[Imported respiratory infections: new challenges and threats].

term " imported diseases " refers to infectious processes that are acquired in areas where they are more or less common but which are diagnosed and treated in places where they are not found or are extremely rare 1. In clinical practice these diseases appear amongst two very different groups: travelers coming back from underdeveloped countries and immigrants who come from those parts of the world. The difference is an important one as the agents responsible for respiratory diseases tend to be different in each group. In Spain, the detection of imported diseases has been rare but is becoming more common with the increase in tourism to exotic regions and particularly the rise in immigration. There are approximately 1 000 000 immigrants from developing countries living in Spain (700 000 legally and 300 000 illegally) 2. Likewise, between 700 000 and 1 000 000 Spaniards 3,4 travel to underdeveloped countries where they may be exposed to pathogens. Although imported diseases are rare in individual clinical practices, the growth of both phenomena (immigration and travel) means that in general these diseases will be gradually included in the differential diagnosis of many clinical syndromes. There are noninfectious agents that are known to affect the lungs more frequently in the tropics 5 (such as tobacco, rheumatic cardiopathy, pneumoconiosis or illnesses caused by organic dust) and which must not be overlooked. However, the most common imported respiratory diseases are infections and conclusions can be drawn from a basic analysis: a) most infections detected in immigrants and, to a lesser extent, in travelers are caused by the same etiological agents that cause lung disease in the immigrants' countries of origin; b) the main imported respiratory problem is tuberculosis, and c) some apparently " exotic " infections are already present in Spain, although they are not well known. We will comment briefly on the two last points. Imported tuberculosis occurs mainly amongst immigrants though tuberculous infection is now found increasingly amongst travelers to high endemic countries both during their journeys 6 and during longer stays 7. Characteristics of tuberculosis in immigrants, as opposed to tuberculosis in the local Spanish population 8,9 , can be summarized as follows: a) frequency is higher than in the local population (approximately one in ten cases appears in an immigrant); b) the disease normally develops two to three years after the immigrant arrives in Spain; c) in general the disease is …