Borrelia afzelii OspA IgM

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

LD is the most common vector-borne disease in temperate regions, primarily caused by Borreliella spp. (formerly Borrelia), including B. afzelii, which is particularly linked to dermatological manifestations like erythema migrans, borrelial lymphocytoma, and acrodermatitis chronica atrophicans.

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 of LD 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. 

Ongoing surveillance and rapid intervention are essential for understanding and managing Borrelia infections.

What is Borrelia afzelii?

Borrelia afzelii is a species of Borrelia burgdorferi sensu lato (B. burgdorferi s.l.), and is a primary cause of Lyme disease (LD) in Europe. Predominantly transmitted by Ixodes ricinus ticks, it is found in regions including Spain, France, Italy, Slovenia, Croatia, Greece, Turkey, and Egypt. 

It is particularly linked to dermatological manifestations like erythema migrans, borrelial lymphocytoma, and acrodermatitis chronica atrophicans (ACA). The species tends to cause localized skin infections rather than systemic symptoms like neuroborreliosis or arthritis, which are more commonly associated with other species like Borrelia burgdorferi sensu stricto (B. burgdorferi s.s). 

B. afzelii is the most prevalent Borrelia species in European ticks, with minimal transmission time from tick bite to infection. Genetic diversity within B. afzelii has been noted, with multiple genotypes identified, which may influence transmission and virulence. 

What is Borrelia afzelii OspA?

Borrelia afzelii OspA (outer surface protein A) is a protein found on the surface of the Borrelia afzelii bacteria. 

While the OspA protein is not essential for Borrelia’s infection in mammals, it is important for its survival and disease transmission. This protein helps the bacteria attach to cells in the tick’s gut, allowing it to survive and be transmitted to mammals, including humans, when the tick feeds.

What is Borellia afzelii OspA IgM?

Borrelia afzelii OspA IgM is a type of antibody produced by the immune system against the OspA protein. 

IgM antibodies against Borrelia afzelii OspA are typically produced during the early stages of infection. They indicate an active or recent infection with Borrelia afzelii, as they are the first antibodies to appear in the immune response and activate the complement system to fight the bacteria. 

Elevated IgM levels, especially in the context of clinical symptoms like erythema migrans or other Lyme disease manifestations, can help confirm an active infection.

Who Should Get Borrelia afzelii OspA IgM Tested?

Common symptoms of Borrelia afzelii infection that should prompt testing include skin issues like erythema migrans (a red, circular rash often with a "bull's-eye" appearance) and acrodermatitis chronica atrophicans (ACA), which starts as red-blue swelling and may lead to skin thinning and atrophy, usually on the hands and feet. 

Another symptom is borrelial lymphocytoma, a small, bluish-red nodule that typically appears on the ear or breast.

These symptoms, combined with a history of potential tick exposure in endemic areas, warrant testing for B. afzelii and other related Borrelia species.

Testing for this specific biomarker is especially relevant in regions where B. afzelii is common, such as parts of Europe. Additionally, individuals with persistent symptoms despite negative Lyme disease testing may benefit from further evaluation, as initial tests can yield false-negative results, especially in the early stages of infection.

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 a variety of 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 afzelii OspA IgM:

Test Procedure and Preparation Requirements

Borrelia afzelii OspA IgM testing requires a blood sample, typically collected via venipuncture. The patient generally does not have specific preparation requirements, although it’s always important to confirm this with the ordering provider.

Normal Reference Ranges

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

Positive results, especially in the context of clinical symptoms, suggest past or ongoing infection.

Clinical Implications of Elevated Levels

Elevated Borrelia afzelii OspA IgM levels typically indicate a recent or active infection, helping to diagnose Lyme disease in its early stages, particularly when combined with relevant clinical symptoms.

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