于1983年5月~1985年4月,对吉林省延吉市小营乡小营村朝鲜族7岁以下儿童进行了前瞻性流行病学调查。
Epidemiological investigations on Korean children under seven in Xiaoying Village , Yanji , Jilin were made from May , 1983 to April , 1985 . It was found that there is a special characteristic and regularity when children fall ill .