Advances and pitfalls in the diagnosis of Lyme disease.

Abstract

Lyme disease is one of the major emerging infections of the past decade. This global vector-transmitted disorder is due to a tick-borne spirochete named Borrelia burgdorferi , after its discoverer [1]. Lyme disease is geographically restricted to regions inhabited by the critical tick vector. Organisms are transmitted through the bite of infected Ixodid (hard body) ticks, particularly those belonging to the Ixodes persulcatus complex. They include I. scapularis in the northeast and midwest United States, I. pacificus in the western United States, I. ricinus in central and western Europe, and I. persulcatus in Asia. B. burgdorferi belongs to the genospecies complex B. burgdorferi sensu lato. This complex is genetically divided into multiple genospecies, including B. burgdorferi sensu stricto, B. garinii, B. afzelii, B. japonica, B. andersoni , and others [2]. Considerable genetic diversity exists among B. burgdorferi in both Europe and the United States, and different genospecies may predominate within different geographic areas. There are preliminary associations between specific strains and clinical disease patterns. A single tick may be infected with several different B. burgdorferi strains. It is likely that spirochete strain heterogeneity, as well as host immune and genetic factors, play a role in the development of Lyme disease. Although Lyme disease is a systemic infection, it has specific target organs (skin, nervous system, joint, heart, eye). Characteristic clinical syndromes are associated with early stage local infection, early stage disseminated infection, and late stage disseminated infection (Table 1). Cutaneous disease, followed by neurologic disease, is the most common feature [3]. View this table: Table 1 Clinical syndromes associated with Lyme disease At the current time, the diagnosis of Lyme disease is made on clinical and epidemiologic grounds. It is based on endemic area exposure, tick exposure, presence of abnormal symptoms and signs consistent with B. burgdorferi infection, failure to establish an …