Lyme Disease

Life Cycle of the Ixodes scapularis Tick

  • Winter:
    • Ticks remain dormant.
    • Eggs deposited in spring.
  • Spring:
    • Nymph Stage:
    • Duration: 1 month.
    • Feeds once, usually on deer (preferred host).
  • Summer:
    • Larvae Stage:
    • Feeds once for approximately 2 days on mice (preferred host).
  • Fall:
    • Adults die after feeding once for 3-4 days on mice.

Lyme Disease - Definition

  • Definition:
    • Lyme Disease is a multi-system illness affecting the skin, central nervous system (CNS), heart, and joints.
    • Causative Agent:
    • The disease is caused by a spirochete, specifically Borrelia burgdorferi.

Lyme Disease - History

  • History:
    • 1969: First reported case involving a Wisconsin physician bitten by a tick.
    • Patient developed an annular rash known as erythema chronicum migrans (ECM).
    • 1975:
    • Reports of 4 cases of ECM rash from a US Navy base in Groton, Connecticut.
    • Further 4 cases reported by a physician in Lyme, Connecticut.
    • 1983:
    • William Burgdorfer and Barbour isolate the previously unrecognized spirochete, naming it Borrelia burgdorferi.
    • 1986:
    • First case reported in Georgia.
    • 2017:
    • Over 300,000 infections reported in the USA, note: the number is likely growing and underreported.

Lyme Disease - Vaccine

  • Current Status of Vaccine Development:
    • A vaccine for Lyme disease is currently not available.
    • The previously used vaccine Lymerix was discontinued due to insufficient consumer demand.
    • Companies Pfizer and Valneva have initiated Phase 3 of their Lyme disease vaccine development.
    • A vaccine for dogs is already available.

Spirochetes - Description

  • Definition:
    • Spirochetes are small, microscopic, obligate intracellular microorganisms.
    • They are considered prokaryotic eubacteria.
    • Characteristics:
    • Possess a cell wall and are gram-negative.
    • Motility: exhibit corkscrew movement.
    • Shape: long, slender, and spiral-shaped.
    • Categories of Spirochetes:
    • Treponema: Causes syphilis.
    • Borrelia: Includes Borrelia burgdorferi responsible for Lyme disease.
    • Leptospira: Causes leptospirosis.

Lyme Disease - Borrelia

  • Description:
    • Borrelia is a spirochete with a long, slender, helical shape.
    • Characteristics:
    • Exhibits 4 to 10 loose, irregular coils and corkscrew-like motility.
    • Microaerophilic, requiring low oxygen levels for survival.
    • Method of visualization: Dark field examination of Borrelia burgdorferi.

Tick-Borne Diseases

  • Overview:
    • Tick-borne diseases are the most common tick-borne illness in the United States.
    • Transmission:
    • Typically transmitted by Ixodes ticks.
    • Hosts include the white-tailed deer and the white-footed mouse.

Lyme Disease - Epidemiology

  • Epidemiology:
    • Peak infection periods are usually in early summer when ticks are developing.
    • During the nymphal stage, ticks are approximately the size of a pinhead.
    • Transmission of the disease requires ticks to remain attached for at least 24 hours for effective transmission.

Lyme Disease - Occurrence

  • Key Statistics:
    • Predominantly affects the northeastern United States, with 92% of all cases arising from 8 states:
    • New York, New Jersey, Pennsylvania, Connecticut, Massachusetts, Rhode Island, Wisconsin, and Minnesota.
    • Disease distribution is reported to the CDC by county of residence, and data must be interpreted considering where the disease was diagnosed versus where it was acquired.

Lyme Disease - Symptoms

  • Common Symptoms:
    • Erythema migrans lesion at the tick bite site, resembling a bullseye rash.
    • Flu-like symptoms including fatigue, fever, headaches, and muscle pain.
    • Joint pain that is frequently misdiagnosed as arthritis.
    • Involvement of the CNS and the heart if untreated.

Lyme Disease - Stage 1

  • Stage 1 Characteristics:
    • Red, annular skin lesion appearing at the site of the tick bite, spreading outward from the center, resembling a bullseye.
    • Onset of flu-like symptoms can occur about 2 days to 2 weeks after the tick bite.

Lyme Disease - Stage 2 & 3

  • Stage 2:
    • Occurs within weeks to months after the initial infection.
    • The spirochete can cross the blood-brain barrier, affecting the CNS and heart. Symptoms in this stage are not permanent.
  • Stage 3:
    • Chronic arthritis may develop, persisting for years after the initial infection.

Antibody Production - Stage 1

  • Initial Antibody Response:
    • Lag Phase: Initial 2-4 weeks show no antibody (Ab) production.
    • Measurement of antibodies begins after symptoms appear. The primary antibody in stage 1 is IgM (immunoglobulin M).
    • IgM levels rise slowly, peaking 3-6 weeks post-infection.

Antibody Production - Stage 2 & 3

  • Subsequent Antibody Response:
    • In stages 2 and 3, IgG (immunoglobulin G) is the second antibody produced, peaking months after the initial infection and may persist for years.
    • IgA: Predominantly found in cerebrospinal fluid (CSF) and joint fluid.

Lyme Disease - Diagnosis

  • Diagnosis Methodology:
    • A combination of polyclonal antibody assays is used.
    • Tests detect both IgM for Stage 1 and IgG for Stages 2 and 3 against Borrelia burgdorferi.

Lyme Disease - Tests

  • Tests Available:
    • Passive Agglutination: Screening test (not confirmatory).
    • Immunofluorescence (IFA): Also detects antibodies.
    • Enzyme Linked Immunosorbent Assay (ELISA): Commonly used for screening.
    • Western Blot: Confirmatory test.
    • PCR (Polymerase Chain Reaction): Detects Borrelia DNA.

Two-Tiered Testing for Lyme Disease

  • Testing Protocol:
    1. First Test: Enzyme Immunoassay (EIA).
      • Positive signs or symptoms present for ≤ 30 days: proceed to IgM and IgG Western Blot.
      • If the result is equivocal or negative with signs/symptoms > 30 days, proceed with IgG Western Blot only or consider alternative diagnoses.

Lyme Disease - Slide Test

  • Latex Agglutination Slide Test:
    • Principle: Passive agglutination.
    • Reagent: Latex particles coated with Borrelia antigen.
    • Note: This test is no longer performed; ELISA or IFA methods are preferred for higher sensitivity and specificity.

Lyme Disease - Indirect Immunofluorescence Assay (IFA)

  • IFA Principle:
    • Indirect immunofluorescence method for detecting either IgM or IgG anti-Borrelia antibodies.
    • Reagent: Borrelia antigen attached to slides or wells, reacted with fluorescent goat anti-human IgG.

Lyme Disease - IFA Interpretation

  • Interpretation Guidelines:
    • Report based on the highest dilution showing immunofluorescence.
    • Positive Result: Immunofluorescence titer of 1:80 or greater.
    • Negative Result: No immunofluorescence or titer < 1:40.
    • Borderline Result: Titer of 1:40.

Lyme Disease - IFA Results

  • Explanation:
    • A titer of 1:40 indicates confirmation required for diagnosis.
    • Cross-reactivity with other Borrelia and possible spirochetes can occur.

Lyme Disease - ELISA - Principle

  • ELISA Methodology:
    • Principle: Enzyme Immunoassay, sandwich technique.
    • Reagents Used:
    • Borrelia burgdorferi antigen, enzyme-tagged goat anti-human IgG, and substrate/color developer.

Lyme Disease - ELISA - Prestep

  • Preliminary Steps in ELISA Testing:
    • Dilute patient serum in adsorbent liquid to remove interfering substances.
    • Prepare microtiter plate coated with Borrelia burgdorferi antigen for testing IgM and IgG of Lyme disease.

Lyme Disease - ELISA Procedure

  • Detailed ELISA Procedure:
    1. Add diluted patient serum to wells.
    2. Incubate and wash.
    3. Add enzyme-labeled goat anti-human IgG.
    4. Incubate and wash again.
    5. Add substrate/color developer and observe for color change as an indication of a positive result.

Lyme Disease - ELISA - Interpretation

  • Guidelines for Interpretation:
    • Positive Result: Indicated by color change.
    • Negative Result: No color change.
    • Report the highest dilution (titer) showing color change; a fourfold increase in IgG titer between acute and convalescent samples confirms diagnosis.

Western Blot Interpretation

  • Interpretation Notes for Western Blot Testing:
    • Used as a confirmation test if prior ELISA results were positive or inconclusive.
    • For IgM testing: If symptoms have persisted for less than 4 weeks, look for bands p23, p39, p41.
    • For IgG testing: If over 6 weeks, look for bands p18, p23, p28, p30, p39, p41, p45, p58, p66, and p93.
    • At least 2 positive bands are required for a positive interpretation in IgM and any 5 positive bands for IgG; bands 23, 31, 34, 39, 83/93 are specific to Lyme Disease.

Western Blot Procedure

  • Detailed Process:
    • ELISA Phase: Solid phase antigen produced using SDS-PAGE and transferred to nitrocellulose paper.
    • Western Blot Phase:
    1. Add patient serum for incubation.
    2. Add enzyme-labeled anti-human IgG for further incubation.
    3. Add substrate/color developer to visualize antigens.

Lyme Disease - PCR

  • PCR Testing Information:
    • PCR (polymerase chain reaction) test amplifies the DNA of Borrelia spirochete, enhancing detection of small amounts.
    • Particularly useful in evaluating individuals with chronic Lyme disease or arthritis and testing CSF from those with neurological symptoms.
    • Note: PCR tests can yield false negatives due to low numbers of Borrelia in sampled tissue.

Sources of Error - False Positive

  • Potential Causes of False Positive Results:
    • Cross-reactions with other spirochetes, such as those causing syphilis.
    • Cross-reaction with other Borrelia species (e.g., Borrelia hermsii).
    • Autoimmune diseases such as rheumatoid arthritis.

Sources of Error - False Negative

  • Potential Causes of False Negative Results:
    • Testing too early, especially within three weeks post-infection due to insufficient antibody production.
    • Low levels of Borrelia in the sample (PCR context only).
    • 15% of patients do not produce antibodies.
    • Previous antibiotic treatment can suppress antibody production.

Lyme Disease - Quick Facts

  • General Information:
    • Lyme disease can solely be transmitted by ticks, not by mosquitoes, biting flies, or spiders.
    • The disease often evades detection and can mimic other conditions, such as arthritis.
    • Only about 25% develop the characteristic bullseye rash; many may not develop any rash at all.
    • Lyme disease can be transmitted in less than 24 hours from an infected tick.
    • It may manifest as a co-infection with other pathogens.
    • Symptoms may appear as early as 2 days or take weeks to emerge.
    • Human-to-human transmission is limited to transplacental (congenital) transmission.
    • Lyme disease can affect every organ system, often leading to misdiagnosis.
    • Antibiotics usually cure early-stage infections.
    • Antibodies begin to appear approximately four weeks after symptoms arise.

Lyme Disease Videos

  • Educational Videos Available:
    • YouTube Links:
    • www.youtube.com/watch?v=xxxxx: Lyme Disease by teamrivas
    • www.youtube.com/watch?v=yyyyy: Lyme Disease & Possible Babesia by cdntnkrbell