[Sexually transmitted infections: epidemiology and control]

Sexually transmitted infections (STI) include a group of diseases of diverse infectious etiology in which sexual transmission is relevant. The burden of disease that STI represent globally is unknown for several reasons. Firstly, asymptomatic infections are common in many STI; secondly, diagnostic techniques are not available in some of the most affected countries; finally, surveillance systems are inexistent or very deficient in many areas of the world. The Word Health Organization has estimated that in 1999 there were 340 million new cases of syphilis, gonorrhoea, chlamydia infection and trichomoniasis. An increasing trend in the incidence of gonorrhoea and syphilis has been noticed in the last years in the European Union, including Spain. Co-infection with other STI, especially HIV, should be ruled out in all STI patients. Chlamydia screening is also of particular importance since this is the most common STI in Europe and frequently goes unnoticed. STI prevention and control should be based on health education, early diagnosis and treatment, screening for asymptomatic infections, contact investigation and vaccination for those diseases for which a vaccine is available.