Objective: To analyze the results of detection on respiratory virus of influenza-like illness ( ILI ) in Beijing from June 2010 to February 2012 and understand the virus spectrum of adult influenza-like fever.
Methods: A total of 502 swabs were collected and 279 throat swabs tested for 12 respiratory viruses with multiplex reverse transcription-polymerase chain reaction (RT-PCR). And 413 swabs were tested for pH1N1 by virus isolation influenza viruses. And the data were statistically analyzed.
Results: One or two viruses were detected in 26.9% (75/279) of the samples. Influenza A virus (FLU-A) accounted for 85.3% of positive samples and 22.9% (64/279) of ILI tested. The positive rate of other viruses was less than 3.0 %. The positive rates among the following subtypes were: 2.7% (11/413) for pH1N1, 2.4% (10/413) for H3 and 6.5% (27/413) for FLU-B. FLU-A was the predominant virus during the 2010-2011 influenza season and the positive rate peaked in January 2011 in Beijing and north China. FLU-B was the primary virus during the 2011-2012 influenza season and the positive rate peaked in January and February 2012. There was a significant reduction in the incidence of ILI in 2010 and 2011 when compared with 2009. During the 2009-2012 influenza seasons, the incidence peaked in December 2009, January 2011 and January and February 2012 in Beijing.
Conclusions: Exposure to pH1N1 had no impact on typical influenza seasonal peaks. Influenza virus was the predominant virus of adult influenza-like fever cases after the pandemic period of influenza A (H1N1) 2009 and the positive rate peaked in January and February during the 2009-2012 influenza seasons.