[Analysis on surveillance of influenza in Tianshui prefecture from 2005 to 2008].
OBJECTIVE
To observe epidemic status and the types of the influenza virus, to analyse influenza epidemic trends in Tianshui City, and to provide basis for influenza prevention and control.


METHODS
Throat swab specimens of influenza cases in pilot hospitals and area of influenza-like a typical outbreak in Nov. 2005-Oct. 2008 was tested by chicken embryo and MDCK cells. The identification of the isolates was carried out by hemagglutination and hemagglutination inhibition test. The separation of strains were sent to the National Influenza Center to conduct a review appraisal.


RESULTS
1819 throat swab specimens of influenza-like were collected and 247 were isolated. Isolation rate was 13.58%. There were 36 strains (14.57%) of A (H1N1) subtype, 75 strains (30.36%) of A (H3N2) subtype and 136 (Victoria department 121, Yamagata department 15) strain (55.06%) of B subtype.


CONCLUSIONS
There were three epidemic types of influenza virus types-A (H1N1), A (H3N2) and B in Tianshui. Virus were epidemic at the same time or alternating at different intensity in different years. Outbreaks of influenza have occurred in rural primary and secondary schools, and B subtype was dominating.
Fan
Duo-zhi
DZ
Tianshui Municipal Center for Disease Control and Prevention, Tianshui 741000, Gansu, China.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D002648:Child; D002675:Child, Preschool; D002681:China; D004196:Disease Outbreaks; D004285:Dogs; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000276:immunology / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000276:immunology / Q000302:isolation & purification*; D009981:Influenza B virus / Q000145:classification / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011159:Population Surveillance; D055815:Young Adult