Eur. J. Epidemiol. 0392-2990 March 1993, p. 217-223 EUROPEAN JOURNAL OF EPIDEMIOLOGY Vol. 9, No. 2 ETIOLOGY OF TRAVELLER'S DIARRHEA IN SPANISH TRAVELLERS TO DEVELOPING COUNTRIES J. GASCON *l, J. VILA**, M.E. VALLS**, L. RUIZ*, J. VIDAL**, M. CORACHAN*, G. PRATS*** and M.T. JIMENEZ DE ANTA** *Secci6 Medicina Tropical del Hospital Clinic i Provincial (HCP) de Barcelona - Villarroel 170 08036 Barcelona, Spain. **Servei de Microbiologia - Parasitologia i Virologia - HCP- Barcelona, Spain. ***Servei de Microbiologia del Hospital de la Santa Creu i Sant Pau - Barcelona, Spain. Key words: Traveller's diarrhea - Tropical countries - Etiology A cohort of 337 Spanish travellers to developing countries is presented. They all consulted us for traveller's diarrhea (TD). Bacteriological, parasitological and virological examinations were performed. A bacterial cause was found in 61.650/0 of travellers. Toxigenic and classical pathogenic Escherichia coli strains were the main bacterial agents. In comparison with other studies, Spanish travellers harboured Y. enterocolitica and EPEC organisms as a cause of TD. G. lamblia and E. histolytica were the most frequently isolated protozoa. Helminths were found in only 9 patients. No rotavirus infections were diagnosed. Previous antibiotic treatment had been taken by 161 patients. The percentage of isolated enteropathogens was similar in travellers who had previously taken antibiotic treatment and those who had not. INTRODUCTION Over the last few years, the number of Spanish travellers to tropical areas has greatly and Spain has also received an increasing number of immigrants from various African countries, which has meant an increase in imported diseases that we see nowadays in our centres (8). On a world scale, Spain is considered to be an intermediate risk area for "travellers diarrhea" (TD), and this could indicate the presence of an acquired immunity to enteropathogens among Spanish residents which is different from that of residents of other European countries. Therefore, we decided to compare the incidence of enteropathogenic microorganisms that affect Spanish travellers to tropical countries with other t Corresponding author. studies. The second aim of the study was to determine the distribution of microorganisms according to geographic area from which travellers had come. MATERIALS AND METHODS Patients who attended our clinic suffering from TD after a trip shorter than 90 days (mean duration 29.18 days) to developing countries, over a period of 3 years (July 1988 to February 1991) were included in the study. TD was defined according to Merson's criteria (22) as the occurrence between 12 hours after arrival in, and five days after departure from the country visited, of three or more episodes of watery diarrhea within a 24-hour period with or without other symptoms; or, as the occurrence of unformed stools accompanied by one of the following: abdominal cramps, tenesmus, vomiting, nausea, fever, chills or prostation. 217