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

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. sensu stricto (Bbss) is considered the primary agent of Lyme disease in North America. However, multiple genetically diverse species encompassing the sensu lato (Bbsl) complex and the Relapsing Fever (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 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 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), (eight), (10), (10), and mixed infections that included (three). Group 2 included patients who were seropositive for (nine), (seven), (nine), and (two). In the remaining Group 1 and Group 2 patients, the exact species could not be identified using the immunoblot technique.

CONCLUSIONS

Lyme disease is associated with a diverse group of 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 spirochetes must be considered in future Lyme disease test development.