[Risk assessment of H5N1 human infection after an outbreak of avian influenza in water fowl].
OBJECTIVE
To evaluate the risk of human infection after the outbreak of avian influenza H5N1 in animals, and probe the possibility for virus transmission.


METHODS
By means of field epidemiological study, molecular epidemiology, serology and emergency surveillance, persons who had ever closely contacted with sick or dead poultry were observed. While, the RT-PCR and gene sequencing method were used to detect H5 nucleic acid from environmental swabs from 4 epidemic spots, and hemagglutination inhibition assay was also used to detect H5 antibody.


RESULTS
Of 22 environmental swabs detected from 4 epidemic spots, one was positive for H5 nucleic acid, and the homogeneity was 95.9% as compared with H5N1 virus A/China/GD01/2006 (H5N1) found in Guangzhou in 2006 by gene sequence analysis. 62 environmental swabs from live poultry stalls of food markets near epidemic spot were detected negative. Six of 68 blood samples of contacts were positive for H9 antibody, and all were negative for H5 antibody. 68 throat swabs of contacts were detected negative for H5 nucleic acid. No close contact was found abnormal after 7 days medical observation. 337 influenza-like cases were reported in emergency surveillance, and no suspicious case was found.


CONCLUSIONS
The current outbreak of H5N1 avian influenza in water fowls has not yet caused further transmission, and human avian influenza case has not been observed. It indicates that the ability of H5N1 virus to transmit to human is not strong yet, and the risk of human infection for H5N1 is still low.
Wang
Yu-lin
YL
Guangzhou Center for Disease Control and Prevention, Guangzhou 510080, China.
Liu
Yu-fei
YF
Jiang
Li-yun
LY
Liu
Yang
Y
Yang
Zhi-cong
ZC
Hao
Ai-hua
AH
Wu
Ye-jian
YJ
Li
Hai-lin
HL
Li
Tie-gang
TG
Wang
Ming
M
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D004372:Ducks; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000635:transmission; D007251:Influenza, Human / Q000453:epidemiology* / Q000635:transmission; D018570:Risk Assessment
D000914:Antibodies, Viral