RESUMO
Objective To explore the epidemics of influenza viruses in Guangzhou area from 1998 to 2003. Methods The specimens for viral isolation were taken with swabs from children's throats and the material was inoculated into the MDCK cells and were incubated at 33 ℃ The supernatant of MDCK cells culture was tested with hemagglutination test. Results Influenza viruses were isolated from 264 of 3444 children; total positive rate of influenza virus isolation was 7.6%. The positive rate of influenza viruses was 16.8% in 1998; the prevailing strain of influenza viruses was H3N2. The influenza viruses isolation rate was 7.4% in 1999;the positive rate was 8.4% ; HIN1 occurred in 2000, the positive rate was 3.8%. H3N2 did not occur in 2001; the positive rate was 7.3% ; influenza B viruses was the prevailing strain in 2002; the positive rate was 1.7% in 2003. Influenza B viruses was Yamagata like strain from 1998 to 2001, Victoria like strain from 2002 to 2003. H9N2 avian influenza virus was isolated from a child. Conclusions Influenza was prevalent in Guangzhou in 1998, but not prevalent from 1999 to 2003. Most of influenza B viruses were Yamagata strain. There were cases avian influenza caused by H9N2 in 1999.