论文部分内容阅读
一、情况介绍在美国,每年都发生病毒性流感,但是在发病率和地理分布方面却有很大的变化。感染了流感,可能不表现出症状;也可能发生由轻微的上呼吸道感染症状到肺炎和死亡的一系列表现。虽然甲、乙型流感占全部呼吸道疾病很小比例,但在儿童和成人中引起急性呼吸道疾病周期性的广泛爆发是独一无二的。流感大流行经常发生超标死亡数,如1968—1982年流感流行期间,美国估计多死亡二十多万人。在这期间,流感超标死亡病例主要是由甲型流感病毒引起的。而乙型流
I. Introduction In the United States, viral influenza occurs every year, but there is a great change in the incidence and geographical distribution. Infected with flu may not show symptoms; a series of signs of pneumonia and death may also occur from mild symptoms of upper respiratory tract infection. Although influenza A and B account for a small proportion of all respiratory diseases, the cyclical widespread outbreak of acute respiratory diseases in children and adults is unique. Often, the number of deaths from influenza pandemics exceeds the number of deaths. For example, during the 1968-1982 influenza epidemic, the United States estimated that more than 200,000 people died of the disease. During this period, the number of flu deaths caused by influenza A was mainly caused by the influenza A virus. The B-type flow