scholarly journals Live Poultry Market Closure and Avian Influenza A (H7N9) infection in cities of China, 2013-2017: An ecological study

2020 ◽  
Author(s):  
Ying Chen ◽  
Jian Cheng ◽  
Zhiwei Xu ◽  
Wenbiao Hu ◽  
Jiahai Lu
Keyword(s):  
Avian Influenza ◽  
Risk Reduction ◽  
Influenza A ◽  
Reduction Rate ◽  
Dominant Factor ◽  
Effective Measure ◽  
Partial Closure ◽  
Live Poultry ◽  
H7n9 Infection ◽  
The Impact

Abstract Background Previous studies have proven that the closure of live poultry markets (LPMs) was an effective intervention to reduce human risk of avian influenza A (H7N9) infection, but evidence is limited on the impact of scale and duration of LPMs closure on the transmission of H7N9. Method Five cities (i.e., Shanghai, Suzhou, Shenzhen, Guangzhou and Hangzhou) with the largest number of H7N9 cases in mainland China from 2013-2017 were selected in this study. Data on laboratory-confirmed H7N9 human cases in those five cities were obtained from the Chinese National Influenza Centre. The detailed information of LPMs closure (i.e., area and duration) was obtained from the Ministry of Agriculture. We used a generalized linear model with a Poisson link to estimate the effect of LPMs closure, reported as relative risk reduction (RRR). We used classification and regression trees (CARTs) to select and quantify the dominant factor of H7N9 infection. Results All five cities implemented the LPMs closure, and the risk of H7N9 infection decreased significantly after LPMs closure with RRR ranging from 0.80-0.93. Respectively, a long-term LPMs closure for 10-13 weeks elicited a sustained and highly significant risk reduction of H7N9 infection (RRR = 0.98). Short-time LPMs closure with 2 weeks in every epidemic did not reduce the risk of H7N9 infection (p>0.05). Partially closed LPMs in some suburbs contributed only 35% for reduction rate (RRR=0.35). Shenzhen implemented partial closure for first 3 epidemics (p>0.05) and all closure in the latest 2 epidemic waves (RRR=0.64). Conclusion Our findings suggest that LPMs all closure in whole city can be a highly effective measure comparing with partial closure (i.e. only urban closure, suburb and country remain open). Extend the duration of closure and consider permanently closing the LPMs will help improve the control effect. The effect of LPMs closure is greater than that of meteorology on H7N9 transmission.

scholarly journals Live Poultry Market Closure and Avian Influenza A (H7N9) infection in cities of China, 2013-2017: An ecological study

2020 ◽  
Author(s):  
Ying Chen ◽  
Jian Cheng ◽  
Zhiwei Xu ◽  
Wenbiao Hu ◽  
Jiahai Lu
Keyword(s):  
Avian Influenza ◽  
Risk Reduction ◽  
Influenza A ◽  
Reduction Rate ◽  
Dominant Factor ◽  
Effective Measure ◽  
Partial Closure ◽  
Live Poultry ◽  
H7n9 Infection ◽  
The Impact

Abstract Background Previous studies have proven that the closure of live poultry markets (LPMs) was an effective intervention to reduce human risk of avian influenza A (H7N9) infection, but evidence is limited on the impact of scale and duration of LPMs closure on the transmission of H7N9. Method Five cities (i.e., Shanghai, Suzhou, Shenzhen, Guangzhou and Hangzhou) with the largest number of H7N9 cases in mainland China from 2013-2017 were selected in this study. Data on laboratory-confirmed H7N9 human cases in those five cities were obtained from the Chinese National Influenza Centre. The detailed information of LPMs closure (i.e., area and duration) was obtained from the Ministry of Agriculture. We used a generalized linear model with a Poisson link to estimate the effect of LPMs closure, reported as relative risk reduction (RRR). We used classification and regression trees (CARTs) to select and quantify the dominant factor of H7N9 infection. Results All five cities implemented the LPMs closure, and the risk of H7N9 infection decreased significantly after LPMs closure with RRR ranging from 0.80-0.93. Respectively, a long-term LPMs closure for 10-13 weeks elicited a sustained and highly significant risk reduction of H7N9 infection (RRR = 0.98). Short-time LPMs closure with 2 weeks in every epidemic did not reduce the risk of H7N9 infection (p>0.05). Partially closed LPMs in some suburbs contributed only 35% for reduction rate (RRR=0.35). Shenzhen implemented partial closure for first 3 epidemics (p>0.05) and all closure in the latest 2 epidemic waves (RRR=0.64). Conclusion Our findings suggest that LPMs all closure in whole city can be a highly effective measure comparing with partial closure (i.e. only urban closure, suburb and country remain open). Extend the duration of closure and consider permanently closing the LPMs will help improve the control effect. The effect of LPMs closure is greater than that of meteorology on H7N9 transmission.

scholarly journals Live Poultry Market Closure and Avian Influenza A (H7N9) infection in cities of China, 2013-2017: An ecological study

2020 ◽  
Author(s):  
Ying Chen ◽  
Jian Cheng ◽  
Zhiwei Xu ◽  
Wenbiao Hu ◽  
Jiahai Lu
Keyword(s):  
Avian Influenza ◽  
Risk Reduction ◽  
Influenza A ◽  
Reduction Rate ◽  
Dominant Factor ◽  
Effective Measure ◽  
Partial Closure ◽  
Live Poultry ◽  
H7n9 Infection ◽  
The Impact

Abstract Background: Previous studies have proven that the closure of live poultry markets (LPMs) was an effective intervention to reduce human risk of avian influenza A (H7N9) infection, but evidence is limited on the impact of scale and duration of LPMs closure on the transmission of H7N9. Method: Five cities (i.e., Shanghai, Suzhou, Shenzhen, Guangzhou and Hangzhou) with the largest number of H7N9 cases in mainland China from 2013 to 2017 were selected in this study. Data on laboratory-confirmed H7N9 human cases in those five cities were obtained from the Chinese National Influenza Centre. The detailed information of LPMs closure (i.e., area and duration) was obtained from the Ministry of Agriculture. We used a generalized linear model with a Poisson link to estimate the effect of LPMs closure, reported as relative risk reduction (RRR). We used classification and regression trees (CARTs) model to select and quantify the dominant factor of H7N9 infection. Results: All five cities implemented the LPMs closure, and the risk of H7N9 infection decreased significantly after LPMs closure with RRR ranging from 0.80 to 0.93. Respectively, a long-term LPMs closure for 10-13 weeks elicited a sustained and highly significant risk reduction of H7N9 infection (RRR = 0.98). Short-time LPMs closure with 2 weeks in every epidemic did not reduce the risk of H7N9 infection (p>0.05). Partially closed LPMs in some suburbs contributed only 35% for reduction rate (RRR=0.35). Shenzhen implemented partial closure for first 3 epidemics (p>0.05) and all closure in the latest 2 epidemic waves (RRR=0.64). Conclusion: Our findings suggest that LPMs all closure in whole city can be a highly effective measure comparing with partial closure (i.e. only urban closure, suburb and rural remain open). Extend the duration of closure and consider permanently closing the LPMs will help improve the control effect. The effect of LPMs closure seems greater than that of meteorology on H7N9 transmission.

scholarly journals Predicting the risk of avian influenza A H7N9 infection in live-poultry markets across Asia

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Marius Gilbert ◽  
Nick Golding ◽  
Hang Zhou ◽  
G. R. William Wint ◽  
Timothy P. Robinson ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Live Poultry ◽  
H7n9 Infection ◽  
Live Poultry Markets

scholarly journals Risk Factors for Influenza A(H7N9) Disease in China, a Matched Case Control Study, October 2014 to April 2015

2016 ◽  
Vol 3 (3) ◽  
Author(s):  
Lei Zhou ◽  
Ruiqi Ren ◽  
Jianming Ou ◽  
Min Kang ◽  
Xiaoxiao Wang ◽  
...  
Keyword(s):  
Risk Factors ◽  
Avian Influenza ◽  
Direct Contact ◽  
Influenza A ◽  
Case Control Study ◽  
Case Control ◽  
Backyard Poultry ◽  
Live Poultry ◽  
H7n9 Infection ◽  
Control Study

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.

scholarly journals The Impact of the Closure of the Live Poultry Market due to COVID-19 on the Avian Influenza Virus in Nanchang, Jiangxi Province, China

2021 ◽  
Author(s):  
Jin Guo ◽  
Wentao Song ◽  
Xiansheng Ni ◽  
Kun Zhou ◽  
Jingwen Wu ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Jiangxi Province ◽  
Detection Rates ◽  
Before And After ◽  
Avian Influenza A Virus ◽  
Positive Rate ◽  
Live Poultry ◽  
The Impact

This article aims to understand the changes in the detection rates of H5, H7, and H9 subtypes of avian influenza viruses (AIVs) in the live poultry markets (LPMs) in Nanchang City, Jiangxi Province, before and after the outbreak of the COVID-19. From 2019 to 2020, we monitored the LPM and collected specimens, using real-time reverse transcription polymerase chain reaction technology to detect the nucleic acid of type A AIV in the samples. The H5, H7, and H9 subtypes of influenza viruses were further classified for positive results. We analyzed 1,959 samples before and after the outbreak and found that the positive rates of avian influenza A virus (39.69%) and H9 subtype (30.66%) after the outbreak were significantly higher than before the outbreak (26.84% and 20.90%, respectively; P < 0.001). In various LPMs, the positive rate of H9 subtypes has increased significantly (P ≤ 0.001). Positive rates of the H9 subtype in duck, fecal, daub, and sewage samples, but not chicken samples, have increased to varying degrees. This study shows that additional measures are needed to strengthen the control of AIVs now that LPMs have reopened after the relaxing of COVID-19–related restrictions.

scholarly journals Interventions in Live Poultry Markets for the Control of Avian Influenza: A Systematic Review and Meta-analysis

2019 ◽  
Author(s):  
Naiyang Shi ◽  
Jinxin Huang ◽  
Xuefeng Zhang ◽  
Changjun Bao ◽  
Na Yue ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Meta Analysis ◽  
Qualitative Evaluation ◽  
Detection Rates ◽  
Live Poultry ◽  
Human Infections ◽  
Control And Management ◽  
The Impact ◽  
Live Poultry Markets

Abstract Background This review aimed to provide constructive suggestions for the control and management of avian influenza through quantitative and qualitative evaluation of the impact of different live poultry market (LPM) interventions. Methods Both English and Chinese language databases were searched for articles that were published on or before 9 November 2018. After extraction and assessment of the included literature, Stata14.0 was applied to perform a meta-analysis to explore the impacts of LPM interventions. Results A total of 19 studies were identified. In total, 224 human, 3550 poultry, and 13 773 environment samples were collected before the intervention; 181 people, 4519 poultry, and 9562 environments were sampled after LPM interventions. Avian influenza virus (AIV) detection rates in the LPM environment (odds ratio [OR], 0.393; 95% confidence interval [CI], 0.262–0.589) and the incidence of AIV infection (OR, 0.045; 95% CI, 0.025–0.079) were significantly lower after LPM interventions, while interventions were not significantly effective in reducing AIV detection in poultry samples (OR, 0.803; 95% CI, 0.403–1.597). Conclusions LPM interventions can reduce AIV human infections and the detection rate of AIV in market environments.

scholarly journals Changing geographic patterns and risk factors for avian influenza A(H7N9) infection in China

2017 ◽  
Author(s):  
Jean Artois ◽  
Xiling Wang ◽  
Hui Jiang ◽  
Ying Qin ◽  
Morgan Pearcy ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Range Expansion ◽  
Influenza A ◽  
Northern China ◽  
Incidence Rates ◽  
Control Measures ◽  
Live Poultry ◽  
H7n9 Infection ◽  
Prevention And Control Measures ◽  
And Control

AbstractThe 5th epidemic wave in 2016-2017 of avian influenza A(H7N9) virus in China caused more human cases than any previous waves but the factors that may explain the recent range expansion and surge in incidence remain unknown. We investigated the effect of anthropogenic, poultry and wetland information and of market closures on all epidemic waves (1-5). Poultry predictor variables recently became much more important than before, supporting the assumption of much wider H7N9 transmission in the chicken reservoir, that could be linked to increases in pathogenicity. We show that the future range expansion of H7N9 to northern China may translate into a higher risk of coinciding peaks with those of seasonal influenza, leading to a higher risk of reassortments. Live-poultry market closures are showed to be effective in reducing the local incidence rates of H7N9 human cases, but should be paired with other prevention and control measures to prevent transmission.

Case-control study of risk factors for human infection with avian influenza A(H7N9) virus in Shanghai, China, 2013

2014 ◽  
Vol 143 (9) ◽  
pp. 1826-1832 ◽  
Author(s):  
J. LI ◽  
J. CHEN ◽  
G. YANG ◽  
Y. X. ZHENG ◽  
S. H. MAO ◽  
...  
Keyword(s):  
Risk Factors ◽  
Avian Influenza ◽  
Influenza A ◽  
Case Control Study ◽  
Case Control ◽  
Human Infection ◽  
H7n9 Virus ◽  
Live Poultry ◽  
H7n9 Infection ◽  
Control Study

SUMMARYThe first human infection with avian influenza A(H7N9) virus was reported in Shanghai, China in March 2013. An additional 32 cases of human H7N9 infection were identified in the following months from March to April 2013 in Shanghai. Here we conducted a case-control study of the patients with H7N9 infection (n = 25) using controls matched by age, sex, and residence to determine risk factors for H7N9 infection. Our findings suggest that chronic disease and frequency of visiting a live poultry market (>10 times, or 1–9 times during the 2 weeks before illness onset) were likely to be significantly associated with H7N9 infection, with the odds ratios being 4·07 [95% confidence interval (CI) 1·32–12·56], 10·61 (95% CI 1·85–60·74), and 3·76 (95% CI 1·31–10·79), respectively. Effective strategies for live poultry market control should be reinforced and ongoing education of the public is warranted to promote behavioural changes that can help to eliminate direct or indirect contact with influenza A(H7N9) virus.

scholarly journals Avian Influenza A (H7N9) Model Based on Poultry Transport Network in China

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Juping Zhang ◽  
Wenjun Jing ◽  
Wenyi Zhang ◽  
Zhen Jin
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Suitable Condition ◽  
Threshold Value ◽  
Transport Network ◽  
Transmission Model ◽  
Poultry Farm ◽  
Wholesale Market ◽  
Backyard Poultry ◽  
Live Poultry

In order to analyze the spread of avian influenza A (H7N9), we construct an avian influenza transmission model from poultry (including poultry farm, backyard poultry farm, live-poultry wholesale market, and wet market) to human according to poultry transport network. We obtain the threshold value for the prevalence of avian influenza A (H7N9) and also give the existence and number of the boundary equilibria and endemic equilibria in different conditions. We can see that poultry transport network plays an important role in controlling avian influenza A (H7N9). Finally, numerical simulations are presented to illustrate the effects of poultry in different places on avian influenza. In order to reduce human infections in China, our results suggest that closing the retail live-poultry market or preventing the poultry of backyard poultry farm into the live-poultry market is feasible in a suitable condition.

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