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Lyme3802019.pptxLyme disease: ecology and emergence
Context
1975: a resident of Old Lyme, CT reported to the State Health Dept that there were 12 children in the town with Juvenile Rheumatoid Arthritis
Rheumatology Clinic@ Yale is notified of an “epidemic” of JRA in family, community
Surveillance system set up-
39 children, 12 adults identified with a “rash” of sxs
17/39 children lived on one road
10% of the children in a slightly wider area had symptoms
Symptoms
Swelling in knee or other large joint x 1 wk
Recurrence frequent
50%: reported nonspecific syndrome
Fever
Muscle aches (myalgias)
Joint pain generally (arthralgias)
Headache, chills, malaise
Many noted a “circular” rash about 1 month before the symptoms
Context
Similar syndrome known to be in Europe—
Erythema migrans (“moving redness”)
Caused by bite from a tick
Ixodes ricinus—”sheep tick”
Not associated with arthritis
Controversy of “chronic Lyme”
Back to the US
Surveillance around Lyme CT
Introductory lectures to population, providers
People then went to clinics, providers
“passive surveillance” vs. “active surveillance”
Incidence on one side of river: 2.8/1000
Incidence on other: 0.1/1000
Some remembered tick bite
(cont)
Tick-the “deer tick” or Ixodes scapularis (conflict about whether it was called I. dammini)
Many ticks on high prevalence side of river
Few ticks on low prevalence side
Entomologic survey:
Many ticks on Peromyscus leucopis (white footed mouse)
Many mature ticks on white tailed deer
Original Description of Lyme Disease
Arthritis and Rheumatism 1977;20:7
Long search for pathogen
Many techniques used w/o results
Willy Burgdorfer, Yale—medical entomologist
Specialty: ticks
Noted bacteria in ticks
Assoc. with immune response in those with Lyme Disease
Similar to samples from Europe, late 1940s
Same bacterium found in patients: Borrelia burgdorferi—gram negative spirochetes
Did the pathogen get imported to N. America, or was it there for thousands of years? How was it imported?
First Description: Mice are Crucial
Am J Trop Med Hyg, 1985;34:355-360
Source: Steere et al, The emergence of Lyme Disease, Journal of Clinical Investigation
2004; 113:1093-1101
Source: CDC
Source: CDC
LYME DISEASE 2017
SOURCE: Kugster et al, Emerg Inf Dis, 2015
http://www.aldf.com/usmap.shtml
CONCEPTS, LYME DISEASE RISK MAP
Source: WALLER, L.
LYME HABITAT SUITABILITY--
Environ Health Perspect 111:1152–1157 (2003).
Fragmentation of land
Several studies confirm
Land fragmentation conducive to Lyme disease existence
More fragmentation—more Lyme
What might have happened to explain Lyme?
Components in understanding
Land
Population
Agriculture
Economy
Zoogeography
Entomology
And lots of other things
Emergence: IOM-1
Steps in Distribution of Lyme disease
Need to understand historical geography of US and Canada
European arrival
Amerindians and Europeans both cleared land
Agriculture and settlement
Industrialization and urbanization
Concentration of more population in urban areas, E. seaboard
Required agriculture from periphery
Land clearance
Forced deer north, and into more rural areas
DEER ARE “EDGE DWELLERS”-interface of forest, non-forest
Next
Increases in population
More urbanization
Commercial agriculture
Agriculture moved to the north and west
Pushed deer further north
Then…..
Construction of railroads
Allows suburbanization
Land value high in center-supply and demand
Social values: people crave larger and larger
homes
Suburbs in proximity to
Second growth forest
Deer move to south to major population centers, forests
People live very very close to deer-same land
CREATES CONDITIONS FOR LYME
INTERSTATE HIGHWAY SYSTEM
Begun mid 50’s
More or less complete by 1970
Many videos, descriptions of “chronic Lyme”
Certainly a syndrome after Lyme disease is well described
Politicized issue: does “chronic Lyme” exist? EXAMPLE
