Seroprevalence to Avian Influenza A(H7N9) Virus Among Poultry Workers and the General Population in Southern China: A Longitudinal Study

Wang, Xin; Fang, Shisong; Lü, Xing; Xu, Cuiling; Cowling, Benjamin J.; Tang, Xiujuan; Peng, Bo; Wu, Weihua; He, Jianfan; Tang, Yijun; Xie, Xin; Mei, Shujiang; Kong, Dongfeng; Zhang, Renli; Ma, Hongxia; Cheng, Jinquan

doi:10.1093/cid/ciu399

Cited by 55 publications

(64 citation statements)

References 13 publications

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“…In the general population sample from two provinces examined in this study, we found no indication of infection, consistent with the findings of studies conducted in Zhejiang Province11 and Shenzhen, Guangdong province13 in 2013. Our study also found that among close contacts of infected patients, although several had an elevated HI titer, MN confirmation showed no evidence of infection; this is consistent with the results of a serologic study conducted in Guangdong in July 2013, which included close contacts12.…”

Section: Discussionsupporting

confidence: 92%

“…Another in Guangzhou found 1.6% poultry workers with HI titers ≥40 14 , and a study in Zhejiang Province reported 6.3% poultry workers with HI titers ≥807. Although our study found a lower seropositive rate among poultry workers in Guangdong than prior studies conducted in this province12, 13, 14, our study showed a higher seroprevalence among poultry workers in Guangdong compared with the poultry workers from the other five provinces included in the study. Indeed, both of the two poultry workers with positive H7N9 neutralization antibodies in this study were from Guangdong.…”

Section: Discussioncontrasting

confidence: 87%

“…Although we identified two seropositive cases in poultry workers, the overall seropositivity in this study was much lower than that reported in previous serologic studies conducted in a similar time period11, 13, 14. Compared with studies that did not perform MN testing, the proportion of elevated HI titers in our study (0.1% poultry workers with HI titer ≥20) was also much lower.…”

Section: Discussioncontrasting

confidence: 85%

“…Compared with studies that did not perform MN testing, the proportion of elevated HI titers in our study (0.1% poultry workers with HI titer ≥20) was also much lower. For example, one study among poultry workers in Shenzhen found 7.2%‐14.9% with HI titers ≥16013. Another in Guangzhou found 1.6% poultry workers with HI titers ≥40 14 , and a study in Zhejiang Province reported 6.3% poultry workers with HI titers ≥807.…”

Section: Discussionmentioning

confidence: 99%

“…Serologic studies are needed to identify subclinical influenza A(H7N9) human infections and better describe the full spectrum of influenza A(H7N9) human infection. Although several serologic studies of influenza A(H7N9) have been published, they have been limited to single provinces11, 12, 13, 14 and have used either less sensitive serologic assays11 or lacked confirmation by microneutralization testing11, 13, 14, which improves specificity of serologic testing results15.…”

Section: Introductionmentioning

confidence: 99%

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Sero‐epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013‐2014

Xiang

Bai

Kang

et al. 2017

Influenza Resp Viruses

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BackgroundThe first human infections of novel avian influenza A(H7N9) virus were identified in China in March 2013. Sentinel surveillance systems and contact tracing may not identify mild and asymptomatic human infections of influenza A(H7N9) virus.ObjectivesWe assessed the seroprevalence of antibodies to influenza A(H7N9) virus in three populations during the early stages of the epidemic.Patients/MethodsFrom March 2013 to May 2014, we collected sera from the general population, poultry workers, and contacts of confirmed infections in nine Chinese provinces reporting human A(H7N9) infections and, for contacts, second sera 2‐3 weeks later. We screened for A(H7N9) antibodies by advanced hemagglutination inhibition (HI) assay and tested sera with HI titers ≥20 by modified microneutralization (MN) assay. MN titers ≥20 or fourfold increases in paired sera were considered seropositive.ResultsAmong general population sera (n=1480), none were seropositive. Among poultry worker sera (n=1866), 28 had HI titers ≥20; two (0.11%, 95% CI: 0.02‐0.44) were positive by MN. Among 61 healthcare and 117 non‐healthcare contacts’ sera, five had HI titers ≥20, and all were negative by MN. There was no seroconversion among 131 paired sera.ConclusionsThere was no evidence of widespread transmission of influenza A(H7N9) virus during March 2013 to May 2014, although A(H7N9) may have caused rare, previously unrecognized infections among poultry workers. Although the findings suggest that there were few undetected cases of influenza A(H7N9) early in the epidemic, it is important to continue monitoring transmission as virus and epidemic evolve.

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Section: Discussionsupporting

confidence: 92%

Section: Discussioncontrasting

confidence: 87%

Section: Discussioncontrasting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sero‐epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013‐2014

Xiang

Bai

Kang

et al. 2017

Influenza Resp Viruses

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Swine and Avian Influenza Outbreaks in Recent Times

Fong

2017

Emerging Zoonoses

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Functional growth inhibition of influenza A and B viruses by liquid and powder components of leaves from the subtropical plant Melia azedarach L.

Nerome¹,

Shimizu

Zukeran³

et al. 2018

Arch Virol

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We evaluated the anti-influenza-virus effects of Melia components and discuss the utility of these components. The effects of leaf components of Melia azedarach L. on viruses were examined, and plaque inhibition tests were performed. The in vivo efficacy of M. azedarach L. was tested in a mouse model. Leaf components of Melia azedarach L. markedly inhibited the growth of various influenza viruses. In an initial screening, multiplication and haemagglutination (HA) activities of H1N1, H3N2, H5, and B influenza viruses were inactivated by the liquid extract of leaves of M. azedarach L. (MLE). Furthermore, plaque inhibition titres of H1N1, H3N2, and B influenza viruses treated with MLE ranged from 103.7 to 104.2. MLE possessed high plaque-inhibitory activity against pandemic avian H5N1, H7N9, and H9N2 vaccine candidate strains, with a plaque inhibition titre of more than 104.2. Notably, the buoyant density decreased from 1.175 to 1.137 g/cm3, and spikeless particles appeared. We identified four anti-influenza virus substances: pheophorbide b, pheophorbide a, pyropheophorbide a, and pheophytin a. Photomorphogenesis inside the envelope may lead to removal of HA and neuraminidase spikes from viruses. Thus, MLE could efficiently remove floating influenza virus in the air space without toxicity. Consistent with this finding, intranasal administration of MLE in mice significantly decreased the occurrence of pneumonia. Additionally, leaf powder of Melia (MLP) inactivated influenza viruses and viruses in the intestines of chickens. MLE and MLP may have applications as novel, safe biological disinfectants for use in humans and poultry.

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Seroprevalence to Avian Influenza A(H7N9) Virus Among Poultry Workers and the General Population in Southern China: A Longitudinal Study

Cited by 55 publications

References 13 publications

Sero‐epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013‐2014

Sero‐epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013‐2014

Swine and Avian Influenza Outbreaks in Recent Times

Functional growth inhibition of influenza A and B viruses by liquid and powder components of leaves from the subtropical plant Melia azedarach L.

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