[Epidemiological characteristic of first case of locally identified A/H1N1 secondary cases caused by imported source of infection in China].
OBJECTIVE
To study the first locally identifed A/H1N1 secondary cases outbreak in China.


METHODS
Interview and field investigation were integrated to describe the whole process of transmission on each case and to illustrate the relationships between the onset of the disease and the retated factors.


RESULTS
Two contact persons appearanced fever and whose throat swabs were tested positive to H1N1 viral nucleic acid. The two had a history of contact in a short distance with the initial imported case without any protective measure in the poor air ventilation. The patients clinical situation was slight. The incubation was between 37 hours and 57 hours. No other new case was found after intervention as isolation and antisepsis were taken.


CONCLUSIONS
This event was proved to be an outbreak of local A/H1N1 secondary cases caused by the imported case. The main mode of transmission was personal contact in a short distance without protection, through air and droplet. The locus with poor air ventilation was high risk place. Contact persons should be observed seven days and tested continuously. Infectivity and pathogenicity of the A/H1N1 virus were limited and appeared weakened by generations. Patient's condition was related with persistence and frequency of contact with the infection sources. Enhancing management of contact persons, health education, early diagnose, early treatment and early insulation were effective measures of controling and prenventing the spread A/H1N1.
Yang
Zhi-Cong
ZC
Guangzhou Center for Disease Control and Prevention, Guangzhou, China.
Li
Tie-Gang
TG
Liu
Yu-Fei
YF
Wu
Xin-Wei
XW
Yuan
Jun
J
Xie
Chao-Jun
CJ
Li
Kui-Biao
KB
Jiang
Li-Yun
LY
Chen
Yi-Yun
YY
Mao
Xin-Wu
XW
Li
Hai-Lin
HL
Zhan
Liu-Hua
LH
Xiao
Xiao-Ling
XL
Liu
Jian-Ping
JP
Shen
Ji-Chuan
JC
Cai
Wen-Feng
WF
Wang
Ming
M
D002681:China / Q000453:epidemiology; D016358:Contact Tracing; D004196:Disease Outbreaks; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D007407:Interviews as Topic; D010356:Patient Isolation