Objective To inv estigate the prevalence of influenza viruses during the period from January 2001 to June 2004.
Methods Influenzas viruses were isolated by Madin-Darby CanineKidney(MDCK)cell and embryonated eggs.Sub-types were identified by HItest.
Results During the period of January 2001 to June 2004, a total number of 17 313 throat swab specimens were collected in Guangdong, with 1 508 strains identified as influenza viruses positive.The rate of isolation was 8.71%.Of the 1 508 strains, 92 strains were influenza A-H1N1, 1138 strains were influenza A-H3N2 viruses, 278 strains were influenza Bviruses with the rates of isolation on each subtype at 6.1%, 75.4% and 18.5%, respectively.The age distributions of three types showed the peek appeared in age 5-15.The predo minant viruses were subtype of influenza A-H3N2 in 2002-2004, while influenza Bin 2001.The peak of viruses isolation occured from March to July.No influenza A-H1N1 was isolated in 2003 and 2004.Influenza A-H3N2 viruses were mainlyisolated in the epidemic period.Different from influenza A-H3N2, most of the Bviruses were isolated in winter.
Conclusion Although influenza Asubtype H1N1 and H3N2 as well as Btype viruses co-circulated in Guangdong, the activity of influenza A-H3N2 has been serious in these recenty ears.More attention should be paid to the variation of influenza Atype(H3N2)strains.
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