Lyme Disease Epidemiology - Virginia Department of Health

Report
Lyme Disease Epidemiology &
Surveillance in Virginia
David Trump, MD, MPH, MPA
State Epidemiologist
Director, Office of Epidemiology
Virginia Department of Health
History of Lyme Disease
• Illness first described in Lyme, CT in 1975
• By 1977, the Ixodes scapularis (black-legged) tick
was linked with illness transmission
• In 1981, Borrelia burgdoferi was identified as the
causative organism
• In 1984, CT initiated surveillance for Lyme disease
• In 1985, reported incidence of Lyme disease for all
CT residents was 22/100,000
• In 1989, Lyme disease became reportable by
law in VA
• In 1991, Lyme disease became a nationally
notifiable condition in the US
Lyme Disease in the United States
• Most commonly reported vector-borne illness in
the US
• In 2011, 6th most common nationally notifiable
disease
• Does not occur nationwide
• Mostly concentrated in the Northeast and Upper
Midwest
Reported Cases of Lyme Disease in USA
1999
2011
Reported Cases of
Lyme Disease by State
• In 2011, Virginia ranked
10th in the nation for
number of annual cases
reported to CDC
• That same year, Virginia
ranked 14th for
incidence of Lyme
disease
• Pennsylvania currently
reports the most cases
to CDC each year
• Delaware currently
reports the greatest
incidence each year
*Incidence measured by confirmed and
probable cases per 100,000 population
Lyme Disease
Incidence
in Virginia,
2005 in
& Virginia,
2011
2005 & 2012
2012
2005
Cases per 100,000 population
0.1 to 4.9
5 to 9.9
10 to 24.9
25 to 49.9
50 to 99.9
100+
Cases per 100,000 Population
Lyme Disease Incidence in Virginia, 1990-2012
16
14
12
10
8
6
4
2
0
Year
Cases per 100,000 Population
Lyme Disease Incidence by Age Group,
Virginia, 2012
30
25
20
15
10
5
0
Age Group
90
Reported Lyme Disease Cases By Sex and Age,
Virginia, 2012
80
Female [48%]
Male [52%]
Number of Cases
70
Unknown
60
50
40
30
20
10
0
Age Group
Reported Lyme Disease Cases by Month,
Virginia, 2012
180
Number of Cases
160
Cases with Recorded
Onset Dates
140
Cases with Event
Dates Only
120
100
80
60
40
20
0
Month
Understanding Surveillance Data
• Surveillance case definitions establish uniform criteria
for disease reporting
• Data on cases that meet the national surveillance case
definition are shared with CDC
• Case definition should not be used as the sole criteria
for clinical diagnosis
• Policies regarding case definitions, reporting, and data
release are determined by states under the auspices of
the Council of State and Territorial Epidemiologists
(CSTE)
Surveillance Case Definition
Confirmed
A case of erythema migrans (EM) with a known exposure OR
A case of EM with laboratory evidence of infection and without a
known exposure OR
A case with at least one late manifestation that has laboratory
evidence of infection
Probable
Any other case of physician-diagnosed Lyme disease that has
laboratory evidence of infection
Suspected
A case of EM where there is no known exposure and no laboratory
evidence of infection OR
A case with laboratory evidence of infection but no clinical
information available (e.g., laboratory report only).
Surveillance Case Definition
• “Exposure” – Defined as having been (less than or
equal to 30 days before onset of EM) in wooded,
brushy, or grassy areas (i.e., potential tick habitats) in
a county in which Lyme disease is endemic. A history of
tick bite is not required.
• “Endemnicity” – A county in which Lyme disease is
endemic is one in which at least two confirmed cases
have been acquired in the county or in which
established populations of a known tick vector are
infected with B. burgdorferi.
Lyme Disease Endemic Localities in
Virginia for 2013 Surveillance
Two or more Confirmed Cases (2005 – 2012)
Franklin
Brunswick
Galax
Case Definition: “Laboratory Evidence
of Infection”
• Positive Culture for B. burgdorferi, OR
• Two-tier testing - IFA/EIA positive or equivocal plus
IgM Western Blot (WB) positive:
• Positive two tier test is sufficient only when blood
was drawn ≤30 days from symptom onset, OR
• Single-tier IgG WB seropositive (interpreted by
established criteria); sufficient at any point during
illness, OR
• CSF antibody positive for B. burgdorferi by enzyme
immunoassay (EIA) or immunofluorescence assay (IFA),
when the titer is higher than it was in serum
Limitations of Surveillance Data
• Under-reporting and misclassification are features common to all
surveillance systems.
• Not every case of Lyme disease is reported to CDC, and some cases
that are reported may be due to another cause.
• Under-reporting is more likely to occur in highly endemic areas,
whereas over-reporting is more likely to occur in non-endemic
areas.
• Surveillance data is captured by county of residence, not county of
exposure.
• Surveillance data are subject to each state's abilities to capture
and classify cases.
• States may close their annual surveillance dataset at a different
time than CDC. Thus, the final case counts published by CDC may
not exactly match numbers published by each state agency for a
given year.
Reporting
Requirements
• By law, Lyme disease
is a reportable condition
in Virginia
• Report Lyme disease –
when suspected or
confirmed – to your
local health department
within three days
Reporting Requirements
Lyme Disease is a reportable condition in Virginia:
• Code of Virginia 32.1-36 and 32.1-37
• 12-VAC 5-90-80 and 12-VAC 5-90-90 of the
Board of Health Regulations for Disease
Reporting and Control
Local Health Department Directory:
http://www.vdh.virginia.gov/lhd/
§ 54.1-2963.2. Lyme disease testing
information disclosure.
This new law places a requirement on practitioners who
order tests for Lyme disease.
As of July 1, 2013, “every licensee or his in-office
designee who orders a laboratory test for the presence
of Lyme disease shall provide to the patient or his legal
representative” certain information.
§ 54.1-2963.2. Lyme disease testing
information disclosure.
"ACCORDING TO THE CENTERS FOR DISEASE CONTROL AND PREVENTION, AS
OF 2011 LYME DISEASE IS THE SIXTH FASTEST GROWING DISEASE IN THE
UNITED STATES.
YOUR HEALTH CARE PROVIDER HAS ORDERED A LABORATORY TEST FOR THE
PRESENCE OF LYME DISEASE FOR YOU. CURRENT LABORATORY TESTING FOR
LYME DISEASE CAN BE PROBLEMATIC AND STANDARD LABORATORY TESTS
OFTEN RESULT IN FALSE NEGATIVE AND FALSE POSITIVE RESULTS, AND IF
DONE TOO EARLY, YOU MAY NOT HAVE PRODUCED ENOUGH ANTIBODIES TO
BE CONSIDERED POSITIVE BECAUSE YOUR IMMUNE RESPONSE REQUIRES TIME
TO DEVELOP ANTIBODIES. IF YOU ARE TESTED FOR LYME DISEASE, AND THE
RESULTS ARE NEGATIVE, THIS DOES NOT NECESSARILY MEAN YOU DO NOT
HAVE LYME DISEASE. IF YOU CONTINUE TO EXPERIENCE SYMPTOMS, YOU
SHOULD CONTACT YOUR HEALTH CARE PROVIDER AND INQUIRE ABOUT THE
APPROPRIATENESS OF RETESTING OR ADDITIONAL TREATMENT."
Where can I find Lyme disease
statistics?
• CDC Webpage: http://www.cdc.gov/lyme/
• VDH Reportable Disease Surveillance Data
http://www.vdh.virginia.gov/Epidemiology/Surveillanc
e/SurveillanceData/
• Morbidity and Mortality Weekly Report (MMWR)
http://www.cdc.gov/mmwr/mmwr_wk/wk_cvol.html
Role of Public Health: Prevention and
Control
VDH
CDC
• Contribute to the
understanding of Lyme disease
• Education of public and
providers
• Conduct surveillance for Lyme
disease in Virginia
• Emphasis on prevention
• Primary prevention
• Secondary prevention
• Maintaining and analyzing
national surveillance data for
Lyme disease
• Conducting epidemiologic
studies
• Offering diagnostic and
reference laboratory services
• Developing/testing strategies
for the control and prevention
Lyme disease in humans
• Supporting education of the
public and health care
providers
Thank You!

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