Lyme Disease Epidemiology & Surveillance in Virginia

David Trump, MD, MPH, MPAState Epidemiologist

Director, Office of EpidemiologyVirginia 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

2005

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

in Virginia, 2005 & 2011 Lyme Disease Incidence in Virginia, 2005 & 2012

2012

19901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012

0

2

4

6

8

10

12

14

16

Year

Case

s pe

r 100

,000

Pop

ulati

on

Lyme Disease Incidence in Virginia, 1990-2012

Und

er 5

5 - 9

10 -

1415

- 19

20 -

2425

- 29

30 -

3435

- 39

40 -

4445

- 49

50 -

5455

- 59

60 -

6465

- 69

70 -

7475

- 79

80 -

84 85+

Tota

l

0

5

10

15

20

25

30

Age Group

Case

s pe

r 100

,000

Pop

ulati

onLyme Disease Incidence by Age Group, Virginia,

2012

Under

5 5-9

10-1

415

-19

20-2

425

-29

30-3

435

-39

40-4

445

-49

50-5

455

-59

60-6

465

-69

70-7

475

-79

80-8

485

+

0

10

20

30

40

50

60

70

80

90

Reported Lyme Disease Cases By Sex and Age, Virginia, 2012

Female [48%]Male [52%]Unknown

Age Group

Num

ber o

f Cas

es

Jan.

Feb.

Mar

.

Apr.

May Jun. Jul.

Aug.

Sep.

Oct.

Nov.

Dec.

0

20

40

60

80

100

120

140

160

180

Reported Lyme Disease Cases by Month, Virginia, 2012

Cases with Recorded Onset Dates

Cases with Event Dates Only

Month

Num

ber o

f Cas

es

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 DefinitionConfirmedA case of erythema migrans (EM) with a known exposure ORA case of EM with laboratory evidence of infection and without

a known exposure ORA case with at least one late manifestation that has laboratory

evidence of infectionProbableAny other case of physician-diagnosed Lyme disease that has

laboratory evidence of infectionSuspectedA case of EM where there is no known exposure and no

laboratory evidence of infection ORA 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

Franklin

Brunswick

New Kent

Gloucester

Galax

Two or more Confirmed Cases (2005 – 2012)

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/Surveillance/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• 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

CDC• 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!