Sexually Transmitted Infections: Epidemiological Trends, Diagnostics, and Emerging Treatment Challenges

Sexually transmitted infections (STIs) represent a global public health challenge of considerable magnitude, with rising global incidence of syphilis, gonorrhoea, chlamydia, and mpox reflecting complex interactions between changing sexual behaviour, diagnostics, access to healthcare, and antimicrobial resistance. This chapter provides a comprehensive update on the epidemiology, pathogenesis, and clinical manifestations of major STIs, with particular attention to the re-emergence of syphilis in diverse population groups, the accelerating global spread of antibiotic-resistant Neisseria gonorrhoeae, and the expanding repertoire of point-of-care diagnostic platforms. Prevention strategies — including pre-exposure prophylaxis, vaccination, and public health interventions — are reviewed alongside the latest treatment guidelines.