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Lyme Disease

Image : “OSC Microbio 12 02 LymeRash” by CNX OpenStax. License: CC BY-SA 4.0


Definition of Lyme Disease

Adult deer tick, Ixodes scapularis.”

Lyme disease is caused by an infection by bacteria of the species Borrelia burgdorferi, Borrelia mayonii, Borrelia afzelli, and Borrelia garinii. These belong to the family of gram-negative spirochetes. The agents are transmitted to humans via bites of infected black-legged ticks known as deer ticks. The ticks are more common in grassy and woody areas. The disease manifests itself in different organs; most commonly affected are the skin, the neuro system, and the joints.

Synonyms: Lyme-Borreliosis, Neuroborreliosis, Lyme disease.

Lyme-Borreliosis is named after the village Lyme (Connecticut, USA). It was in this village, where joint inflammation occurred frequently. Wilhelm Burgdorfer discovered the bacteria in 1981, but the skin manifestations had already been described in Europe.  

Epidemiology of Lyme Disease

Prevalence of Lyme-Borreliosis

By Vice regent at en.wikipedia – Vice regent (talk) (Uploads). Transferred from en.wikipedia by SreeBot, GFDL, Link

Lyme-Borreliosis represents the most frequently transmitted disease via ticks in Europe.

  • 5–35% of the ticks are infected with Borrelia.
  • The infection can occur from March to October; the critical period is from June to July.
  • The regional spread of the infected ticks applies differently in various locations and should be considered for the diagnosis.

Etiology and Pathogenesis of Lyme Disease

Agents of Lyme-Borreliosis

Lyme-Borreliosis is caused by different species of borrelia, that all belong to the complex Borrelia burdoferei sensu lato. The following 4 human-pathogenic species are most often represented:

  • Image: “Using darkfield microscopy technique, this photomicrograph, magnified 400x, reveals the presence of spirochete, or “corkscrew-shaped” bacteria known as Borrelia burgdorferi, which is the pathogen responsible for causing Lyme disease. Borrelia burgdorferi are helical shaped bacteria, and are about 10 – 25µm long. These bacteria are transmitted to humans by the bite of an infected deer tick, and caused more than 23,000 cases of Lyme disease in the United States during 2002.” by Centers for Disease Control and Prevention’s Public Health Image Library (PHIL). License: Public Domain.

    Borrelia burgdorferi sensu stricto

  • Borrelia garinii
  • Borrelia garinii
  • Borrelia afzelii
  • Borrelia spielmanii

Reservoir of the Borrelia

  • Small rodents and birds
  • Deer and roes are animal hosts for ticks
  • A couple hundred vertebrate species are potential hosts for the hard ticks

Path of infection and pathogenesis of the Lyme Borreliosis

Image: “The black-legged tick (Ixodes scapularis), the primary vector for Lyme disease in the central and eastern United States (and elsewhere too. Uploader).” by A New View on Lyme Disease: Rodents Hold the Key to Annual Risk. Gross L, PLoS Biology Vol. 4/6/2006, e182. License: CC BY 2.5

In Central Europe, borrelia bacteria are transmitted via the bite of the hard tick Lxodes (I.) ricinus and Lxodes scapularis. The ticks can move from low vegetation (1.5 m) to humans.

Note: With the attachment period, the risk of disease increases significantly. The attachment period is dangerous from 24 hours on. Certain surface proteins of the Borrelia bacteria ensure that they can attach to the host cells. Pro-inflammatory cytokines are released during the attachment period.

More different immune mechanisms are discussed:

  • Induction of autoantibodies against neuronal and glial antigens
  • Cross-reactivity of Borrelia antibodies with neuronal antigens.
  • T-cell-mediated immune response.

Borrelia bacteria can survive for many years in the host, for example, in phagocytes.

Risk groups: are forestry workers, hunters, farmers, and hikers.

Incubation period: 4–18 days

Symptoms of Lyme Disease

Staging for Borreliosis

There are three stages to the symptomatology of a Borreliosis:

Stage I Week 1 – 5

Incubation period:  Weeks to months

Erythema migrans - erythematous rash in Lyme

Erythema migrans – erythematous rash in Lyme

Erythema chronicum migrans is a bull’s eye rash that appears about 2 weeks after a tick bite. This skin reaction corresponds to the local spread of the bacteria in the dermis. Just half of the patients, that are experiencing stage 1, have Erythema chronicum migrans. Symptoms, such as fever, myalgia, arthralgia, and weariness can occur. Typically, the patients without those symptoms have issues in the respiratory tract (flu without a cough, sputum or rhinitis).

Note: Erythema chronicum migrans may not occur!

Stage II

Incubation period: Weeks to months

Meningoradiculitis or Bannwarth-syndrome can include radicular pains, partly radicular paresis, peripheral facial palsy (often on both sides). Symptoms can include joint involvement, myocarditis, pericarditis or Lympadenosis cutis benigna. The latter describes reactive hyperplasia of the lymphatic cells. The Lymphadenosis cutis benigna manifests itself mainly in terms of bluish-red nodes in the skin, for example, near the earlobe.

Stage III

Incubation period: Months to years

The patients can suffer from Acrodermatitis chronica atrophicans herxheimer. This dermatologic manifestation of the Borreliosis has chronic-progressive stages; the extensor sides of the extremities are the most affected. At first, there is edema. Next, atrophy of the subcutis develops resulting in the subcutaneous fat whereby the thickness of the skin becomes reduced and the vessels beneath the skin can shine through. Finally, the affected parts of the skin become sclerotic and develop a significant thickening that is hairless. Other symptoms include Lyme arthritis with a 90% manifestation in the knee joint. There is also a possibility of eye involovment with uveitis, keratitis, episcleritis, and retinal vasculitis.

The symptoms appearing in the stage 3 of a chronic neuroborreliosis are:

  • Encephalomyelitis: Paraparesis and tetraparesis
  • Distal-symmetric Polyneuropathy
  • Ataxia
  • Bladder dysfunction
  • Dysesthesias and asymmetric radicular signs of paralysis
  • Heart problems such as irregular heartbeats
  • Hepatitis
  • Severe fatigue
Note: The staging for Borreliosis should be considered as a theoretical construct, as it is too artificial.

For the clinical classification, the categorization is considered in an early and late manifestation of the disease:

  • Early manifestation (Erythema migrans, acute neuroborreliosis)
  • Late manifestation (arthritis, acrodermatitis and chronic neuroborreliosis)

Diagnosis and Treatment of Lyme Disease

The Lyme-Borreliosis is primarily a presumptive clinical diagnosis that is supported by medical history and laboratory diagnostics. 80–90% of the patients with clinical neuroborreliosis will have the suspicion confirmed by a specific intrathecal antibody synthesis.

Pathogen detection: Serology-Step-by-Step diagnosis

  1. ELISA (or immunofluorescence test): Verification of antibodies (IgM/IgG) against B. burgdorferi in the enzyme-linked immuno-absorbent assay tests. Warning: the increase of the borrelia antibodies doesn’t have to always be detectable, or can be detectable a couple of days after the tick bite. The antibodies are not appropriate for the evaluation of the therapeutic process! After a successful antibiotic therapy, the antibodies can, over months to years, circulate in the cerebrospinal fluid. If the test for the first stage is positive, follow 2.
  2. Immunoblot (Western Blot): As confirmation test.

A positive antibody finding and corresponding clinical findings suggest Lyme-Borreliosis.

Note: If there is at the same time infection with syphilis, it may happen that false positive findings occur because of cross-reactions (TPHA test).

Overview of the Diagnostic and Therapy of the 3 Stages of Borrelia

Stage Diagnostic Therapy
Stage I Medical history of tick bites (50% of the patients don’t remember).

Antibody detection in the blood (successful in just 40% of the patients).

 

Doxycyclin or erythromycin p.o. for 2 weeks; for children and pregnant women: amoxicillin and cefuroxime; in case of intolerance: azithromycin
Stage II IgG-antibody detection in blood, confirmation test with Western Blot.

For Lyme arthritis: agent detection in punctate.

3rd generation Cephalosporin  (ceftriaxone) P

Penicillin G intravenous for 2–3 weeks if symptoms are particularly severe.

Stage III Antibody detection in blood and lymphatic tissue examination: lymphocytic pleocytosis, increased the percentage of protein, intrathecal Borrelia-specific IgG/IgM antibodies, and occasionally direct pathogen tests (Borrelia-DNA).  

3rd generation Cephalosporin intravenous for 2–3 weeks

Differential diagnosis of Lyme Disease

Dependent on the stage of the disease, there are many possibilities that can be considered for a differential diagnosis:

  • Other diseases with infection via ticks: FSME, anaplasmosis, and rickettsiosis
  • Neurological symptoms: multiple sclerosis
  • Joint inflammations: activated arthrosis and rheumatoid arthritis
  • If therapy is unsuccessful, search for tumors

Prophylaxis and Prevention of Lyme Disease

If the tick is removed within the first 12 hours, the risk to be infected with Borrelia is very low. For the removal, a tick tweezer should be used. For persons from non-endemic areas, there is no need for prophylactic antibiotics, but the site of the tick bite should be observed.

Precautions against ticks:

  • Adequate clothing
  • Repellents
  • Scanning the body for ticks after being outside (focus on the axillary and inguinal regions).
  • Create a tick-proof yard by clearing brush and leaves where ticks live and keeping wood piles in sunny areas.
  • Remove ticks from bite site as soon as possible and do not assume immunity is developed after the initial infection.
Note: There is no vaccine against Borreliosis yet. A person who already suffered from Borreliosis is not immune to a re-infection.

Complications of Lyme disease

  • Chronic joint inflammation (Lyme arthritis).
  • Neurological symptoms such as facial palsies and neuropathies.
  • Impaired memory.
  • Irregular heart rhythm.

Epidemic and Endemic Relapsing Fever

Epidemic relapsing fever Endemic relapsing fever
Agents Borrelia recurrentis. Borrelia duttoni
Transmission Lice (Pediculus humanus), “Relapsing fever due to lice,“ mainly in the cold season; lack of hygiene Lederzecken (Ornithodorus), “Recurrent fever” in Germany is known as imported travel disease.
Pathogenesis Pyrogenic effects by cell wall antigens
Symptoms Recurrent fever for 3–6 days, symptom-free intervals, chills, arthralgias, myalgias, stomach aches, hepatosplenomegaly, diffuse petechial hemorrhages, and pinpoint large macular exanthema.
Complications 30% of the patients develop seizures, coma, hemiplegia, CNS-bleedings, myocarditis with arrhythmia, and liver failure.
Diagnostic Serological diagnostics is unreliable! Detection of the pathogens in peripheral blood via dark-field microscopy.
Therapy Erythromycin, alternatively tetracycline
Lethality 2 – 5% Up to 40%
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