Screening the returned traveller.

Large numbers of people return to the UK each year (estimated at 2 million in 1990) from tropical areas where they may have been exposed to a variety of tropical infections. Some will seek medical help because of specific symptoms, whilst others who are asymptomatic will request screening investigations to reveal latent infections which might give rise to symptoms later in life. A third group will ask for help with retrospective diagnosis of illnesses suffered whilst abroad. People from all three groups may express concern about the risk of passing on infections to close contacts or may be worried about their fitness to return to the tropics. The precise value of screening for tropical illness is hard to quantify, as the chance of finding an important treatable illness in any one individual will depend on the level of risk of infection to which that individual has been exposed. In some groups of travellers such as refugees, screening is clearly worthwhile, whilst in others whose risk of serious infection is low, the benefit is likely to be small. Nevertheless a demand for screening after tropical travel exists, and it is important to be aware of how to investigate for asymptomatic disease in returned travellers who request screening.