Epidemiology The prevalence and incidence of sexually transmittedinfections vary in different parts of the world. This is dueto variations both in the diseases found and in the methodsof reporting such infections. The type of sexual behaviourand the sexual orientation of the person involved alsoinfluence the transmission of the infectious agents. This isclearly demonstrated by the fall in incidence of syphilis andgonorrhoea after the introduction of penicillin, the rise in incidence in the 1960s due to an increasein the number of people's sexual partners, followed by asubstantial fall in the 1980s, when the AIDS epidemicresulted in a change in sexual behaviour in homosexualmen.This is an underestimateof the problem. Morbidity associated with STD ismore common in women and the agents responsible aremore difficult to identify.Reported STDs are observed mostly in the 20-24-yearoldage group, followed by 25-29 and 15-19-year-olds. Inthe western world male homosexuals are more likely tocontract hepatitis B, syphilis and HIV infection than aretheir heterosexual counterparts. However, the incidence ofnewly acquired syphilis and gonorrhoea in homosexualmen fell as trends in sexual behaviour changed in the 1980s.The basis of any STD service is the control of sexuallytransmitted infections. There are basic requirements: The patient needs ready access to a specialist centre foraccurate diagnosis and treatment of any infection.Attendance needs to be voluntary. Treating the indexcase only partly helps in controlling an infection, andtherefore sexual partners need to be identified andtreated. Patients are much more likely to cooperate in thesematters if they are assured of absolute confidentiality.The STD service is the most confidential are in thehealth service, and details are generally only releasedwith the patient's consent. Education about STDs, both for an individual and aspart of general health education, is important in helpingto control the spread of infection. The clinics keep a record of the number of patients seenwith each infection, and these figures form part of adetailed national epidemiology report.
