George R. Kinghorn and Rasha Omer
Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
The global health burden of sexually transmitted infections and HIV is large and increasing. The World Health Organization (WHO) estimates that there are around 498 million people aged 15–49 years who are infected each year with chlamydia, gonorrhoea, syphilis or trichomoniasis [1]. If the major viral sexually transmitted infections (STIs) are added then the prevalence may be increased threefold. However, the true prevalence is unknown, because surveillance is inadequate in many countries, especially in resource-poor countries in sub-Saharan Africa, South-East Asia and the Americas, where the sexual ill health burden is greatest.
The incidence of STIs depends as much upon social and economic factors as upon biology and behaviour. STIs thrive in situations where communities are disrupted by conflict and war, where there is a high dependence upon migrant labour that disrupts families and where commercial sex work is prevalent. They are also promoted by stigmatization, which delays presentation for treatment and reduces the resources employed for their control.
STIs are caused by a diverse group of microorganisms. Many individuals have asymptomatic early infections, and this favours onward transmission. The later complications are a serious cause of morbidity and mortality, and can adversely affect reproductive health in women. STIs are a major cause of infertility as a result of damage to the fallopian tubes from ascending infections. Adverse pregnancy outcomes in terms of ectopics, miscarriage and stillbirth are common. Postabortal and postpartum infections related to STI are thought to cause around one-third of maternal deaths worldwide. Morbidity and mortality for the fetus also occur as a result of preterm birth associated with many STIs, and from vertical transmission causing congenital infections. Premature death in adults of both sexes may also result from genital cancers associated with human papillomavirus infections and liver disease associated with sexually transmitted hepatitis B and hepatitis C. However, the greatest loss of life is now associated with HIV infection, and the synergy with STIs which favours acquisition and transmission of HIV places even greater importance upon public health control measures.
Treatment and prevention of STIs are very cost-effective and the WHO has developed a global strategy for their control [2]. This requires a coordinated, multiagency approach involving both health education and other government services. Behaviour change and promotion of condom use can reduce individual risk. There should be appropriate health care services for both diagnosis and treatment. Improved surveillance should underpin the development of local strategic planning.
A coordinated approach that has been given strong political support has been found, in some countries, to reverse rising trends in HIV and STI incidence. This will be reinforced if there are also continuing efforts to improve clinical recognition and management of these conditions.