Factors influencing virus isolation during sample collection from influenza-like illness cases in Shiyan, Hubei

Objective To understand the factors influencing the virus isolation during sample collection from influenza like illness(ILI) cases in Shiyan, Hubei province, and provide evidence for the improvement of influenza etiological surveillance. Methods The analysis was conducted on the quality of the clinical samples of ILI cases sent by 2 sentinel hospitals in Shiyan between January and October 2012. Results The quality of the samples collected from children was better than that from adults, the positive rate of the samples collected within 1-2 days after onset was highest, the difference in the positive rate of the samples collected at different days had statistical significance(χ2=21.145, P=0.001). The samples stored at-20℃ for less than 4 days had a positive rate of>60%. Conclusion The quality of clinical samples and store and transport conditions are the important factors related to the success of influenza virus isolation.