我国流感监测（1990～1993）

Influenza Surveillance in China (1990-1993)

３年多监测结果表明，１９９０年１０月～１９９３年３月流感病毒在我国的活动特点，具有地区性差异。在３年多监测时间内，我国共发生过２次流感爆发流行，分别发生在１９９１～１９９２和１９９２～１９９３年流感流行季节，同时均发生在北方，而南方处于平静状态。其次在北方流感病毒活动具有严格的季节性，每年活动高峰均在冬季，而在南方见不到有严格的季节性。疫情上具有局限性，受主要侵袭的为青少年和婴幼儿，故发生爆发流行的主要集中在大、中、小学校和托幼单位。病原上表现出，乙型病毒株活动增强而甲型病毒株活动相对减弱并表现出不同亚型病毒株间交替占优。同时还表现出抗原性的多样性，无论Ｈ３Ｎ２亚型病毒株还是乙型病毒，在人群中可同时流行着两种以上抗原性不同的病毒株，哪个为主要流行株往往一时难判断。我们的研究结果指出，流感监测光靠疫情显然不够，必须同时要有病原监测。而且证实了流感监测在我国南北方具有同等的重要性。

The results of influenza surveillance obtainted in more than three years indicated that during October 1990-March 1993, two influenza local outbreaks occurred in China, in 1991-1992 and 1992-1993 epidemic seasons, respectively and both occurred in North China, but in South the influenza activities were in static state during the same period. There was obvious difference in influenza activities between North and South China. The influenza virus activities were affected obviously by season in North, So the peaks of influenza virus activities were all in winter season, but the effect of season on influenza activities was not remarkable in South. The distribution of cases in different age groups caused by current strains of influenza viruses was different. Although all age groups were affected, but the adolescents, children and infant were mainly affected in the outbreaks. Therefore, all outbreaks occurred mainly in high, middle and primary schools, and nursenes. The characteristics of activities of different influenza viruses were different. The activities of influenza B viruses increased remarkably, but those of influenza A viruses decreased and the by predominant strain was replaced by others in different years. The antigenic diversity of influenza virus was found. There were two or more different antigencities in H3N2 virus as well as in type B strains cocirculated in human population at the same time. It is always too difficult to determine immediately which strain has epidemic significance.The present paper pointed out that only recording the number of acute respiratory diseases in influenza surveillance was not enough, the viral surveillance must also be carried out. The results demonstrated that influenza surveillances in both North and in South China are equally important.