Survey of influenza B outbreak in a middle school

OBJECTIVE To analysis the causes and characteristics of influenza outbreak in a middle school so as to provide reference and basis for prevention and control of school influenza. METHODS The survey was developed combining field epidemiological survey and laboratory testing. RESULTS This epidemic situation lasted 12 days. The epidemic spread to 3 grades and 5 classes with obvious class aggregation. 61 students in all the school had influenza with an incident rate of 3.21%. The isolated virus was influenza virus type B. CONCLUSION The epidemic situation is caused by the outbreak of influenza B virus. The primary causes of outbreak includes that the school morning examination system is not implemented strictly , patients are not found, isolated and treated promptly and inadequate indoor ventilation.