Poultry Market Closures and Human Infection with Influenza A(H7N9) Virus, China, 2013–14

Wu, Peng; Jiang, Hui; Wu, Joseph T.; Chen, Enfu; He, Jianfeng; Zhou, Hang; Wei, Lan; Yang, Juan; Yang, Bingyi; Qin, Ying; Fang, Vicky J.; Li, Ming; Tsang, Tim K.; Zheng, Jiandong; Lau, Eric H. Y.; Cao, Yu; Chai, Chengliang; Zhong, Huan; Li, Zhongjie; Leung, Gabriel M.; Feng, Luzhao; Gao, George F.; Cowling, Benjamin J.; Yu, Hongjie

doi:10.3201/eid2011.140556

Cited by 51 publications

(49 citation statements)

References 11 publications

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“…Population contact with live poultry decreased in influenza A(H7N9) virus–affected and –nonaffected areas after cases were detected in China, although exposure to live poultry in urban and rural areas remained high in the country ( 12 ). Live poultry markets in China, particularly in cities, have been closing either temporarily or permanently since the first wave in 2013 ( 2 , 13 ). Some cities severely affected by influenza A(H7N9) virus in the Yangtze River Delta permanently closed all live poultry markets in 2014, which led to a substantial decline in population exposure to the virus and the risk for infection.…”

Section: Discussionmentioning

confidence: 99%

Human Infection with Influenza A(H7N9) Virus during 3 Major Epidemic Waves, China, 2013–2015

Wu¹,

Peng²,

Fang³

et al. 2016

Emerg. Infect. Dis.

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Section: Discussionmentioning

confidence: 99%

Human Infection with Influenza A(H7N9) Virus during 3 Major Epidemic Waves, China, 2013–2015

Wu¹,

Peng²,

Fang³

et al. 2016

Emerg. Infect. Dis.

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“…While influenza virus may be transmitted among humans via fomites, droplets, or aerosols (28), the mode of H7N9 transmission remains unclear. Closure of live-poultry markets was effective in temporarily reducing human cases (29)(30)(31), but close to 200 human infections were reported during the winter of 2014-2015, with a wider geographic distribution to Xinjiang and Jilin in 2014 (1). While chicken is the most common species in the live-poultry markets harboring the H7N9 virus (6,32,33), the predominant mode that facilitates the spread of H7N9 virus among poultry is also not fully understood.…”

mentioning

confidence: 99%

Transmission of H7N9 Influenza Viruses with a Polymorphism at PB2 Residue 627 in Chickens and Ferrets

Luk

Leung

Sia

et al. 2015

J Virol

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Poultry exposure is a major risk factor for human H7N9 zoonotic infections, for which the mode of transmission remains unclear. We studied the transmission of genetically related poultry and human H7N9 influenza viruses differing by four amino acids, including the host determinant PB2 residue 627. A/Silkie chicken/HK/1772/2014 (SCk1772) and A/HK/3263/14 (HK3263) replicated to comparable titers in chickens, with superior oropharyngeal over cloacal shedding; both viruses transmitted efficiently among chickens via direct contact but inefficiently via the airborne route. Interspecies transmission via the airborne route was observed for ferrets exposed to the SCk1772-or HK3263-infected chickens, while low numbers of copies of influenza viral genome were detected in the air, predominantly at particle sizes larger than 4 m. In ferrets, the human isolate HK3263 replicated to higher titers and transmitted more efficiently via direct contact than SCk1772. We monitored "intrahost" and "interhost" adaptive changes at PB2 residue 627 during infection and transmission of the Sck1772 that carried E627 and HK3263 that carried V/K/E polymorphism at 60%, 20%, and 20%, respectively. For SCk1772, positive selection for K627 over E627 was observed in ferrets during the chicken-to-ferret or ferret-to-ferret transmission. For HK3263 that contained V/K/E polymorphism, mixed V627 and E627 genotypes were transmitted among chickens while either V627 or K627 was transmitted to ferrets with a narrow transmission bottleneck. Overall, our results suggest direct contact as the main mode for H7N9 transmission and identify the PB2-V627 genotype with uncompromised fitness and transmissibility in both avian and mammalian species. IMPORTANCEWe studied the modes of H7N9 transmission, as this information is crucial for developing effective control measures for prevention. Using chicken (SCk1772) and human (HK3263) H7N9 isolates that differed by four amino acids, including the host determinant PB2 residue 627, we observed that both viruses transmitted efficiently among chickens via direct contact but inefficiently via the airborne route. Chicken-to-ferret transmission via the airborne route was observed, along with the detection of viral genome in the air at low copy numbers. In ferrets, HK3263 transmitted more efficiently than SCk1772 via direct contact. During the transmission of SCk1772 that contained E and HK3263 that contained V/K/E polymorphism at PB2 residue 627, positive selections of E627 and K627 were observed in chickens and ferrets, respectively. In addition, PB2-V627 was transmitted and stably maintained in both avian and mammalian species. Our results support applying intervention strategies that minimize direct and indirect contact at the poultry markets during epidemics.

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“…Closure of LPMs was conducted to block the transmission of H7N9 and has been considered as the most effective method for restricting the epidemic to date in China 3, 11, 17. Zhejiang Province closed all LPMs in central urban areas concerning the high incidence of H7N9 cases in July 2014, prior to the third wave.…”

Section: Discussionmentioning

confidence: 99%

“…Epidemiological data suggested that avian influenza A(H7N9) infections were associated with exposure to live poultry markets (LPMs) 2, 3, 4, 5, 6. To control its impact, temporary or permanent closure of live poultry markets has been implemented by many local governments, leading to a declining trend of laboratory‐confirmed cases in the first four waves 7, 8, 9, 10, 11. However, an unprecedented outbreak of human infection with avian influenza A(H7N9) virus, identified as the fifth wave, occurred in China from September 2016, and a number of cases reported in the fifth wave exceeded those reported in the previous waves in China 8, 9, 10, 12…”

Section: Introductionmentioning

confidence: 99%

Comparison of the three waves of avian influenza A(H7N9) virus circulation since live poultry markets were permanently closed in the main urban areas in Zhejiang Province, July 2014‐June 2017

Cheng

Wang

Shen

et al. 2018

Influenza Resp Viruses

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BackgroundThe sudden increase in the number of human cases infected with avian influenza A(H7N9) virus after September 2016 raised global concern.ObjectivesTo assess the changes in epidemiological characteristics of H7N9 cases since the massive closure of live poultry markets (LPMs) in the main urban areas in Zhejiang province.MethodsWe used descriptive statistics to compare epidemiological characteristics of the three distinct waves of H7N9 cases in Zhejiang province. The rural or urban cases were defined according to the location where the patients had exposure within 2 weeks before illness onset.ResultsBetween July 2014 and June 2017, 166 H7N9 cases were reported in Zhejiang province, with 45, 34, and 87 cases reported in the third, fourth, and fifth wave, respectively. Across the three waves, most reported cases were from rural areas. A similar percentage of cases in all three waves reported exposure to LPMs, raising poultry at home or around the house, as well as occupational exposure. Compared to the third (80.00%) and fourth wave (70.59%), a significantly larger proportion of cases from the non‐LPMs closure areas were observed in the fifth wave (89.66%) (P = .034).ConclusionEpidemiological characteristics of human cases infected with avian influenza A(H7N9) virus had generally remained unchanged since the massive closure of LPMs in the main urban area of Zhejiang province. The sudden increase in the number of H7N9 cases in the fifth wave was mainly attributed to the excessive cases reported from areas where LPMs were not permanently closed.

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Poultry Market Closures and Human Infection with Influenza A(H7N9) Virus, China, 2013–14

Cited by 51 publications

References 11 publications

Human Infection with Influenza A(H7N9) Virus during 3 Major Epidemic Waves, China, 2013–2015

Human Infection with Influenza A(H7N9) Virus during 3 Major Epidemic Waves, China, 2013–2015

Transmission of H7N9 Influenza Viruses with a Polymorphism at PB2 Residue 627 in Chickens and Ferrets

Comparison of the three waves of avian influenza A(H7N9) virus circulation since live poultry markets were permanently closed in the main urban areas in Zhejiang Province, July 2014‐June 2017

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