Borrelia yangtzensis IgG

Borrelia spp. are spirochetes responsible for Lyme disease (LD) and relapsing fever (RF). They are transmitted primarily by ticks and lice and cause a range of symptoms, including fatigue, fever, and musculoskeletal pain. 

As the distribution of Borrelia-carrying ticks expands, clinicians must be vigilant in diagnosing and managing these infections, particularly with the emergence of new species like Borrelia yangtzensis, which has been linked to human illness in East Asia.

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, and 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.

What is Borrelia yangtzensis?

Borrelia yangtzensis is a newly recognized species of Lyme borreliosis (LB) spirochete, primarily found in rodents and Ixodes ticks in East Asia, including China, Japan, and Malaysia. It is genetically distinct from other LB species, particularly B. valaisiana, which is bird-transmitted. 

B. yangtzensis has been linked to human infections. The first reported case occurred in Korea in a patient who developed symptoms following a tick bite. Symptoms included a papular rash and headache, and diagnosis was confirmed through molecular and serological testing. 

While it is closely related to B. valaisiana, its clinical significance is still emerging, and further research is needed to understand its potential to cause Lyme disease or other tick-borne illnesses in humans. 

This species is transmitted by Ixodes ticks and has been identified in rodent hosts, suggesting its role in zoonotic transmission. The discovery of B. yangtzensis in new geographic areas, including Malaysia, highlights its expanding range and potential as an emerging zoonotic pathogen.

What is Borrelia yangtzensis IgG?

Borrelia yangtzensis IgG is a type of antibody produced by the immune system against DbpA. These antibodies remain detectable long after the infection resolves, serving as markers of past or present infection.

While IgG antibodies to B. yangtzensis can be present in both active and past infections, their presence alone does not confirm active disease. 

Who Should Get Tested for Borrelia yangtzensis IgG?

Testing for Borrelia yangtzensis IgG may be considered for:

• Patients with a history of tick bites and symptoms consistent with Lyme disease or other tick-borne illnesses, where chronic or past infection is suspected, as IgG antibodies indicate prior or ongoing exposure.
• Individuals with chronic symptoms such as fatigue, headache, or musculoskeletal pain after potential exposure to ticks in endemic regions like East Asia (China, Japan, Malaysia) may consider testing for IgG antibodies to determine if B. yangtzensis infection occurred.

Test Procedure and Interpretation

The following section outlines testing procedures and results interpretation for IgG antibodies against various Borrelia species:

Test Procedure and Preparation Requirements

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

Normal Reference Ranges

Normal reference ranges for Borrelia IgG may vary slightly depending on the laboratory performing the test. However, a negative result generally indicates no detectable immune response to Borellia species 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 IgG levels typically indicate that the patient has been exposed to Borellia pathogens in the past or is currently experiencing an active infection. However, since IgG antibodies can persist after infection has cleared, high levels do not necessarily confirm active disease. 

Elevated IgG levels should be interpreted alongside the patient’s clinical history and symptoms, with further diagnostic tests, such as IgM testing or PCR, used to confirm the diagnosis.

Order Lyme Disease Testing

Click here to compare testing options and order tests for Lyme disease.