RESUMEN
A total of 300 stool samples collected from 213 Japanese residents of Egypt were examined microscopically. Among these samples, 39 were judged positive for heterophyid eggs. Sixty seven residents were examined repeatedly. The prevalence of heterophyid eggs revealed by the first examination samples was 8.5% (18⁄213) whereas that revealed by the second follow-up was 24% (16⁄67). The interval between the first and second examination was one year in 58 cases and 2 years in 9 cases. <br>The association of infection with the length of stay in Egypt was evident. Positivity among new residents (period of stay in Egypt ‹ 1 year) was as low as 3% (2⁄60). Positive conversion from new residents was observed in 28% (7⁄25), indicating a positive association between heterophyid infection and the length of stay in Egypt among Japanese residents of that country.