LYME DISEASE

Wisconsin Division of Public Health Disease Surveillance Manual (EpiNet, August 2008)

I.       IDENTIFICATION

A.        CLINICAL DESCRIPTION: A multi-systemic disease caused by a spirochete Borrelia burgdorferi that is transmitted through the bite of infected deer ticks (Ixodes scapularis) in Wisconsin. Within 3-30 days of the bite, 70-80% of those infected exhibit a distinctive rash called erythma migrans (EM) that expands in size over a period of days or weeks (see description in Definitions and Clarifications below).  However, about 25% of the patients do not have the EM rash or the lesions are unnoticed by the patients. The expansion of the EM rash helps to differentiate from an allergic reaction at the site of the bite; unlike the EM rash the allergic reaction does not expand and disappears within a few days. EM is often accompanied by malaise, fatigue, headache, fever, chills, and swollen lymph nodes. After several weeks to months, untreated patients may develop facial palsy, severe headaches, neck stiffness, migratory pain in joints, tendons, muscles or bones, neurologic abnormalities, or cardiac disturbances. After several months to years, approximately 60% of untreated patients may develop intermittent bouts of arthritis including pain and swelling in large joints, about 15% may develop neurological symptoms, and 5% may have cardiac manifestations (see Late Manifestations below).

B.        REPORTING CRITERIA: Clinical diagnosis.

1. Laboratories must report all positive test results.
2. All confirmed, probable, and suspect cases should be reported to the Division of  Public Health (DPH).  Cases that are classified as “not a case” do not need to be reported.

C.        LABORATORY CRITERIA FOR CONFIRMATION: For the purpose of surveillance, the definition of a qualified laboratory assay is (1) a positive culture for B. burgdorferi, (2) two-tier testing* with IgM immunoblot seropositive result for specimens collected within 30 days of onset date, or (3) positive IgG immunoblot interpreted using established criteria. Additional assays including PCR will be considered on a case by case basis.
                * Two-tier testing includes an initial screen by enzyme immunoassay (EIA) or indirect immunofluorescence assay (IFA), followed by a Western immunoblot on any equivocal or positive EIA or IFA results.

D.        WISCONSIN CASE DEFINITION: Based on the revised national case definition
            effective January 1, 2008.
               
Confirmed case:

• Erythema Migrans (EM) in a Wisconsin resident.  (Note that although the national case definition requires a known “exposure” as defined below, DPH considers the entire state of Wisconsin to be endemic. Thus any Wisconsin resident is considered “exposed”.)

or

• At least one late manifestation (described below) and laboratory evidence of infection that meets criteria listed in section “C” above.

Probable case:

• Any other physician-diagnosed Lyme disease with laboratory evidence of infection that meets criteria listed in section “C” above, with only non-confirmatory signs and symptoms (see description below).

Suspect case:

• At least one late manifestation but only has a positive IgG EIA/IFA result or only has a total antibody result (i.e. IgM or IgG was not specified)

            or

• Any positive laboratory test with no clinical information available (e.g. a laboratory report without a case report form).

           
 Not a Case:

•  Any case report that does not meet the confirmed, probable, or suspect category.

 
Definitions and Clarifications:

Erythema migrans (EM). For the purposes of surveillance, EM is defined as a skin lesion that typically begins as a red macule or papule and expands over a period of days to weeks to form a large round lesion, often with partial central clearing creating a “bull’s-eye” appearance. To meet the case definition a single primary lesion must reach greater than or equal to 5 cm in size. Secondary lesions may also occur. A hallmark of EM is its gradual expansion over several days. Annular erythematous lesions occurring within several hours of a tick bite represent hypersensitivity reactions and do not qualify as EM. For most patients, the expanding EM lesion is accompanied by other acute symptoms, particularly fatigue, fever, headache, mildly stiff neck, arthralgia, or myalgia. These symptoms are typically intermittent. The diagnosis of EM must be made by a physician.  Laboratory confirmation is recommended for persons with no known exposure.
Confirmatory late manifestations. Late manifestations include any of the following when an alternate explanation is not found:

• Musculoskeletal system. Recurrent, intermittent attacks (weeks or months) of objective joint swelling in one or a few joints, sometimes followed by chronic arthritis in one or a few joints. Manifestations not considered as criteria for diagnosis include chronic progressive arthritis not preceded by brief attacks and chronic symmetrical polyarthritis. Additionally, arthralgia, myalgia, or fibromyalgia syndromes alone are not criteria for musculoskeletal involvement.
  
  
• Nervous system. Any of the following, alone or in combination: lymphocytic meningitis; cranial neuritis, particularly facial palsy (may be bilateral); radiculoneuropathy; or, rarely, encephalomyelitis. Encephalomyelitis must be confirmed by demonstration of antibody production against B. burgdorferi in the CSF, evidenced by a higher titer of antibody in CSF than in serum. Headache, fatigue, paresthesia, or mildly stiff neck alone are not criteria for neurologic involvement. 
  
  
• Cardiovascular system. Acute onset of high-grade (2nd-degree or 3rd-degree) atrioventricular conduction defects that resolve in days to weeks and are sometimes associated with myocarditis. Palpitations, bradycardia, bundle branch block, or myocarditis alone are not criteria for cardiovascular involvement.

Non-confirmatory.  Non-confirmatory signs and symptoms include:
Fever, sweats, chills, fatigue, neck pain, arthalgias, myalgias, fibromyalgia syndromes, cognitive impairment, headache, paresthesias, visual/auditory impairment, peripheral neuropathy, encephalopathy, palpitations, bradycardia, bundle branch block, myocarditis, or other rash.

Exposure. Exposure is 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. To simplify Lyme disease surveillance, DPH considers all Wisconsin residents exposed. 

Endemic county.  A county in which at least two confirmed cases have been acquired or in which established populations of a known tick vector are infected with B. burgdorferi.  For the purpose of surveillance, DPH considers all Wisconsin counties to be endemic.

 

II.       ACTIONS REQUIRED / PREVENTION MEASURES

A.        WISCONSIN DISEASE SURVEILLANCE CATEGORY II: Report to the patient's local health officer on an Acute and Communicable Disease Case Report (DPH 4151) or other means within 72 hours of the identification of a case or suspected case.

B.        EPIDEMIOLOGY REPORTS REQUESTED:

1. Acute and Communicable Diseases Case Report is available: DPH 4151. 
2. Wisconsin Lyme Disease Case Report Form revised 07/18/08 is available:  CDES #107- rev0708.

C.        PUBLIC HEALTH INTERVENTIONS / FOLLOW-UP:

• Completion of the Wisconsin Lyme Case Report Form (CDES #107- rev0708) on all DPH 4151 and positive laboratory reports to ascertain case status and to determine county of probable exposure.
• Patient education as needed to minimize future tick exposure.
• Laboratory results received by DPH will be sent to the LHD where patients reside whenever jurisdiction information is available.

III.       CONTACTS FOR CONSULTATION

A.        BCD / COMMUNICABLE DISEASE EPIDEMIOLOGY SECTION:
            Vector-borne Epidemiologist at 608-267-9000

B.        REGIONAL STAFF: See EpiNet Introduction: “REGIONAL OFFICE  CONTACTS”.

C.        BACTERIAL SEROLOGY: Wisconsin State Laboratory of Hygiene (WSLH) at (608) 262-3217 performs Western Immunoblot (IgM and IgG ) testing on serum specimens. Other tests may be forwarded to CDC as appropriate.

D.      TICK IDENTIFICATION:  The public can send in ticks for identification at no charge through the University of Wisconsin, Department of Entomology.  Please contact DPH for further information.

IV.       RELATED REFERENCES

 Link to websites:

1. “Lyme Disease” DPH Disease Fact Sheet Series, (Rev. 12/03): 
   http://dhfs.wisconsin.gov/communicable/FactSheets/LymeDisease.htm
   Lyme disease surveillance:
   http://dhfs.wisconsin.gov/communicable/LymeDisease/index.htm   
   http://www.cdc.gov/ncidod/dvbid/lyme/index.htm
   http://www.cdc.gov/ncphi/disss/nndss/casedef/case_definitions.htm
   • Heymann DL, ed. LYME DISESE. Control of Communicable Diseases Manual. 18th ed. Washington, DC: American Public Health Association, 2004:315-320.
     
     
   • “Lyme Disease” - CDC brochure with “Wisconsin Supplement to CDC Lyme Disease Brochure”; POH 9287 and 9287A respectively.
     
     
   • “Lyme Disease: Guidelines for Wisconsin Health Care Providers” Wisconsin Division of Public Health. March 1999; PPH 42000.