Borrelia afzelii nucleic acids were detected in the sera of febrile disease patients by a nested PCR that targeted the rrf (5S)‐rrl (23S) spacer of B. burgdorferi sensu lato. The B. afzelii‐specific DNA fragment was detected in 8 out of 283 sera which were proven to have immunoglobulin G or M antibodies against B. burgdorferi antigens through IFA. The results were further confirmed through restriction fragment length polymorphism and sequencing analysis of the DNA fragments. The results indicated for the first time that Lyme borreliosis is prevalent in Korea.

In this study the diagnostic potential of Rickettsia conorii recombinant antigens was analyzed. For this, site-specific PCR primers were used to clone the OmpA and OmpB genes of R. conorii into pMAL-c2X plasmids. Six fragments of OmpA and four of OmpB were expressed as fusion proteins with maltosebinding protein in Escherichia coli. OmpA 1350−1784 , OmpB 801−1269, and OmpB 1227−1634 regions from truncated proteins were selected as diagnostic candidate antigens by ELISA using control sera. ELISA results of three antigens were compared to the results obtained by using a commercial ELISA kit which contained whole OmpA and OmpB antigens from R. conorii. For this analysis, 40 serum samples taken from febrile patients and uninfected controls were tested. Of the 20 R. conorii test results which were positive with the commercial kit, 18 were shown to be positive by ELISA using OmpA 1350−1784 (a sensitivity of 90%). The specificity of the ELISA was 100%; all of the 20 samples shown to be negative using the commercial kit were also negative in our assay. The sensitivities of the ELISA using the OmpB 801−1269 and OmpB 1227−1634 were 90% and 95%, respectively. The specificities of the OmpB 801−1269 and the OmpB 1227−1634 were 100% and 95%, respectively. These results suggest that specific regions of OmpA and OmpB effectively detect antibodies against R. conorii, and the truncated recombinant antigens could be used for development of diagnostic tools for rickettsial disease.