Abstract: 　Objective To study the relationship between cleanliness of children′s hands and diminution of Ascaris lumbricoides infection. Methods Before the study all persons positive for ascaris eggs in the preliminary survey were treated with albendazole. Hand washing habit before meal and after defecation was kept in children of experimental group, but not in the control group. Kato thick smear stool examination was done once every two months for one year to compare the new infection rates in children without ascaris infection in the two groups, and the reinfection rates in the cured negative cases were also compared between them in half a month after chemotherapy. Results All the new infection rates as well as reinfection rates of each reexamination in the experimental group were significantly lower than that of the control group ( P <0 001). Reexamination one year later showed that the ascaris infection rate of the experimental group was 35 2%, reducing by 48 5% as compared with 68 3% before the operation of the project; while ascaris infection rate of the control group was 73 7%,increasing by 78 0% as compared with 41 4% before the operation of the project. Conclusion Washing hands with toilet soap to keep hands clean can significantly reduce ascaris infection rate.

Key words: Ascaris lumbricoides, new infection rate, reinfection rate, hand washing