Laboratory diagnostics of syphilis. Modern approaches and perspectives. Part I. Epidemiology. Direct diagnostic methods

Background. Syphilis is a chronic systemic infection caused by T. pallidum. Despite the health authorities’ efforts to prevent the disease prevalence, syphilis continues to be registered in many countries of the world including the Russian Federation causing severe complications like visceral syphilis, congenital syphilis. The disease is often latent that determines the high requirements for laboratory diagnostics. Objective. To highlight some issues of syphilis’ epidemiology and its direct diagnostic methods. Results and discussion. The article provides modern data on syphilis prevalence in the Russian Federation, as well as in Europe and the United States based on official statistics. Most of the review is devoted to the direct research methods used to reveal syphilis: dark-field microscopy, direct immunofluorescence, immunohistochemistry, tissue hybridization, polymerase chain reaction (PCR). Since PCR diagnosis of syphilis are contradictory a number of works reflect in more detail on various aspects of this method usage. Such variants as routine PCR, PCR with reverse transcriptase, nested PCR, real-time PCR, multiplex PCR are covered. Examples of method usage in various biological samples (syphilide material, blood, cerebrospinal fluid, sperm, etc.), its sensitivity and specificity and further prospects are given. The article guides the various specialties who encounter patients with syphilis as well as scientific workers; the possibilities of laboratory diagnosis of syphilis by direct methods, their advantages and disadvantages, and prospects for use are given. © 2021, Media Sphera Publishing Group. All rights reserved.