Lyme Disease Information for Clinicians

Though Lyme disease incidence in Illinois is considered low, it does exist and should be considered by clinicians in their differential diagnoses (along with other tick-borne pathogens).

Lyme disease is transmitted to humans from the bite of an infected blacklegged tick (also known as a deer tick).  Borrelia burgdorferi is the primary pathogen causing Lyme disease in Illinois.  A new species of bacteria called Borrelia mayonii, recently found in blacklegged ticks in Illinois, also causes Lyme disease in humans and should be added to testing assays when Lyme disease is suspected.  Both pathogens are transmitted to humans and other mammals by infected blacklegged ticks.

When assessing a patient for Lyme disease, health care providers should consider:

• The signs and symptoms of Lyme disease
• The patient’s Pre-test Probability and Serologic Testing of Lyme Disease
  
• The possibility that other illnesses, including other tickborne pathogens, may cause similar symptoms
  
• Results of laboratory tests, when indicated
  

• Fever
• Fatigue
  
• Headache
  

If a tick-borne disease is suspected, the clinician should collect complete exposure and travel history information from the patient to support their suspicion of Lyme disease or other tickborne illnesses. The clinician should ask the following:

1. Did the patient travel within Illinois, within the United States, or outside the U.S. in the three months prior to symptom onset?
   • If yes, obtain location, departure, and return dates.
     
2. Did the patient enter a tick habitat (wooded or brushy areas with leaf litter or areas with tall grass)?
   
   • If yes, obtain location of tick habitat and dates the patient entered the tick habitat.
     
3. Does the patient have a recent history of a tick bite within the three months prior to symptom onset date?
   
   • If yes, obtain date of tick bite and location of case at time of tick bite.
     

If any of the above questions are answered no, the clinician should also document that in the medical record.

If providers suspect a tickborne illness, they should order a complete tickborne diagnostic panel that includes testing for the following pathogens:

• Anaplasmosis
• Babesiosis
  
• Bourbon virus
  
• Ehrlichiosis
  
• Heartland virus
  
• Lyme disease, including Borrelia burgdorferi and Borrelia mayonii
  
• Powassan virus
  
• Spotted fever group rickettsioses, including Rocky Mountain spotted fever and Rickettsia parkeri
  
• Tularemia
  

Testing for Lyme disease should be done for both Borrelia burgdorferi and Borrelia mayonii as noted above. Serologic assays cleared by the U.S. Food and Drug Administration (FDA) that utilize EIA rather than immunoblot assay in a two-test format are acceptable alternatives for the laboratory diagnosis of Lyme disease. Clinicians and laboratories should consider serologic tests cleared by FDA as Centers for Disease Control and Prevention (CDC)-recommended procedures for Lyme disease serodiagnosis as noted below.

• Modified two-tier test (MTTT) – includes a (tier-1) screening assay, often an enzyme immunoassay [EIA] or immunofluorescence assay [IFA] for immunoglobulin M (IgM), immunoglobulin G (IgG), or a combination of immunoglobulins, followed by a concordant positive IgM or IgG immunoblot (tier-2).
• Nucleic acid amplification test (NAAT) for B. burgdorferi or B. mayonii.
  
• Immunohistochemical assay (IHC) for detection of B. burgdorferi group-specific antigens.
  
• Isolation of B. burgdorferi or B. mayonii in culture.
  
• Standard two-tier test – EIA or IFA antibody screening assay (tier-1) followed by an antibody IgM and IgG immunoblot (tier-2) test.
  

A single dose of doxycycline (200 mg for adults or 4.4 mg/kg for children of any age weighing less than 45 kg) may be used to reduce the risk of acquiring Lyme disease after the bite of a high-risk tick bite when the patient has been in areas that are highly endemic for Lyme disease.

Benefits of prophylaxis may outweigh risks when all the following circumstances are present:

• Doxycycline is not contraindicated
• The attached tick can be identified as an adult or nymphal blacklegged tick
  
• The estimated time of attachment is ≥36
  
• Prophylaxis can be started within 72 hours of tick removal
  
• Lyme disease incidence is high in the state where the tick bite occurred (i.e., Conn., Del., D.C., Mass., Md., Maine, Minn., N.H., N.J., N.Y., Pa., R.I., Va., Vt., Wis., W.Va.)
  

This module highlights the following topics:

• Lyme disease transmission
• Lyme disease geographic distribution
  
• Care of a patient presenting with a tick bite
  
• Appropriate use of post-exposure prophylaxis for Lyme disease following tick bite
  
• Patient education about tick bite prevention
  

This module highlights the following topics:

• Early localized and disseminated manifestations
• Differentiating erythema migrans from other similar skin conditions
  
• Recognizing clinical presentations that might suggest tickborne disease co-infections

This module highlights the following topics:

• How to select validated tests
• Why there is currently no “test of cure”
  
• How pretest probability and disease stage inform whether to test for Lyme disease
  
• The significance of the seroconversion window period
  
• Why testing for Lyme disease may not be clinically helpful for patients with erythema migrans
  

This module highlights the following topics:

• Treatment options for erythema migrans
• Clinical management of Lyme carditis
  
• Clinical management of Lyme arthritis
  
• Clinical management of neurologic Lyme disease
  
• Care of patients with persistent symptoms attributed to Lyme disease