一、概况 1961年秋冬,安徽省颍上县发生流行性出血热(肾型)。在62万人口中发现1,314名病例,全年发病率达2.11‰。疫情之重,范围之广,在医学文献中尚未见报道。颍上县临近淮河,病例集中在沿淮河的洼地。地势愈低,愈靠近洼地,病例数愈多(图1)。垂岗区地势最低,离洼地最近;在31,301人中发现684例,发病率达21.8‰,为全县之冠。垂 First, the general situation In autumn and winter of 1961, epidemic hemorrhagic fever (renal type) occurred in Yingshang County, Anhui Province. In the population of 620,000, 1,314 cases were found, with an annual incidence of 2.11 ‰. The heavy and wide range of outbreaks has not been reported in the medical literature yet. Yingshang County near the Huaihe River, the case concentrated in the depression along the Huaihe River. The lower the terrain, the more the depression, the more the number of cases (Figure 1). Danggang area has the lowest terrain and is near the depressions; 684 cases were found in 31,301 people, with a incidence rate of 21.8%, ranking first in the county. Vertical