The present study aims to investigate the performance characteristics of both established and new assays for Borrelia burgdorferi infection and to assess the relative performance of appropriate combinations of these tests. The study will also investigate the effect of the time course of the infection and its treatment on the outcomes for the various tests. Polymerase Chain Reaction(PCR), serology and T cell based tests will be performed. In addition, tests for Babesia, Anaplasma, Ehrlichia and Rickettsia will also be performed as these pathogens can be carried by the same tick that carries Borrelia and may result in coinfection.