Lyme Disease: Diversity of Borrelia Species in California and Mexico Detected Using a Novel Immunoblot Assay

Abstract

Background: With more than 300,000 new cases reported each year in the United States of America (USA), Lyme disease is a major public health concern. Borrelia burgdorferi sensu stricto (Bbss) is considered the primary agent of Lyme disease in North America. However, multiple genetically diverse Borrelia species encompassing the Borrelia burgdorferi sensu lato (Bbsl) complex and the Relapsing Fever Borrelia (RFB) group are capable of causing tickborne disease. We report preliminary results of a serological survey of previously undetected species of Bbsl and RFB in California and Mexico using a novel immunoblot technique.

Methods: Serum samples were tested for seroreactivity to specific species of Bbsl and RFB using an immunoblot method based on recombinant Borrelia membrane proteins, as previously described. A sample was recorded as seropositive if it showed immunoglobulin M (IgM) and/or IgG reactivity with at least two proteins from a specific Borrelia species.

Results: The patient cohort consisted of 90 patients residing in California or Mexico who met the clinical case definition of chronic Lyme disease. Immunoblot testing revealed that 42 patients were seropositive for Bbsl (Group 1), while 56 patients were seropositive for RFB (Group 2). Eight patients were seropositive for both Bbsl and RFB species. Group 1 included patients who were seropositive for Bbss (14), B. californiensis (eight), B. spielmanii (10), B. afzelii/B. garinii (10), and mixed infections that included B. mayonii (three). Group 2 included patients who were seropositive for B. hermsii (nine), B. miyamotoi (seven), B. turicatae (nine), and B. turcica (two). In the remaining Group 1 and Group 2 patients, the exact Borrelia species could not be identified using the immunoblot technique.

Conclusions: Lyme disease is associated with a diverse group of Borrelia species in California and Mexico. Current testing for Lyme disease focuses on detection of Bbss, possibly resulting in missed diagnoses and failure to administer appropriate antibiotic therapy in a timely manner. The genetic diversity of Borrelia spirochetes must be considered in future Lyme disease test development.

Keywords: Borrelia burgdorferi; Borrelia miyamotoi; Lyme disease; Relapsing Fever Borrelia; immunoblot; tickborne disease.

Figure A1

Immunoblot reactivity for Borrelia burgdorferi sensu lato (Bbsl). Immunoblot strips with recombinant Borrelia antigens were incubated with representative patient serum samples, as described in Section 2. Blots were interpreted according to IGeneX criteria (see text). P—positive control; N—negative control; G—Bbsl immunoblot immunoglobulin G (IgG); M—Bbsl immunoblot IgM; Lane 1—B. burgdorferi B-31 positive IgM and IgG; Lane 2—B. mayonii positive IgG; Lane 3—B. speilmanii positive IgG; Lane 4—B. californiensis positive IgM and IgG; Lane 5—mixed infection B. mayonii and B. californiensis positive IgM; Lane 6—B. burgdorferi European species positive IgM and IgG; Lane 7—Bbss and B. burgdorferi European species positive IgM.

Figure A2

Immunoblot reactivity for Relapsing Fever Borrelia (RFB). Immunoblot strips with recombinant Borrelia antigens were incubated with representative patient serum samples, as described in Section 2. P—positive control; N—negative control; G—RFB immunoblot IgG; M—RFB immunoblot IgM; 1—B. hermsii positive IgM; 2—B. turicatae positive IgG; 3—B. miyamotoi positive IgM; 4—B. turcica-like positive IgG.