Antibodies elicited by Newcastle disease virus-vectored H7N9 avian influenza vaccine are functional in activating the complement system

H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.

Distribution of Avian Influenza A Viruses in Poultry-Related Environment and Its Association with Human Infection in Henan, 2016 to 2017

Objective To survey avian influenza A viruses(AIVs) in the environment and explore the reasons for the surge in human H7 N9 cases.Methods A total of 1,045 samples were collected from routine surveillance on poultry-related environments and 307 samples from human H7 N9 cases-exposed environments in Henan from 2016 to2017. The nucleic acids of influenza A(Flu A), H5, H7, and H9 subtypes were detected by real-time polymerase chain reaction.Results A total of 27 H7 N9 cases were confirmed in Henan from 2016 to 2017, 24 had a history of live poultry exposure, and 15 had H7 N9 virus detected in the related live poultry markets(LPMs). About 96%(264/275) Flu A positive-environmental samples were from LPMs. H9 was the main AIV subtype(10.05%) from routine surveillance sites with only 1 H7-positive sample, whereas 21.17% samples were H7-positive in H7 N9 cases-exposed environments. Samples from H7 N9 cases-exposed LPMs(47.56%)had much higher AIVs positive rates than those from routine surveillance sites(12.34%). The H7+H9 combination of mixed infection was 78.18%(43/55) of H7-positive samples and 41.34%(43/104) of H9-positive samples.Conclusion The contamination status of AIVs in poultry-related environments is closely associated with the incidence of human infection caused by AIVs. Therefore, systematic surveillance of AIVs in LPMs in China is essential for the detection of novel reassortant viruses and their potential for interspecies transmission.

Environmental connections of novel avian-origin H7N9 influenza virus infection and virus adaptation to the human

A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.

Human infection with avian influenza A（H7N9） virus in Shanghai： current status and future trends

Avian influenza A（H7N9） virus is one subgroup among the larger group of H7 viruses,which normally circulate among birds.The H7N9 subtype of avian influenza viruses has not been known to infect humans until only recently.On March 31,2013,China confirmed the first three human cases of novel avian influenza A（H7N9）infection in Shanghai and Anhui,two of these patients died.1 As of February 27,2014,367 laboratory-confirmed human cases have been reported from 15 provinces/municipalities in China's Mainland,

First outbreak of human infection with avian influenza A(H7N9) virus in Guangxi, China, 2016 to 2017

To the Editor: Since avian influenza A(H7N9) was first identified in Shanghai, China, in March 2013, there have been a total of five epidemics. These have amounted to 1564 laboratory-confirmed cases up to September 2017, with a fatality rate of about 40%.[1] In the fifth wave, 4.09% of cases (31/758) were infected with the highly pathogenic avian influenza (HPAI) A(H7N9). This indicated that the pathotype of the A(H7N9) had switched from low pathogenic avian influenza (LPAI) to HPAI.

New light shed on global epidemiology of avian influenza A H5N1 virus infection in humans,1997—2015

With the support by the National Natural Science Foundation of China,the research team led by Prof.Yu Hongjie(余宏杰)at the School of Public Health,Fudan University,Key Laboratory of Public Health Safety,Ministry of Education,and the Key Laboratory of Surveillance and Early Warning on Infectious Disease,Chinese Center for Disease Control and Prevention,has published the paper entitled“Global epi-

Discovery process, clinical characteristics, and treatment of patients infected with avian influenza virus （H7N9） in Shanghai

During the spring of 2013,a novel avian-origin influenza A （H7N9） virus emerged and spread in Shanghai.On May 9,2013,33 lab-confirmed cases （2 children and 31 adults） have been reported,among whom 13 died.Among the 31 adult cases of H7N9 avian influenza A virus infections in humans,80.6% （25/31） were older men （average age 65 years）.Clear history of poultry exposure was found in eight patients （8/33,24.3%） and the remaining 21 cases had been suspected poultry exposure.Clustered cases were found in two families （two cases from a father and his son,and the other two cases from a wife and her husband）.However,no evidence of human-to-human transmission had been identified.Avian influenza is one of the most dangerous contagions in poultry worldwide,and avian influenza A virus is the major pathogen responsible.Transmission from poultry to humans has now been proven.Some gene segments of the strain have mutated,and further mutations might result in human-to-human transmission.

2014 update of the Chinese guidelines for diagnosis and treatment of avian influenza A（H7N9） virus infection

The National Health and Family Planning Commission of China published an updated guidance （2014 version） on clinical management in Chinese on January 26, 2014.The guidelines come as human cases of avian influenza A（H7N9） virus infection undergo a seasonal spike.

Veno-venous extracorporeal membrane oxygenation for patient with a history of open cholecystectomy and acute respiratory distress syndrome caused by coinfection of avian influenza A (H7N9) and Epstein-Barr virus

To the Editor:Most patients infected with avian influenza A (H7N9) rapidly develop progressive pneumonia and acute respiratory distress syndrome (ARDS), a heterogeneous disorder that is refractory to conventional mechanical ventilation. Most H7N9 patients also have underlying disease such as chronic obstructive pulmonary disease, hypertension, diabetes mellitus, and heart diseases, and are more susceptible to coinfections. For these patients with such serious complications, extracorporeal membrane oxygenation (ECMO) support can be adopted as a feasible life-saving therapy Here, we present our successful experience with ECMO utilized in a patient with ARDS and also with H 7N9 and Epstein-Barr virus (EBV) infection.

Vaccination of poultry successfully eliminated human infection with H7N9 virus in China

The H7 N9 viruses that emerged in China in 2013 were nonpathogenic in chickens but mutated to a highly pathogenic form in early 2017 and caused severe disease outbreaks in chickens. The H7 N9 influenza viruses have caused five waves of human infection, with almost half of the total number of human cases(766 of 1,567) being reported in the fifth wave, raising concerns that even more human infections could occur in the sixth wave. In September 2017, an H5/H7 bivalent inactivated vaccine for chickens was introduced, and the H7 N9 virus isolation rate in poultry dropped by 93.3% after vaccination. More importantly,only three H7 N9 human cases were reported between October 1, 2017 and September 30, 2018, indicating that vaccination of poultry successfully eliminated human infection with H7 N9 virus. These facts emphasize that active control of animal disease is extremely important for zoonosis control and human health protection.

Human avian influenza A (H5N1) virus infection in China

Highly pathogenic influenza A (H5N1) virus causes a widespread poultry deaths worldwide. The first human H5N1 infected case was reported in Hong Kong Special Administrative Region of China in 1997. Since then, the virus re-emerged in 2003 and continues to infect people worldwide. Currently, over 400 human infections have been reported in more than 15 countries and mortality rate is greater than 60%. H5N1 viruses still pose a potential pandemic threat in the future because of the continuing global spread and evolution. Here, we summarize the epidemiological, clinical and virological characteristics of human H5N1 infection in China monitored and identified by our national surveillance systems.

Clinical characteristics of human infection with a novel avian-origin influenza A（H10N8） virus

Background Novel influenza A viruses of avian-origin may be the precursors of pandemic strains. This descriptive study aims to introduce a novel avian-origin influenza A （H10N8） virus which can infect humans and cause severe diseases. Methods Collecting clinical data of three cases of human infection with a novel reassortment avian influenza A （H10N8） virus in Nanchang, Jiangxi Province, China. Results Three cases of human infection with a new reassortment avian influenza A（H10N8） virus were described, of which two were fatal cases, and one was severe case. These cases presented with severe pneumonia that progressed to acute respiratory distress syndrome （ARDS） and intractable respiratory failure. Conclusion This novel reassortment avian influenza A （H10N8） virus in China resulted in fatal human infections, and should be added to concerns in clinical practice.

Novel human H7N9 influenza virus in China

Outbreaks of H7N9 avian influenza in humans in 5 provinces and 2 municipalities of China have reawakened concern that avian influenza viruses may again cross species barriers to infect the human population and thereby initiate a new influenza pandemic.Evolutionary analysis shows that human H7N9 influenza viruses originated from the H9N2,H7N3 and H11N9 avian viruses,and that it is as a novel reassortment influenza virus.This ar­ticle reviews current knowledge on 11 subtypes of influenza A virus from human which can cause human infec­tions.

Fungal spondylodiscitis in a patient recovered from H7N9 virus infection:a case study and a literature review of the differences between Candida and Aspergillus spondylodiscitis

To report a rare case of fungal spondylodiscitis in a patient recovered from H7N9 virus infection and perform a literature review of the different characteristics of Candida and Aspergillus spondylodiscitis, we reviewed cases of spondylodiscitis caused by Candida and Aspergillus species. Data, including patients＇ information, patho- genic species, treatment strategy, outcomes, and relapses, were collected and summarized. The characteristics of Canclida and Aspergillus spondylodiscitis were compared to see if any differences in clinical features, management, or consequences could be detected. The subject of the case study was first misdiagnosed as having a vertebral tumor, and then, following open biopsy, was diagnosed as having fungal spondylodiscitis. The patient made a good recovery following radical debridement. Seventy-seven additional cases of Candida spondylodiscitis and 94 cases of Asper- gillus spondylodiscitis were identified in the literature. Patients with Candida spondylodiscitis tended to have a better outcome than patients with Aspergillus spondylodiscitis （cure rate 92.3% vs. 70.2%）. Candida was found more fre- quently （47.8%） than Aspergillus （26.7%） in blood cultures, while neurological deficits were observed more often in patients with Aspergillus spondylodiscitis （43.6% vs. 25.6%）. Candida spinal infections were more often treated by radical debridement （60.5% vs. 39.6%）. Patients with Candida spondylodiscitis have better outcomes, which may be associated with prompt recognition, radical surgical debridement, and azoles therapy. A good outcome can be ex- pected in fungal spondylodiscitis with appropriate operations and anti-fungal drugs.

Economic burden and its associated factors of hospitalized patients infected with A (H7N9) virus: a retrospective study in Eastern China, 2013–2014

Background:H7N9 continues to cause human infections and remains a pandemic concern.Understanding the economic impacts of this novel disease is important for making decisions on health resource allocation,including infectious disease prevention and control investment.However,there are limited data on such impacts.Methods:Hospitalized laboratory-confirmed H7N9 patients or their families in Jiangsu Province of China were interviewed.Patients’direct medical costs of hospitalization were derived from their hospital bills.A generalized linear model was employed to estimate the mean direct medical costs of patients with different characteristics.Results:The mean direct cost of hospitalization for H7N9 was estimated to be¥71060(95%CI,48180–104820),i.e.,US$10996(95%CI,7455–16220),and was¥12060(US$1861),¥136120(US$21001)and¥218610(US$33728)for those who had mild or severe symptoms or who died,respectively.The principal components of the total fees differed among patients with different disease severity,although medication fees were always the largest contributors.Disease severity,proportion of reimbursement and family member monthly average income were identified as the key factors that contributed to a patient’s direct medical cost of hospitalization.Conclusions:The direct medical costs of hospitalized patients with H7N9 are significant,and far surpass the annual per capita income of Jiangsu Province,China.The influencing factors identified should be taken into account when developing related health insurance policies and making health resource allocation.Trial registration:Not applicable.This is a survey study with no health care intervention implemented on human participants.

Conserved peptides enhance immune efficiency of inactive vaccines against emerging avian influenza viruses in chicken

Avian influenza viruses(AIVs) such as H5N1 and H7N9 are a great threat to poultry economics and public health. Vaccination can effectively inhibit the spread of AIV in poultry, which is also a viable strategy for controlling virus transmission from poultry to human. Adjuvants that are commonly used in current inactivated vaccines to provide stronger anti-AIV immune responses are often limited in their capacity to quantitatively induce both humoral and cellular immune responses. Herein, we assessed the levels of immune responses generated by a vaccine formulation comprising inactivated H5N1 antigen and synthetic peptides covering conserved CD4^+, CD8^+ T cell, and B cell epitopes. We found that the synthetic peptides enhanced the antibody responses against conserved influenza virus antigen M2 e. Notably, the hemagglutination inhibition test results indicated that the peptides significantly augmented the antibody responses of inactivated H5N1 antigen even in the 1/10 or 1/5 dose group, in the identical antibody level as antigen alone used at the full dose. This indicates that the peptide can significantly reduce the use of inactivated virus, lowering the cost of the vaccine. Moreover, the peptides increased the transcript levels of interleukin-4 and interferon-γcytokines in chicken peripheral blood mononuclear cells, which may facilitate both humoral and cellular immune responses. Our data suggest that this peptide combined with inactivated H5N1 antigen enhances both the humoral and cellular immune responses,which may benefit the prediction and design of synthetic peptide-based adjuvants for vaccines in chicken.

Human T-cell immunity against the emerging and re-emerging viruses

Over the past decade, we have seen an alarming number of high-profile outbreaks of newly emerging and re-emerging viruses.Recent outbreaks of avian influenza viruses, Middle East respiratory syndrome coronaviruses, Zika virus and Ebola virus present great threats to global health. Considering the pivotal role of host T-cell immunity in the alleviation of symptoms and the clearance of viruses in patients, there are three issues to be primarily concerned about T-cell immunity when a new virus emerges: first, does the population possess pre-existing T-cells against the new virus through previous infections of genetically relevant viruses; second, does a proper immune response arise in the patients to provide protection through an immunopathogenic effect; lastly, how long can the virus-specific immune memory persist. Herein, we summarize the current updates on the characteristics of human T-cell immunological responses against recently emerged or re-emerged viruses, and emphasize the necessity for timely investigation on the T-cell features of these viral diseases, which may provide beneficial recommendations for clinical diagnosis and vaccine development.

人感染H7N9禽流感引发的传染病学教学思考

人感染H7N9禽流感疫情引发教学者对传染病学教学的思考，分析当前传染病学教学面临的挑战：传染病疾病谱发生巨大变化，但教学课时有限；传染病发病率下降，而适宜的教学病例有限；医学生对传染病学学习存在畏惧心理；教学师资缺乏；公众对传染病防控要求越来越高等。由此提出以下应对策略：调整课程设置；注重教学病例积累，使用多媒体教学，利用专科医院的教学资源；教育学生学会自身防护；注重青年教师培养；强调学科特征及公共卫生的重要性；改进教学方法，提高教学效率。

Experience and practice of the Emergency Operations Centerz Chinese Center for Disease Control and Prevention:a case study of response to the H7N9 outbreak

Background:Emergency Operations Center(EOC)is a place to provide response to public health emergencies.Chinese Center for Disease Control and Prevention(China CDC)'s EOC was officially established in 2016,which has been the core department for the public health emergencies and risk response.In recent years,we have been continuously improving the function of EOC through many incidents.In the study,we hope to share the construction status,operation management experience of China CDC's EOC and the response process in the human avian influenza A(H7N9)outbreak.Main text:The China CDC's EOC mainly focus on building the five core elements including sites/places and facilities,information and data,plans and procedures,training and exercises,and logistics.Based on summarizing previous emergency respons巳the China CDC's EOC established its own incident management and the standardized response procedures.The event-specific data,context-specific data and event management data could be obtained through various source.The logistics department of the EOC also provides comprehensive support.The well-trained staff is another necessary conditions for its operation.Through sharing the response process of H7N9 outbreak,it further explains the EOC's functions in the five phases of outbreak response,such as the formulation of the incident response framework,monitoring,personnel dispatch and resource mobilization.Conclusions:The EOC con tributes to faster and more efficient responses during emergencies which en able a greater reduction in morbidity and mortality.Compared with the traditional incident response process,under the command and coordination of China CDC's EOC,each group involved in the response has a clearer goal,responsibilities and tasks at each stage.Meanwhile,each group also gave full play to its own expertise and advantages.As a whole,incident response tended to be more specialized and precise,which generally improves the efficiency of incident response.However,different countries and regions have different response processes to the events.We still suggested that appropriate emerge ncy operati on plan should be made according to the complexity of in cident response in the region when constructing response mechanism,through our experience.And the China CDC's EOC is still at growing and groping phase.