成都市郫都区一起学校流行性感冒暴发疫情的流行病学调查与分析

Investigation and analysis of epidemiology on the influenza breaking out in a school of Pidu District,Chengdu

目的分析一起学校流行性感冒(流感)暴发疫情的流行病学特征,探讨防控措施。方法开展现场流行病学调查与应急处置,并采集部分流感样病例咽拭子标本进行流感病毒核酸检测。结果2019年8月29日-9月12日累计发病40例,无教职工发病,发病率为2.86%(40/1398),其中男性26例、女性14例,男女比例为1.86∶1。临床表现主要以发热、咳嗽、咽痛等症状为主。发热37.4~37.9℃者10例(占25.00%),38.0~38.9℃者23例(占57.50%),39.0~40.0℃者7例(占17.50%);发病高峰分别为9月4日(7例,占17.50%)和9月8日(7例,占17.50%)。流行曲线呈人传人模式。病例分布在初一年级15个班,罹患率最高为初一年级17班,发病5例,罹患率为9.09%,占发病总数的12.50%,发病有年级和班级聚集性。采集15份流感样病例咽拭子标本,其中H3亚型流感病毒核酸阳性9份,阳性率为60.00%。结论该起事件是由H3亚型流感病毒引起的暴发疫情。病例未被及时发现和实施隔离,室内通风不良和密切接触可能是疫情扩散的原因。

Objective To analyze the epidemiological characteristics of influenza(Flu)breaking out in a school in Pidu District,and to provide a basis for the prevention and control of Flu outbreaks in the school in the future.Methods The field epidemiological investigation and emergency response were conducted,and the throat swabs from some influenza-like cases were collected for influenza virus nucleic acid testing.Results A total of 40 cases attacked from August 29 to September 12,2019 free of onset of faculty members with the incidence rate of 2.86%(40/1398)were collected.There were 26 male patients and 14 female patients with the male-to-female ratio of 1.86∶1.The clinical manifestations were dominated by fever,cough,and sore throat.There were 10 cases with fever(37.4-37.9℃)(accounting for 25.00%),23 cases with the temperature at 38.0-38.9℃(accounting for 57.50%)and 7 cases at 39.0-40.0℃(accounting for 17.50%).The morbidity peak in 4 September(7 cases,17.50%)and 8 September(7 cases,17.50%).The popular curve demonstrated the person-to-person mode.The cases were distributed in 15 classes in Grade I of junior high school.The maximum rate of attack was in 17 class in Grade I of junior high school with an attack rate of 9.09%(5 cases),accounting for 12.50%of the total number of cases.The attack was clustered by grade and class.Fifteen samples of nasopharyngeal swabs were collected for virus nucleic acid test,9 samples were positive for H3 subtype influenza virus nucleic acid with the positive rate was 60.00%.Conclusion The incident is an epidemic breaking out induced by H3 subtype influenza virus.The cases fail to be timely found and quarantined,and poor indoor ventilation and close exposure may be the reasons for the spread of the epidemic.