[Prevalence of intestinal parasites among Japanese residents in developing countries]

We examined fecal specimens of Japanese residents in developing countries in order to know the prevalence of intestinal parasites in the group. One fecal specimen was collected from each 981 (in 1995) and 1275 (in 1996) Japanese living in Asia, the Middle East, Europe, Africa and Latin America. The specimens were fixed with 10% formalin in each area, and were examined in Japan by concentration method (formalin-ether sedimentation) to find protozoan cysts or helminth eggs. The infection rate of intestinal parasites was 3.0% in 1995 and 2.4% in 1996. The rate was high in Africa (1995: 5.7%, 1996: 4.7%) and Asia (1995: 3.8%, 1996: 3.0%). Regarding to the species of the parasites, Giardia lamblia (17 cases), Trichuris trichiura (14) and Ascaris lumbricoides (11) were detected frequently. Additionally, 7 cases of Heterophyes heterophyes infection were found in Asia and the Middle East. The infection rate was higher in adults than that in children, and a positive relationship between the infection rate and duration of stay was observed. Among the Japanese infected with intestinal parasites, abdominal symptoms such as diarrhea or abdominal pain were common (36.8%). It is also noteworthy that 28.1% of the Japanese infected had a history of gastric diseases such as gastric ulcer. Although the infection rate of intestinal parasites among Japanese residents in developing countries was low, compared to that of the natives in the countries, the rate is still higher than that in Japanese living in the home country. It is necessary to continue preventive measures such as health education in order to eradicate intestinal parasitic infections from this group.