Recent trends in infectious diseases for travellers.

In the early 1970s medicine was considered to have conquered infectious diseases. The following three decades have shown this optimism to be misplaced, with both traditional infections increasing in prevalence and novel diseases appearing. Many of these diseases have become major problems in developing countries, and coupled with the exponential growth in international traffic now pose a significant risk to the traveller. The threat to the package tourist differs greatly from that to the businessman, soldier or backpacker. The latter groups may have little control over their food and water supplies and be exposed to vector-borne and zoonotic infections normally restricted to remote locations. However the package holidaymaker may be involved in mass outbreaks of food poisoning with novel pathogens or acquire unusual infections from close proximity to other tourists. All groups may be susceptible to diseases transmitted during travel, and these may be more common than is presently recognised. The common factor is that all such infections may be transported around the world within their incubation period, and that any disease can now present to any doctor. Today more than ever before it is incumbent on any practitioner to ask not only 'where have you been?' but also 'what were you doing there?'