an infection that is passed from one person to another during sexual activity (the abbreviation for ‘sexually transmitted infection’) 性传播感染,性行为造成的感染(全写为 sexually transmitted infection) a fact sheet on the symptoms and treatment of STIs 关于性传播感染症状和治疗的概况介绍 STIs cause a wide range of illnesses. 性传播感染会导致多种疾病。