Analysis of lab monitoring results of flu occurring in winter and spring from 2004 to 2005 in Shiyan City

Objective This study was conducted to analyze the lab monitoring results of flu oc-cutting in winter and spring from 2004 to 2005 in Shiyan City and probe into the epideminlogical features of flu in the city of Shiyan for the formulation of effective regimen for its prevention and control．Methods Serum samples were collected from healthy population in Shiyan City from Aug．To Sept of 2004 and flu antibody was detected．5-10 nasopharyngeal swab samples were collected every week from flu-like patients in hospitals as surveillance sites for isolation of flu viruses with MDCK cells．Results It was found that type A3(H3N2)had the highest positive rate (92.00％)(GMT 76.74)，with type A1 (H1N1)having a positive rate of 35.00％(GMT 11.10)and type B of 18.00％(GMT 6.64)，being the lowest，as far as flu antibody levels in healthy popula-tion were concerned．Pathogenic surveillance showed that type B was predominant in winter and spring with 3 vilulent strains of A3(H3N2)subtype also isolated Conclusion It is scen that type A3 flu antibody level is high in population in Shiyan city，type B and A1 flu antibody level quite low The isolation rate of type B flu virus is high in the population and particular attention is to be paid to its prevention．