Closure of live bird markets leads to the spread of H7N9 influenza in China

Li, Yin; Wang, Youming; Shen, Chaojian; Huang, Jun; Kang, Jian; Huang, Biao; Guo, Fei; Edwards, John

doi:10.1371/journal.pone.0208884

Cited by 25 publications

(24 citation statements)

References 19 publications

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“…Another reason could be price changes in neighbouring provinces, which may have provided incentives for traders to collect pigs from more distant counties. A study on live poultry movement in China reported that when the price of poultry changed in neighbouring provinces, the direction of movement of live poultry also changed accordingly (Li et al, ). It is worth noting that the increased supply counties in this network resulted in a change in the structure of the local market trade network.…”

Section: Discussionmentioning

confidence: 99%

Pig trade networks through live pig markets in Guangdong Province, China

Huang

Shen

et al. 2020

Transbound Emerg Dis

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This study used social network analysis to investigate the indirect contact network between counties through the movement of live pigs through four wholesale live pig markets in Guangdong Province, China. All 14,118 trade records for January and June 2016 were collected from the markets and the patterns of pig trade in these markets analysed. Maps were developed to show the movement pathways. Evaluating the network between source counties was the primary objective of this study. A 1-mode network was developed. Characteristics of the trading network were explored, and the degree, betweenness and closeness were calculated for each source county.Models were developed to compare the impacts of different disease control strategies on the potential magnitude of an epidemic spreading through this network. The results show that pigs from 151 counties were delivered to the four wholesale live pig markets in January and/or June 2016. More batches (truckloads of pigs sourced from one or more piggeries) were traded in these markets in January (8,001) than in June 2016 (6,117). The pigs were predominantly sourced from counties inside Guangdong Province (90%), along with counties in Hunan, Guangxi, Jiangxi, Fujian and Henan provinces. The major source counties (46 in total) contributed 94% of the total batches during the two-month study period. Pigs were sourced from piggeries located 10 to 1,417 km from the markets. The distribution of the nodes' degrees in both January and June indicates a free-scale network property, and the network in January had a higher clustering coefficient (0.54 vs. 0.39) and a shorter average pathway length (1.91 vs. 2.06) than that in June. The most connected counties of the network were in the central, northern and western regions of Guangdong Province.Compared with randomly removing counties from the network, eliminating counties with higher betweenness, degree or closeness resulted in a greater reduction of the magnitude of a potential epidemic. The findings of this study can be used to inform targeted control interventions for disease spread through this live pig market trade network in south China. K E Y W O R D Sanimal movement, disease control, new intervention strategies, social network, veterinary epidemiology 2 | LI et aL.

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Section: Discussionmentioning

confidence: 99%

Pig trade networks through live pig markets in Guangdong Province, China

Huang

Shen

et al. 2020

Transbound Emerg Dis

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“…Closing LBMs appears to be an effective approach for eradicating or reducing H7N9 infections in humans 32 . However, a recent study presented www.nature.com/scientificreports www.nature.com/scientificreports/ evidence that the closure of LBMs in early waves of H7N9 influenza had resulted in expansion of H7N9 infection to uninfected areas 20 . This implies closing LBMs is a long-term strategy that needs to be further evaluated.…”

Section: Discussionmentioning

confidence: 99%

“…However, this may not be favorable to poultry enterprises or individual households due to the associated financial costs. Reactive closure of LBMs may facilitate further dissemination through the opening of unregistered LBMs or illegal poultry movements 20 .…”

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confidence: 99%

Geographical variation in the risk of H7N9 human infections in China: implications for risk-based surveillance

Zhou

Gao

Wang

et al. 2020

Sci Rep

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The influenza A (H7N9) subtype remains a public health problem in China affecting individuals in contact with live poultry, particularly at live bird markets. Despite enhanced surveillance and biosecurity at LBMs H7N9 viruses are now more widespread in China. This study aims to quantify the temporal relationship between poultry surveillance results and the onset of human H7N9 infections during 2013-2017 and to estimate risk factors associated with geographical risk of H7N9 human infections in counties in Southeast China. Our results suggest that poultry surveillance data can potentially be used as early warning indicators for human H7N9 notifications. Furthermore, we found that human H7N9 incidence at county-level was significantly associated with the presence of wholesale LBMs, the density of retail LBMs, the presence of poultry virological positives, poultry movements from high-risk areas, as well as chicken population density and human population density. The results of this study can influence the current AI H7N9 control program by supporting the integration of poultry surveillance data with human H7N9 notifications as an early warning of the timing and areas at risk for human infection. The findings also highlight areas in China where monitoring of poultry movement and poultry infections could be prioritized.

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“…Closing LBMs appears to be an effective approach for eradicating or reducing H7N9 infections in humans [214]. However, a recent study presented evidence that the closure of LBMs in early waves of H7N9 influenza had resulted in expansion of H7N9 infection to uninfected areas [295]. This implies closing LBMs is a long-term strategy that needs to be further evaluated.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatial risk assessment of the zoonotic influenza A (H7N9) along the live meat chicken market chain in Southeast China

Zhou¹

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Introduction:A new reassortant avian influenza A (H7N9) virus of low pathogenicity to poultry emerged in eastern provinces of China in early 2013. There have been five epidemic waves causing more than 1600 human infections in 29 provinces and municipalities in mainland China till May 2018.Exposure to H7N9 infected live meat chickens at live bird markets (LBMs) within the affected provinces was suggested to be the main risk factor for human infection. Previous studies demonstrated the role of poor biosecurity measures at poultry farms and LBMs and the role of live poultry trade in the dissemination of avian influenza (AI) virus. However, the continued and increasing number of reported human H7N9 cases throughout China indicated that vulnerabilities linked to the live meat chicken market chain remain, that need to be elucidated in order to better design surveillance programmes and health promotion interventions to prevent poultry and human exposure along the live meat chicken market chain. Aims:The overall aim of the research in this thesis is to define the risks of sustained transmission of H7N9 virus along the live meat chicken market chain in eastern China. To meet the aim, studies were sequentially designed with the following specific objectives: 1) identify the effect of market-level risk factors on avian influenza infections in poultry and humans and generate evidence that will inform avian influenza prevention and control programs at LBMs; 2) to understand the role of live poultry movement and live bird market biosecurity in the epidemiology of H7N9 during the emergency; 3) to understand the level of knowledge, attitudes and practices (KAP) on avian influenza of different actors along the live meat chicken market chain and the risk factors associated with their KAP levels; 4) to develop a spatial risk assessment model of the live chicken market chain within the H7N9 high risk area, to provide essential evidence and recommendations for risk-based AI surveillance programs and appropriate enhancements to current prevention and control policies for H7N9 in the study area. Methods:To address each of the specific objectives four studies have been designed. Firstly, we performed a systematic literature review and estimated the pooled odds ratios of biosecurity indicators relating to human and poultry AI infections at market level using a quality effects meta-analysis model. Secondly, we identified the biosecurity risk factors associated with the H7N9 presence in the surveyed LBMs in the affected provinces during the H7N9 emergency response. We also used social network analysis and spatial analysis to quantify the connectivity of counties in Eastern china via live poultry movements and identify highly connected areas associated with human cases. Then, to quantify differences in KAP of AI among different actors (chicken farmers, live chicken vendors and consumers at LBMs) along the live chicken market chain operating within the areas in the Eastern provinces (i.e.ii Shanghai, Jiangsu, and Anhui) identified in the pre...

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Closure of live bird markets leads to the spread of H7N9 influenza in China

Cited by 25 publications

References 19 publications

Pig trade networks through live pig markets in Guangdong Province, China

Pig trade networks through live pig markets in Guangdong Province, China

Geographical variation in the risk of H7N9 human infections in China: implications for risk-based surveillance

Spatial risk assessment of the zoonotic influenza A (H7N9) along the live meat chicken market chain in Southeast China

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