Enterobius vermicularis egg positive rates in primary school children in Gangwon-do (Province), Korea
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Abstract
A survey of the infection rate of Enterobius vermicularis among students in 4 primary schools located in Gangwon-do (Province) was done from May to June 2001. Among the 398 examinees, 39 (9.8%) were infected with E. vermicularis demonstrated by the adhesive cellotape anal swab method. The infection rates ranged from 8.3% to 11.8% among the four schools. The infection rate of males and females was 10.7% and 7,7% respectively. The first grade students showed the highest infection rate, 28.7%. The confirmed cases were treated with albendazole three times at an interval of 15 days. We were able to confirm that E. vermicularis infection is still prevalent among students in Gangwon-do, Korea.
In Korea, Enterobiasis shows the highest infection rate among the nematode infections, and a high infection rate in children living or studying in a large group, such as schools, kindergartens, and orphanages (Lee et al., 1996). Enterobius vermicularis causes symptoms including neurosis, anal itching, vomiting, sleeping disorder, and salphingitis (Beaver et al., 1984; Chung et al., 1997). Several conditions such as complexity of diagnosis and treatment, short duration of life cycle, and high infectivity make the control of the disease difficult. Recently, high infection rates were reported in kindergartens (7.8%) and primary schools, (14.8%) in Korea (Lee et al., 2000; Yoon et al., 2000). The infection rate of E. vermicularis in Gangwon-do was 15.3% in 1991 (Kim et al., 1991) and 17.5% in 1997 (Yang et al., 1997). Two species in the genus Enterobius were found in Wonju-si (city), Gangwon-do. Ahn et al. (1992) reported E. gregorii made up 23.2% of the examined worms in Wonju.
This survey was conducted to identify the infection rate of E. vermicularis in primary school children in Gangwon-do. We examined all the students attending four schools, 397 students altogether. One of the four schools was located in the small town of Goseong-gun (county), and the other three schools were located in the rural area around Wonju. The survey was done by adhesive cellotape anal swab methods. The infection rate in the four schools was 8.3%, 8.5%, 10.4%, and 11.8% respectively. First grade students showed the highest infection rate (28.7%) and the lowest infection rate was in the fifth grade (2.6%). The mean infection rate of the examinees was 9.8%. All of the infected students were treated with 400 mg albendazole twice at three-week interval. It is well known that adhesive cellotape anal swab methods show about a 50% egg detection rate in the first examination (Kim et al., 1991). This survey was executed as a one-time adhesive cellotape anal swab method, so it is presumed that there were undetected students. Goseong-gun is far from Wonju, but the infection rate in Goesong-gun was slightly different from that in Wonju. This study was done by a random sampling method. Thus similar infection rates of E. vermicularis are suspected in other schools in Gangwon-do and an expanded survey of schools in other areas is required.
Effective methods of E. vermicularis control in primary schools are an exact diagnosis and treatment to prevent infection to other students. A variety of infection routes of the worm to the student, including retrograde infection, air borne infection, and anus to mouth infection, maintain the high infection state. It is difficult for primary schools to control the E. vermicularis by themselves. Endeavors by public health and educational institutions could reduce the infection rate of E. vermicularis in Gangwon-do.