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.

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 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 A Descriptive Review of Selected Nonviral Enteric Illnesses Reported in Children in Quebec between 1999 and 2006

2010 ◽  
Vol 21 (2) ◽  
pp. e92-e98 ◽  
Author(s):  
Henri Kaboré ◽  
Pascal Michel ◽  
Patrick Levallois ◽  
Pierre Déry ◽  
Pierre Payment ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Late Summer ◽  
Incidence Rates ◽  
Control Measures ◽  
Common Causes ◽  
Prevention And Control Measures ◽  
One Year ◽  
And Control ◽  
Different Sources ◽  
Geographical Characteristics

OBJECTIVE: To review the epidemiology of selected nonviral enteric illnesses reported in children in Quebec between 1999 and 2006.METHODS: Incidence rates were calculated to describe age, sex, temporal and geographical characteristics of the selected nonviral enteric cases reported in children who were between zero and four years of age. Standard descriptive methods were used to analyze the temporal and geographical distributions of the incidence rates.RESULTS: A total of 5068 cases were reported. Of these, three pathogens accounted for the majority of the infections:Giardia(32.52%),Salmonella(30.98%) andCampylobacter(30.82%).Salmonellawas most frequent in children younger than one year of age, whereas comparable incidence rates for the three pathogens were calculated for children between one and four years of age. ForGiardia, the geographical distributions showed that the highest rates were in areas with more than 100,000 inhabitants (except Montreal, Quebec); forSalmonella, the highest rates were in Montreal; and forCampylobacter,the highest rates were in areas with fewer than 10,000 inhabitants. No detectable trends were seen over the study period for the three pathogens. Seasonal summer peaks were noted forSalmonellaandCampylobacter, contrasting with late summer to early autumn peaks forGiardia.CONCLUSION: Findings suggest thatGiardia,SalmonellaandCampylobacterwere the most common causes of nonviral enteric illnesses reported in children in Quebec.Giardiacases seemed to arise from different sources and transmission routes than the other two pathogens. Characteristics specific toCampylobacterinfections in children, namely its predominance in areas with low population densities, and toSalmonellainfections, namely predominance in the Greater Montreal area, should be further investigated to better guide prevention and control measures.

scholarly journals Live Poultry Market Closure and Control of Avian Influenza A(H7N9), Shanghai, China

2014 ◽  
Vol 20 (9) ◽  
pp. 1565-1566 ◽  
Author(s):  
Yi He ◽  
Peihong Liu ◽  
Songzhe Tang ◽  
Yong Chen ◽  
Enle Pei ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Live Poultry ◽  
And Control

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 Agricultural Household Response to Avian Influenza Prevention and Control Policies

2007 ◽  
Vol 39 (2) ◽  
pp. 301-311 ◽  
Author(s):  
Robert H. Beach ◽  
Christine Poulos ◽  
Subhrendu K. Pattanayak
Keyword(s):  
Avian Influenza ◽  
Prevention And Control ◽  
Disease Risk ◽  
Control Measures ◽  
Trade Restrictions ◽  
Agricultural Household ◽  
Bird Mortality ◽  
Influenza Prevention ◽  
Prevention And Control Measures ◽  
And Control

Recent outbreaks of highly pathogenic avian influenza in Asia, Europe, and Africa have caused severe impacts on the poultry sector through bird mortality and culling, as well as resulting trade restrictions and negative demand shocks. Although poultry producers play a major role in preventing and controlling avian influenza, little research has examined the influence of their farm-level decision making on the spread of the disease. In this study, we describe farm behavior under livestock disease risk and discuss data and analyses necessary to generate sound empirical evidence to inform public avian influenza prevention and control measures.

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