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Open Forum Infect Dis. 2016 Aug 30;3(3):ofw182. eCollection 2016.
Risk Factors for Influenza A(H7N9) Disease in China, a Matched Case Control Study, October 2014 to April 2015.
Zhou L1, Ren R1, Ou J2, Kang M3, Wang X4, Havers F5, Huo X6, Liu X7, Sun Q8, He Y9, Liu B1, Wu S2, Wang Y1, Sui H1, Zhang Y10, Tang S10, Chang C10, Xiang L10, Wang D1, Zhao S1, Zhou S5, Chen T11, Xiang N1, Greene CM5, Zhang Y1, Shu Y11, Feng Z12, Li Q1.
Author information
Abstract
Background. Human infections with avian influenza A(H7N9) virus have been associated with exposure to poultry and live poultry markets (LPMs). We conducted a case-control study to identify additional and more specific risk factors. Methods. Cases were laboratory-confirmed A(H7N9) infections in persons in China reported from October 1, 2014 to April 30, 2015. Poultry workers, those with insufficient data, and those refusing participation were excluded. We matched up to 4 controls per case by sex, age, and residential community. Using conditional logistic regression, we examined associations between A(H7N9) infection and potential risk factors. Results. Eighty-five cases and 334 controls were enrolled with similar demographic characteristics. Increased risk of A(H7N9) infection was associated with the following: visiting LPMs (adjusted odds ratio [aOR], 6.3; 95% confidence interval [CI], 2.6-15.3), direct contact with live poultry in LPMs (aOR, 4.1; 95% CI, 1.1-15.6), stopping at a live poultry stall when visiting LPMs (aOR, 2.7; 95% CI, 1.1-6.9), raising backyard poultry at home (aOR, 7.7; 95% CI, 2.0-30.5), direct contact with backyard poultry (aOR, 4.9; 95% CI, 1.1-22.1), and having ≥1 chronic disease (aOR, 3.1; 95% CI, 1.5-6.5). Conclusions. Our study identified raising backyard poultry at home as a risk factor for illness with A(H7N9), suggesting the need for enhanced avian influenza surveillance in rural areas.
KEYWORDS:
avian influenza A(H7N9); case-control study; risk factor
PMID: 27704029 DOI: 10.1093/ofid/ofw182
[PubMed - in process] Free PMC Article
Risk Factors for Influenza A(H7N9) Disease in China, a Matched Case Control Study, October 2014 to April 2015.
Zhou L1, Ren R1, Ou J2, Kang M3, Wang X4, Havers F5, Huo X6, Liu X7, Sun Q8, He Y9, Liu B1, Wu S2, Wang Y1, Sui H1, Zhang Y10, Tang S10, Chang C10, Xiang L10, Wang D1, Zhao S1, Zhou S5, Chen T11, Xiang N1, Greene CM5, Zhang Y1, Shu Y11, Feng Z12, Li Q1.
Author information
Abstract
Background. Human infections with avian influenza A(H7N9) virus have been associated with exposure to poultry and live poultry markets (LPMs). We conducted a case-control study to identify additional and more specific risk factors. Methods. Cases were laboratory-confirmed A(H7N9) infections in persons in China reported from October 1, 2014 to April 30, 2015. Poultry workers, those with insufficient data, and those refusing participation were excluded. We matched up to 4 controls per case by sex, age, and residential community. Using conditional logistic regression, we examined associations between A(H7N9) infection and potential risk factors. Results. Eighty-five cases and 334 controls were enrolled with similar demographic characteristics. Increased risk of A(H7N9) infection was associated with the following: visiting LPMs (adjusted odds ratio [aOR], 6.3; 95% confidence interval [CI], 2.6-15.3), direct contact with live poultry in LPMs (aOR, 4.1; 95% CI, 1.1-15.6), stopping at a live poultry stall when visiting LPMs (aOR, 2.7; 95% CI, 1.1-6.9), raising backyard poultry at home (aOR, 7.7; 95% CI, 2.0-30.5), direct contact with backyard poultry (aOR, 4.9; 95% CI, 1.1-22.1), and having ≥1 chronic disease (aOR, 3.1; 95% CI, 1.5-6.5). Conclusions. Our study identified raising backyard poultry at home as a risk factor for illness with A(H7N9), suggesting the need for enhanced avian influenza surveillance in rural areas.
KEYWORDS:
avian influenza A(H7N9); case-control study; risk factor
PMID: 27704029 DOI: 10.1093/ofid/ofw182
[PubMed - in process] Free PMC Article