International travel and sexually transmitted diseases.

Sexually transmitted diseases (STDs) are a group of communicable diseases transferred mainly by sexual contact. Population movements are undoubtedly a major contributing factor in the spread of STDs. Owing to the ease of modern travel, larger numbers of people are moving around than ever before in peacetime. Travellers may both import and export infection, and the importance of their role in the transmission of STDs is demonstrated by the rapid worldwide spread of penicillinase-producing strains of N. gonorrhoeae (PPNG) and AIDS. While in most industrialized countries the incidence of the classic STDs (syphilis, gonorrhoea, chancroid) has decreased during the last decade, they remain hyperendemic in many developing countries due to poorly developed STD services. In many industrialized countries, the incidence of genital C. trachomatis infection now exceeds that of gonococcal infection. Chlamydial infections were previously thought to be infrequent in developing countries, but recent research has made it clear that this infection is at least as frequent as gonorrhoea. Incidence of genital herpes and genital human papilloma-virus infections (HPV) has increased dramatically during the last 20 years. Now that international travel takes place increasingly by air, it is more likely than previously for a traveller to return home within the incubation period of many STDs. Moreover, people behave differently when they travel. Tourists travel to seek adventure and new experiences, including sex. In countries where a good notification system exists, up to 30% of new cases of syphilis were found to be acquired abroad. Since PPNG appeared in 1976, these strains have spread to almost all areas of the world. During the first five years of the epidemic, most cases in Europe and the United States of America were imported. Measures for preventing STDs are the same whether the individual is travelling or not. Abstinence or sexual intercourse between two mutually-faithful uninfected partners exclusively are the only totally effective prevention strategies. The risk of infection can also be significantly reduced by adopting safe sexual practices such as the use of condoms. Prophylactic use of an antibiotic is not recommended, however.