 1. Appointment: After obtaining the population information from the local government, we will visit every family or household accompanied by staffs of the selected communities or villages, to obtain pediatric information of each family, explain the aim of the study, and invite the parents to take their kids to participate in the study which is held at the community of village clinic. Also we will give a notice that include the aim of the study, contents, date, and matter need attention of this survey to the parents. 