Incidence of Intestinal Protozoal Infection in Traveller's Diarrhoea

Stools examination for intestinal protozoa in patients of traveller's diarrhoea were carried out in 1983 and 1984 (the 1st period), and in the period from July, 1985 to June, 1986 (the end period). Results obtained were as follow: 1) In the 1st period, stools from 1, 256 patients who had oversea travel over 5 days were examined. Seven species of intestinal protozoa, including 39 cases with Giardia lamblia, were detected (3.9%). 2) 98% of all the positive cases were the travellers over 10 days and 67.4% were travellers over 30 days. 3) An aparent seasonal variation was recognised in the positivity rate. 4) 92% of the positive cases with Giardia lamblia (1st period) visited India, 64% Thailand, 41% Nepal. More than 70% of Giardia lamblia positive cases among travellers to India or Nepal, stayed over 10 days in the respective countries. 5) In the 2nd period, stools from 178 patients who stayed in India and/or Nepal more than 10 days were examined. Three species of intestinal protozoa, including 25 cases with G. lamblia were detected (14.0%). 6) 64 cases with G. lamblia were summarizes though the 1st and 2nd periods of examination. In 29 cases among them, some species of pathogenic bacteria or other species of intestinal protoxoa were concomitanly detected. 7) The positivity rate of G. lamblia in travellers who stayed over 10 days in India and/or Nepal was 12.9% in 1983 and 12.2% in 1984, and not significantry different from that (14.0%) in the 2nd period.