senior Thesis in Environmental Science Allan Just April 19 th , 2005 Source: Sarah Leen

2. People, Environment, and Lyme Disease 3. Study Questions

How does human interaction with tick habitats influence the public health risk of Lyme disease?

• What are the spatial patterns of disease?

• What is the role of potential habitat and residential exposure?

4. Outline

Study Question

Public Health and Environmental Integrity

Lyme Disease Introduction

• Ecology of Lyme Disease

• Human Exposure and Risk

Study Design

• Data Sources

• Variable construction and analysis

Results

• Visualizing the human risk of Lyme disease

• The importance of residential exposure

Implications and Future Directions

5. Ecology of Lyme Disease

Agent

Borrelia burgdorferi

• Spirochete

Vector

Ixodes Scapularis

• Deer Tick

Host

Reservoir

Source: Centers for Disease Control 6. Bloodmeals Source: American Lyme Disease Foundation 7. Lyme Disease Burden

23,763 cases of Lyme disease nationally in 2002

Pathology

Acute - bulls eye rash

Chronic Joint inflammation

Neurological symptoms

Rare - Cardiac symptoms

Source: CDC Lyme DiseaseMMWR Jan 18, 2002/51(02) 8. Tick Habitat Characteristics

Eco Approach

• Focused on Ecology and Entomology

• Usually limited to small areas and short sampling season

• Often focus on entomologic indices of human risk

• ?

9. Tick Habitat Characteristics

Eco Approach

• Focused on Ecology and Entomology

• Usually limited to small areas and short sampling season

• Often focus on entomologic indices of human risk

Characteristics of where ticks are found

• Deciduous Forest

• Nearby Ornamentals and Lawns

• Smaller Patches?

• Sandy Soils?

• Near Water?

10. Human Exposure

Public Health Approach

• studies focus on individual human behaviors and nearby habitat

• Case-control designs are limited in area and numbers

Exposure characterized in the northeast as Peridomestic

Distance from residence to forest is important

Also recreational and occupational exposures beyond the home

11. Outline

Study Question

Public Health and Environmental Integrity

Lyme Disease Introduction

• Ecology of Lyme Disease

• Human Exposure and Risk

Study Design

• Data Sources

• Variable construction and analysis

Results

• Visualizing the human risk of Lyme disease

• The importance of residential exposure

Implications and Future Directions

12. Study Area and Population

Southern New England

• Connecticut

• Rhode Island

• Massachusetts

All residents from 1998-2002

• 559 Cities and Towns

13. Data Sources

Lyme Disease Cases

• MA Department of Public Health

• RI Department of Health

• CT Department of Public Health

Nationally Notifiable Disease since 1991

Uniform Case Definition

The author is not affiliated with the Massachusetts Department of Public Health and the Department of Public Health is not responsible for the accuracy and validity of the results presented.The views stated are not necessarily those of the Department. 14. Data Sources

Land Cover

• National Land Cover Dataset 1992

• 30 x 30 meter pixel size

Demographics

• US Census 2000

• Block level smallest spatial unit; Average 73 persons

15. Variable Construction

Multi-state GIS, Raster Overlay

An Example Urban-to-Rural transect of Towns in Rhode Island

Land Cover Census Population Density 16. Zooming in 17. RuralUrban Population Density 18. Land Cover 19. 67%55%43%3% Increasing Proportion of town area classified as deciduous forest 20. Increasing Proportion of the Population at 30m or less from deciduous forest 85%74%37%2% 21. Results

Visualizing Lyme Disease Cumulative Incidence

Association with Deciduous Forest

Residential Exposure Aggregates

22. 23. Deciduous Forest and Cumulative Incidence of Lyme disease Relative Rate =13(10 to 16) Rate of 50 Lowest towns Rate of 27 Highest Towns 24. Residential Exposure Aggregates and Cumulative Incidence of Lyme disease Relative Rate =26(20 to 34) Rate of 47 Lowest towns Rate of 14 Highest Towns 25. can we simply pave over the ticks 26. can we simply pave over the ticks 27. can we simply pave over the ticks 28. can we simply pave over the ticks 29. 30. Comparison 31. Comparison 32. Comparison 33. Further Steps

Multivariate Modeling that accounts for rare disease outcome

Stratify by Ecoregions to observe variation that may be abiotic

Interpret more recent remotely sensed images for land cover, likely habitat, and the role of mixed pixels

34. Benefits and Policy Implications

Regional scale for decision making and prioritization

Applicable to future endemic areas for prediction

Promote compact development in town planning and at the state/regional level

Add loss of health from disease to costs of sprawl

35. Acknowledgments Rachel Morello-Frosch Jen Hughes, Sally Zierler, John Brownstein Bill Jesdale Lynn CarlsonTracy LaPorte, Dr. Bandy Catherine Starr The Suite Noam Ross Friends and Family The ES Community 36. 37.