Hygiene and play habits make children especially vulnerable to infection, and in many areas a large proportion of school-age children are infected.
卫生习惯和通常玩耍方式使儿童尤易受到感染，许多地区的大量学龄儿童已受感染。
2
The frequency of treatment is determined by the prevalence of infection or visible haematuria (in the case of urogenital schistosomiasis) in school-age children.
干预频率根据学龄儿童中的感染率或可见血尿（只适用于尿路血吸虫病）的发生率确定。
3
Objective To investigate the infection status of Norwalk virus in school canteen workers in Meixian and provide the scientific basis for Norwalk virus gastroenteritis control and prevention.