Epidemiological and experimental studies on pinworm infestation in Korea
Pinworm (Enterobius vermicularis) infestation in present day Korea has become one of nationwide problems. Chyu and Kim(1959), Seo and Lim(1963) and Lee at al. (1964) reported the incidence of pinworm infestation in Korea to be about 20 percent.
It may be worthwhile to study epidemiologically what is the main reason for such a high incidence both in rural and urban areas. The author made an investigation on the incidence of pinworm infestation for 72 families of 207 (male 128, female 79)
rural inhabitants in Kyunggi Province, 115 families of 502 (male 297, female 205) upper class inhabitants of Seoul, 58 families of 296 (male 140, female 156) suburban inhabitants of Seoul and 799 (male 446, female 353) orphans accommodated in 14 orphanages in Seoul and Kyunggi Province. Epidemiological factors of pinworm
infestation as well as biological characters of the ova of Enterobius vermicularis were also studied.
The result are summarized as follows:
1. Familial incidence in Seoul and rural areas was 48.6 percent in average.
2. 38.2 percent of suburban inhabitants of Seoul and 30.9 percent of rural inhabitants were infested with pinworm, and the incidence for the children of orphanages was the highest with 54.2 percent while 13.3 percent of upper class of Seoul was the lowest.
3. There was no noticeable difference of incidence between male and female for the upper class of Seoul and rural area, but for the suburban area of Seoul it was slightly higher in female.
4. There was no relationship between the family size and the incidence.
5. Children infested with pinworm seemed to play an important factor for the high incidence in individual family.
6. Number of rooms in a family and number of persons in each room seemed to have an influence on pinworm infestation.
7. The ova were found in 16.7 percent out of 90 dust samples collected from the living rooms of Seoul suburbs and 4.5 percent of them appeared in matured condition.
8. The immature ova required 24 hours to develop to matured stage in Spring, and 18 days were needed in Automn at the similar level of room temperature.
9. The higher the temperature, the sooner the ova developed to a matured form, taking 45 minutes at 50℃, 4 hours at 37℃, 5 hours at 35℃, 20 hours at 30℃, 22 hours at 24℃ and 450 hours (about 18 days) at 18℃.
10. 30.6 percent of ova were still alive after being kept in 4±2℃ for 10 days and larva in egg shell was motile for 48 hours in iced water.
11. In tap water under room temperature the ova generally become matured state in 3 days and gradually destroyed following automatic excystation.
12. The ova survived for 24 hours in various concentrations of detergents with the survival rate of 40 percent in 2% cleaning soap, 30 percent in Ⅰ Ⅳ solution of sodium hydroxide and more than 50
13. The ova were completely destroyed within 48 hours in 30% solution of sodium of them survived for 24 hours in vinegar and sauce did not have any ovicidal action. 10gm% of look, garlic, red pepper and mustard showed appreciable ovicidal effect during the period of 4 days.