关于长潜伏期间日疟,十三年前我们曾进行过一些研究,提示本地区有这种间日疟的存在。近几年,我区各县普遍反映在上半年患疟疾的病人中,一年内无疟史的发病者较多,约占40～50％,甚至90％。为进一步查明目前长潜伏期间日疟的发病情况,提供制订防治对策的依据,我们于1973年6月～1974年6月,对这个问题再次进行了研究,现将观察结果报告如下。 About vivax malaria during the long incubation period, we conducted some studies 13 years ago, suggesting the existence of such vivax in the region. In recent years, counties in our district generally reflect the incidence of malaria in the first half of the year, with no incidence of malaria in one year, accounting for 40 to 50% or even 90%. In order to further identify the incidence of vivax malaria during the long incubation period and provide a basis for the development of control strategies, we conducted a further study on this issue from June 1973 to June 1974 and report the observations as follows.