Chapter 5: Sexually Transmitted Infections

Sexually transmitted infections constitute a diverse and persistent public health concern, encompassing bacterial, viral, fungal, and parasitic organisms that compromise reproductive health and systemic wellness. The chapter systematically addresses infections affecting the vaginal environment, including vulvovaginal candidiasis caused by candida species, trichomoniasis from the protozoan trichomonas vaginalis, and bacterial vaginosis resulting from disruption of normal lactobacillus-dominated flora. Upper reproductive tract infections caused by chlamydia trachomatis and neisseria gonorrhoeae present particular clinical challenges due to their frequent asymptomatic presentation, enabling silent ascension to the uterus, fallopian tubes, and peritoneal cavity where they precipitate pelvic inflammatory disease with long-term sequelae including chronic pelvic pain, ectopic pregnancy, and infertility from tubal scarring. Genital ulcerative diseases, encompassing herpes simplex virus infection and the progressive stages of syphilis from primary chancre through tertiary neurosyphilis, carry significant implications for vertical transmission and adverse fetal outcomes including congenital infection and neonatal complications. The chapter examines human papillomavirus as an oncogenic pathogen with well-established links to cervical and other anogenital malignancies, vaccine-preventable hepatitis viruses affecting maternal and fetal health, and ectoparasitic conditions such as pubic lice and scabies. Substantial emphasis is devoted to human immunodeficiency virus infection and acquired immunodeficiency syndrome, exploring viral replication mechanisms, progressive CD4 lymphocyte depletion, immune reconstitution through highly active antiretroviral therapy regimens, and evidence-based interventions for preventing maternal-to-child transmission. Throughout, the chapter integrates comprehensive prevention and management strategies including consistent barrier method use, dual protection approaches combining contraception with disease prevention, behavioral risk reduction, regular screening protocols, and therapeutic approaches to reduce transmission rates and optimize maternal and fetal outcomes.