Effect of Live Poultry Market Interventions on Influenza A(H7N9) Virus, Guangdong, China

Wu, Jie; Lu, Jing; Faria, Nuno Rodrigues; Zeng, Xianqiao; Song, Yan; Zou, Lirong; Liu, Yi; Liang, Lijun; Ni, Hanzhong; Kang, Min; Zhang, Xin; Huang, Guofeng; Zhong, Huan; Bowden, Thomas A.; Raghwani, Jayna; He, Jianfeng; He, Xiang; Lin, Junfen; Pybus, Oliver G.; Ke, Changwen

doi:10.3201/eid2212.160450

Cited by 33 publications

(28 citation statements)

References 25 publications

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“…Chilled chickens are slaughtered and packaged chicken stored at between 0°C and 4°C after going through a chilling process and has a shelf-life of 5-7 days, which can highly reduce the risk of virus transmission from live poultry to human [23]. Since the outbreaks of H7N9, many cities that reported the cases have launched a pilot program (named "Centralized Slaughtering, Cold Chain Delivery, Chilled Poultry Supply") in designated areas, such as 2013 in Shanghai, 2014 in Guangzhou and Shenzhen [11].…”

Section: Lpms Reopen and Temporary Interventions Cannot Completely Hamentioning

confidence: 99%

“…To prevent the poultry-to-human transmission of this novel virus, many cities in the pearl and Yangtze river deltas implemented the LPMs closure. Once the confirmed H7N9 cases were reported in a city, the government implemented the LPMs closure and slaughtered or transferred the live poultries to decrease the disease-causing contact chance, and the numbers of new-onset human H7N9 viral infections decreased rapidly [10,11] [12]. For instance, one strict prevention and control measures were used to conduct in Guangdong Province, which was daily cleaning of the market, weekly disinfection of the market and monthly closings of the live market.…”

Section: Introductionmentioning

confidence: 99%

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

Chen¹,

Cheng

et al. 2020

Preprint

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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.

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Section: Lpms Reopen and Temporary Interventions Cannot Completely Hamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Chen¹,

Cheng

et al. 2020

Preprint

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“…The physical location of the LBM is only one among many possible transaction sites. Our results showed that temporary market closure for 7 days is likely to lead to establishment of parallel, informal, and uncontrolled live poultry trade, which could lead to virus introduction into non-affected areas ( 29 ). Our study concludes that given the structure of Vietnam’s poultry value chain, which remains highly flexible with numerous middlemen between producer and consumer, closure of LBMs, unless implemented on a longer term and in a larger geographical area or nationwide, will be an ineffective strategy for reducing the risk of AI.…”

Section: Discussion: Value Chain Flexibility and The Ecology Of Aimentioning

confidence: 87%

A Stakeholder Survey on Live Bird Market Closures Policy for Controlling Highly Pathogenic Avian Influenza in Vietnam

et al. 2017

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Extensive research in Vietnam and elsewhere has shown that live bird markets (LBMs) play a significant role in the ecology and zoonotic transmission of avian influenzas (AIs) including H5N1 and H7N9. Vietnam has a large number of LBMs reflecting the consumer preferences for live poultry. Under pressure to mitigate risks for H7N9 and other zoonotic AIs, Vietnam is considering, among other mitigation measures, temporary closures of LBMs as a policy to reduce risk of AI outbreaks. However, the efficacy of market closure is debated, particularly because little is known about how poultry traders may react, and whether trading may emerge outside formal marketplaces. Combining efforts of anthropologists, economists, sociologists, and veterinarians can be useful to elucidate the drivers behind poultry traders’ reactions and better understanding the barriers to implementing risk mitigation measures. In this paper, we present results from a stakeholder survey of LBM stakeholders in Vietnam. Our qualitative data show that trading outside formal markets is very likely to occur in the event of a temporary LBM market closure. Our data show that the poultry value chain in Vietnam remains highly flexible, with traders willing and able to trade poultry in many possible locations. Our results indicate that simplification of the poultry value chain along with strict enforcement, engagement of stakeholders, and adequate communication would be a necessary prerequisite before market closure could be an effective policy.

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Section: Discussionmentioning

confidence: 99%

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

Chen¹,

Cheng

et al. 2020

Preprint

View full text Add to dashboard Cite

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.

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Effect of Live Poultry Market Interventions on Influenza A(H7N9) Virus, Guangdong, China

Abstract: Temporary closure of these markets appears not to have halted virus transmission or prevented its dissemination.

Cited by 33 publications

References 25 publications

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

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

A Stakeholder Survey on Live Bird Market Closures Policy for Controlling Highly Pathogenic Avian Influenza in Vietnam

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

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