Borrelia garinii

Borrelia garinii is a spirochete and a primary cause of Lyme neuroborreliosis (LNB) in Europe, often associated with clearer early diagnoses and presenting with symptoms such as radicular pain and meningitis. 

Recent genomic confirmation of B. garinii in rodents from South Carolina, USA, suggests a potential spread of this pathogen to new regions, emphasizing the importance of clinical vigilance for its detection, especially in patients with neurological Lyme disease or those from endemic areas.

What is Borrelia?

Borrelia spp. are spirochetes responsible for Lyme disease (LD) and relapsing fever (RF), transmitted by ticks and lice. 

LD, caused by Borreliella spp. (formerly Borrelia), is the most common vector-borne disease in temperate regions. It is primarily caused by B. burgdorferi and B. mayonii, but it is also caused by B. afzelii and B. garinii.

Symptoms include erythema migrans, fatigue, fever, and musculoskeletal pain. Untreated infections can lead to neuroborreliosis, arthritis, and Lyme carditis. 

RF, caused by species like B. miyamotoi, B. hermsii, and Candidatus B. johnsonii, presents with recurring fever, headache, myalgia, and can cause severe complications, including meningitis.

Borrelia spp. are commonly found in ticks that infest rodents, birds, and wild ungulates. The distribution of these ticks, particularly in the Mediterranean and the U.S., has expanded, increasing the prevalence of Borrelia infections. 

A recent study identified five Borrelia species in U.S. patients, including B. burgdorferi and B. mayonii (LD), and B. miyamotoi, B. hermsii, and Candidatus B. johnsonii (RF). The discovery of Candidatus B. johnsonii, previously linked only to bat ticks, suggests it may also cause human illness.

Clinicians should be aware of the distinct clinical features of LD and RF for timely diagnosis and treatment. Preventative measures like tick repellents are foundational in reducing transmission. 

What is Borrelia garinii?

Borrelia garinii is a subspecies of Borrelia burgdorferi sensu lato. It is a primary cause of Lyme neuroborreliosis in Europe and is known for producing clearer clinical diagnoses than B. afzelii. 

Patients infected with B. garinii are more likely to receive reliable diagnoses early. Common symptoms include radicular pain, meningeal signs, and lymphocytic pleocytosis in cerebrospinal fluid (CSF), while dizziness is less common. 

It is most often associated with Bannwarth syndrome, a typical presentation of early Lyme neuroborreliosis. 

Recently, B. garinii was identified in rodents in South Carolina, USA, marking its first genomic confirmation in the region. These isolates (SCCH-7 and SCGT-19) are closely related to Eurasian strains, suggesting that B. garinii may have migrated from Europe or Asia, rather than from Canada, where it has previously been found. 

Although no Lyme disease outbreaks were reported in the southeastern U.S. at the time, the discovery calls for clinical vigilance for B. garinii infections in the area.

Symptoms of Lyme Neuroborreliosis

Lyme neuroborreliosis (LNB) is a neurological manifestation of Lyme disease caused by Borrelia bacteria. It primarily presents as polyradiculitis or meningoradiculoneuritis. 

Polyradiculitis and meningoradiculoneuritis, also known as Bannwarth syndrome, commonly present with severe, zoster-like segmental pain, often worse at night and poorly responsive to standard pain relief. 

Patients typically develop neurological deficits, such as flaccid paralysis or segmental sensory disturbances, within 1–4 weeks, with facial nerve involvement leading to peripheral facial palsy in about 60% of cases.

Who Should Be Tested for Borrelia garinii?

Given its clinical significance, testing for B. garinii should be considered for:

Individuals with Neuroborreliosis

Since B. garinii is frequently associated with neurological Lyme disease, testing should be considered for patients presenting with neurological symptoms like facial palsy, meningitis, or other central nervous system involvement.

Individuals with Lyme Disease Symptoms

Those who have been exposed to tick habitats in Europe or Asia, where B. garinii is prevalent, should be considered for testing.

Travelers or Residents in Endemic Regions

People living or traveling in areas where B. garinii is common (such as parts of Europe and Asia) should be tested if they exhibit symptoms of Lyme borreliosis or have been bitten by ticks.

People with Unexplained Skin or Joint Symptoms

Given B. garinii's role in Lyme disease pathogenesis, individuals experiencing chronic or atypical skin or joint symptoms could benefit from testing, particularly if they live in or have traveled to endemic regions.

Diagnostic Requirements for Lyme Disease

Diagnosing Lyme disease involves a combination of clinical evaluation, history of tick exposure, and laboratory tests. 

To test for Lyme disease, serologic testing is used. The CDC recommends a two-step process: an enzyme immunoassay (EIA) followed by a Western blot for confirmation. IgM antibodies indicate recent infection, while IgG antibodies appear later.

Early serologic tests may be unreliable, so PCR and CSF analysis are used in suspected neuroborreliosis or Lyme arthritis for various Borrelia species. Early diagnosis and treatment are essential to prevent complications.

Test Procedure and Interpretation

The following section outlines testing procedures and results interpretation for Borrelia garinii:

Test Procedure and Preparation Requirements

Borrelia garinii testing may require a blood sample, and/or CSF sample if concern for lyme neuroborreliosis is present. 

A blood sample is typically collected via venipuncture. CSF sample collection is more invasive and typically involves a lumbar puncture. 

There are generally no specific preparation requirements for the patient, although it’s always important to confirm this with the ordering provider.

Normal Reference Ranges

Normal reference ranges for Borrelia garinii may vary slightly depending on the laboratory performing the test. However, a negative result generally indicates no detectable presence or immune response to B. garinii at the time of testing. 

Clinical Implications of Elevated Levels

Elevated Borrelia garinii levels typically indicate that the patient is currently experiencing an active infection. Positive antibody responses must be interpreted within the context of the individual’s presentation and medical history.

Positive results, especially the presence of the bacterium in the context of clinical symptoms, indicate a current infection that requires treatment.

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