Serologic screenings for H7N9 from three sources among high-risk groups in the early stage of H7N9 circulation in Guangdong Province, China

Wu, Jie; Zou, Lirong; Ni, Hanzhong; Pei, Lei; Zeng, Xianqiao; Liang, Lijun; Zhong, Huan; He, Jianfeng; Song, Yan; Kang, Min; Zhang, Xin; Lin, Junfen; Ke, Changwen

doi:10.1186/1743-422x-11-184

Cited by 6 publications

(6 citation statements)

References 20 publications

(20 reference statements)

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“…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: 90%

“…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%

“…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: 90%

Section: Discussioncontrasting

confidence: 87%

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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“…Along with severe and fatal cases of H7N9 virus infection reported thus far 3 4 9 , mild and asymptomatic infections in humans were also observed by surveillance 3 10 11 12 and serological studies 13 14 15 16 . While few serological studies showed that higher seroprevalence of antibody against H7N9 virus was observed among poultry workers, compared with the general population, the results varied significantly by study 13 14 15 .…”

mentioning

confidence: 66%

Avian influenza A(H7N9) and (H5N1) infections among poultry and swine workers and the general population in Beijing, China, 2013–2015

Yang

Cui

et al. 2016

Sci Rep

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Although several studies have reported seroprevalences of antibody against avian influenza A(H7N9) virus among poultry workers in southern China, results have varied and data in northern China are scarce. To understand risks of H7N9 and H5N1 virus infections in northern China, a serological cohort study was conducted. Poultry workers, swine workers and the general population in Beijing, China, were evaluated through three surveys in November 2013, April 2014 and April 2015. The highest seroprevalence to H7N9 virus among poultry workers was recorded in the April 2014 and April 2015 surveys (0.4%), while that to H5N1 clade 2.3.4 or clade 2.3.2.1 virus was noted in the April 2014 survey (1.6% and 0.2%, respectively). The incidence of H7N9 virus infections among poultry workers (1.6/1000 person-months) was significantly lower than that of H5N1 clade 2.3.4 infections (3.8/1000 person-months) but higher than that of H5N1 clade 2.3.2.1 infections (0.3/1000 person-months). Compared with the general population, poultry workers were at higher risk of contracting H7N9 virus (IRR: 34.90; p < 0.001) or H5N1 clade 2.3.4 virus (IRR: 10.58; p < 0.001). Although risks of H7N9 and H5N1 virus infections remain low in Beijing, continued preventive measures are warranted for poultry workers.

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“…After the virus shedding period, serologic assays are performed to detect virus specific antibodies [10,11].…”

Section: Introductionmentioning

confidence: 99%

Establish and Apply a Safe and Convenient Pseudovirus-Based Assay to Detect Neutralizing Antibodies against Influenza A (H7N9) Virus

Zhang

et al. 2017

Preprint

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Abstract:In March 2013, a novel avian influenza A H7N9 virus was emerged in China, which cause rapidly progressive pneumonia and with a high fatality rate. Serologic studies to evaluate neutralizing antibodies of infected patients and birds are invaluable tools for immunogenicity research of H7N9 and epidemiological investigation. Conventional neutralization assays are laborious and time-consuming which also hampered by biosafety requirement. In this study, We construct and produce pseudovirus bearing the full-length hemagglutinin (HA) of H7N9 virus in the Env-defective, luciferase-expressing HIV-1 backbone. The production of lentiviral pseudovirus was analysed by HA gene specific real-time reverse-transcription PCR, transmission electron microscopy (TEM), and Western Blot assay to prove the nucleic acid replication, the morphology of virus, and the expression of HA protein in pseudovirus. After that pseudovirus based inhibition assay was established to detect neutralizing antibodies of a panel of serum samples. Our results demonstrated that H7N9 pseudovirus which had single-cycle infection was generated. By comparing the neutralization antibody titers, pseudovirus based neutralization test could be recognized as an alternative of conventional microneutralization (MN). Hence, we conclude that it is possible to use pseudovirus inhibition assay to screen sera samples, as well as evaluate vaccine-induced neutralizing antibodies against H7N9 virus.

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Serologic screenings for H7N9 from three sources among high-risk groups in the early stage of H7N9 circulation in Guangdong Province, China

Cited by 6 publications

References 20 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

Avian influenza A(H7N9) and (H5N1) infections among poultry and swine workers and the general population in Beijing, China, 2013–2015

Establish and Apply a Safe and Convenient Pseudovirus-Based Assay to Detect Neutralizing Antibodies against Influenza A (H7N9) Virus

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