Case-control study of risk factors for avian influenza A (H5N1) disease, Hong Kong, 1997.
In May 1997, a 3-year-old boy in Hong Kong died of a respiratory illness related to influenza A (H5N1) virus infection, the first known human case of disease from this virus. An additional 17 cases followed in November and December. A case-control study of 15 of these patients hospitalized for influenza A (H5N1) disease was conducted using controls matched by age, sex, and neighborhood to determine risk factors for disease. Exposure to live poultry (by visiting either a retail poultry stall or a market selling live poultry) in the week before illness began was significantly associated with H5N1 disease (64% of cases vs. 29% of controls, odds ratio, 4.5, P=.045). By contrast, travel, eating or preparing poultry products, recent exposure to persons with respiratory illness, including persons with known influenza A (H5N1) infection, were not associated with H5N1 disease.
Epidemic Intelligence Service, Epidemiology Program Office, Division of Applied Public Health Training, National Center for Infectious Diseases, Centers for Disease Control, Atlanta, GA 30033
A W
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Mounts
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H
Kwong
H S
HS
Izurieta
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Y
Ho
T
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Au
M
M
Lee
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C
Buxton Bridges
S W
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Williams
K H
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Mak
J M
JM
Katz
W W
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Thompson
N J
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Cox
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Fukuda
D000293:Adolescent; D000328:Adult; D000818:Animals; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006723:Hong Kong; D006801:Humans; D007223:Infant; D053124:Influenza A Virus, H5N1 Subtype; D009980:Influenza A virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000209:etiology* / Q000821:virology; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D011200:Poultry; D012307:Risk Factors