[Studies on Vibrio cholerae non-O1 isolated from diarrheal patients arrived from overseas]

Between the period January 1991 to June 1993, there were 23,976,238 travellers who arrived from overseas to Narita Airport, of which 20,501 stool specimens were collected from diarrheal patients for bacteriological examination, and infectious agents were detected from 2,751 cases (13.4%) including 250 cases (1.2%) of Vibrio cholerae non-O1. Countries suspected of infection of these patients were Thailand, the most in number, and followed by Indonesia, India and so on these mostly distributed in South-east or South Asia. About fifty percent of the patients were associated with abdominal pain and some with vomiting or fever. Diarrhea was mostly mild except in 16 patients who had severe diarrhea of more than ten times a day. 237 of the 250 isolated V. cholerae non-O1 strains were classified into 48 serogroups. There were 2 rough strains and 11 other strains which were out of the confirmed serogroups. Positive rate of these strains to haemolysin, cholera toxin (CT) and NAG-ST tests were 87.2, 0.4 and 0.8% respectively.