Quantification of complete viral particles in inactivated avian influenza virus antigen by high performance size exclusion chromatography coupled with multi-angle laser light scattering / 生物工程学报

We developed a method for accurate quantification of the intact virus particles in inactivated avian influenza virus feedstocks. To address the problem of impurities interference in the detection of inactivated avian influenza virus feedstocks by direct high performance size exclusion chromatography (HPSEC), we firstly investigated polyethylene glycol (PEG) precipitation and ion exchange chromatography (IEC) for H5N8 antigen purification. Under the optimized conditions, the removal rate of impurity was 86.87% in IEC using DEAE FF, and the viral hemagglutination recovery was 100%. HPSEC was used to analyze the pretreated samples. The peak of 8.5-10.0 min, which was the characteristic adsorption of intact virus, was analyzed by SDS-PAGE and dynamic light scattering. It was almost free of impurities and the particle size was uniform with an average particle size of 127.7 nm. After adding antibody to the IEC pretreated samples for HPSEC detection, the characteristic peak disappeared, indicating that IEC pretreatment effectively removed the impurities. By coupling HPSEC with multi-angle laser scattering technique (MALLS), the amount of intact virus particles in the sample could be accurately quantified with a good linear relationship between the number of virus particles and the chromatographic peak area (R2=0.997). The established IEC pretreatment-HPSEC-MALLS assay was applied to accurate detection of the number of intact virus particles in viral feedstocks of different subtypes (H7N9), different batches and different concentrations, all with good applicability and reproducibility, Relative standard deviation < 5%, n=3.

Characterization of a monoclonal antibody against the hemagglutinin stem of H7N9 subtype avian influenza virus / 生物工程学报

The conserved hemagglutinin (HA) stem region of avian influenza virus (AIV) is an important target for designing broad-spectrum vaccines, therapeutic antibodies and diagnostic reagents. Previously, we obtained a monoclonal antibody (mAb) (5D3-1B5) which was reactive with the HA stem epitope (aa 428-452) of H7N9 subtype AIV. To systematically characterize the mAb, we determined the antibody titers, including the HA-binding IgG, hemagglutination-inhibition (HI) and virus neutralizing (VN) titers. In addition, the antigenic epitope recognized by the antibody as well as the sequence and structure of the antibody variable region (VR) were also determined. Moreover, we evaluated the cross-reactivity of the antibody with influenza virus strains of different subtypes. The results showed that the 5D3-1B5 antibody had undetectable HI and VN activities against H7N9 virus, whereas it exhibited strong reactivity with the HA protein. Using the peptide-based enzyme-linked immunosorbent assay and biopanning with a phage-displayed random peptide library, a motif with the core sequence (431W-433Y-437L) in the C-helix domain in the HA stem was identified as the epitope recognized by 5D3-1B5. Moreover, the mAb failed to react with the mutant H7N9 virus which contains mutations in the epitope. The VR of the antibody was sequenced and the complementarity determining regions in the VR of the light and heavy chains were determined. Structural modeling and molecular docking analysis of the VR verified specific binding between the antibody and the C-helix domain of the HA stem. Notably, 5D3-1B5 showed a broad cross-reactivity with influenza virus strains of different subtypes belonging to groups 1 and 2. In conclusion, 5D3-1B5 antibody is a promising candidate in terms of the development of broad-spectrum virus diagnostic reagents and therapeutic antibodies. Our findings also provided new information for understanding the epitope characteristics of the HA protein of H7N9 subtype AIV.

A broadly neutralizing human monoclonal antibody against the hemagglutinin of avian influenza virus H7N9 / 中华医学杂志(英文版)

BACKGROUND@#The new emerging avian influenza A H7N9 virus, causing severe human infection with a mortality rate of around 41%. This study aims to provide a novel treatment option for the prevention and control of H7N9.@*METHODS@#H7 hemagglutinin (HA)-specific B cells were isolated from peripheral blood plasma cells of the patients previously infected by H7N9 in Jiangsu Province, China. The human monoclonal antibodies (mAbs) were generated by amplification and cloning of these HA-specific B cells. First, all human mAbs were screened for binding activity by enzyme-linked immunosorbent assay. Then, those mAbs, exhibiting potent affinity to recognize H7 HAs were further evaluated by hemagglutination-inhibiting (HAI) and microneutralization in vitro assays. Finally, the lead mAb candidate was selected and tested against the lethal challenge of the H7N9 virus using murine models.@*RESULTS@#The mAb 6-137 was able to recognize a panel of H7 HAs with high affinity but not HA of other subtypes, including H1N1 and H3N2. The mAb 6-137 can efficiently inhibit the HA activity in the inactivated H7N9 virus and neutralize 100 tissue culture infectious dose 50 (TCID50) of H7N9 virus (influenza A/Nanjing/1/2013) in vitro, with neutralizing activity as low as 78 ng/mL. In addition, the mAb 6-137 protected the mice against the lethal challenge of H7N9 prophylactically and therapeutically.@*CONCLUSION@#The mAb 6-137 could be an effective antibody as a prophylactic or therapeutic biological treatment for the H7N9 exposure or infection.

Avian influenza A (H7N9) virus: from low pathogenic to highly pathogenic / 医学前沿

The avian influenza A (H7N9) virus is a zoonotic virus that is closely associated with live poultry markets. It has caused infections in humans in China since 2013. Five waves of the H7N9 influenza epidemic occurred in China between March 2013 and September 2017. H7N9 with low-pathogenicity dominated in the first four waves, whereas highly pathogenic H7N9 influenza emerged in poultry and spread to humans during the fifth wave, causing wide concern. Specialists and officials from China and other countries responded quickly, controlled the epidemic well thus far, and characterized the virus by using new technologies and surveillance tools that were made possible by their preparedness efforts. Here, we review the characteristics of the H7N9 viruses that were identified while controlling the spread of the disease. It was summarized and discussed from the perspectives of molecular epidemiology, clinical features, virulence and pathogenesis, receptor binding, T-cell responses, monoclonal antibody development, vaccine development, and disease burden. These data provide tools for minimizing the future threat of H7N9 and other emerging and re-emerging viruses, such as SARS-CoV-2.

Clinical indices and mortality of hospitalized avian influenza A (H7N9) patients in Guangdong, China / 中华医学杂志(英文版)

BACKGROUND@#Six epidemic waves of human infection with avian influenza A (H7N9) virus have emerged in China with high mortality. However, study on quantitative relationship between clinical indices in ill persons and H7N9 outcome (fatal and non-fatal) is still unclear. A retrospective cohort study was conducted to collect laboratory-confirmed cases with H7N9 viral infection from 2013 to 2015 in 23 hospitals across 13 cities in Guangdong Province, China.@*METHODS@#Multivariable logistic regression model and classification tree model analyses were used to detect the threshold of selected clinical indices and risk factors for H7N9 death. The receiver operating characteristic curve (ROC) and analyses were used to compare survival and death distributions and differences between indices. A total of 143 cases with 90 survivors and 53 deaths were investigated.@*RESULTS@#Average age (Odds Ratio (OR) = 1.036, 95% Confidence Interval (CI) = 1.016-1.057), interval days between dates of onset and confirmation (OR = 1.078, 95% CI = 1.004-1.157), interval days between onset and oseltamivir treatment (OR = 5.923, 95% CI = 1.877-18.687), body temperature (BT) (OR = 3.612, 95% CI = 1.914-6.815), white blood cell count (WBC) (OR = 1.212, 95% CI = 1.092-1.346) were significantly associated with H7N9 death after adjusting for confounders. The chance of death from H7N9 infection was 80.0% if BT was over 38.1 °C, and chance of death is 67.4% if WBC count was higher than 9.5 (10/L). Only 27.1% of patients who began oseltamivir treatment less than 9.5 days after disease onset died, compared to 68.8% of those who started treatment more than 15.5 days after onset.@*CONCLUSIONS@#The intervals between date of onset and confirmation of diagnosis, between date of onset to oseltamivir treatment, age, BT and WBC are found to be the best predictors of H7N9 mortality.

Identification, sequence analysis, and infectivity of H9N2 avian influenza viruses isolated from geese

The subtype H9N2 avian influenza virus greatly threatens the Chinese poultry industry, even with annual vaccination. Waterfowl can be asymptomatically infected with the H9N2 virus. In this study, three H9N2 virus strains, designated A/Goose/Jiangsu/YZ527/2011 (H9N2, Gs/JS/YZ527/11), A/Goose/Jiangsu/SQ119/2012 (H9N2, Gs/JS/SQ119/12), and A/Goose/Jiangsu/JD564/2012 (H9N2, Gs/JS/JD564/12), were isolated from domestic geese. Molecular characterization of the three isolates showed that the Gs/JS/YZ527/11 virus is a double-reassortant virus, combining genes of A/Quail/Hong Kong/G1/97 (H9N2, G1/97)-like and A/Chicken/Shanghai/F/98 (H9N2, F/98)-like; the Gs/JS/SQ119/12 virus is a triple-reassortant virus combining genes of G1/97-like, F/98-like, and A/Duck/Shantou/163/2004 (H9N2, ST/163/04)-like. The sequences of Gs/JS/JD564/12 share high homology with those of the F/98 virus, except for the neuraminidase gene, whereas the internal genes of Gs/JS/YZ527/11 and Gs/JS/SQ119/12 are closely related to those of the H7N9 viruses. An infectivity analysis of the three isolates showed that Gs/JS/SQ119/12 and Gs/JS/YZ527/11 replicated well, with seroconversion, in geese and chickens, the Gs/JS/JD564/12 did not infect well in geese or chickens, and the F/98 virus only infected chickens, with seroconversion. Emergence of these new reassortant H9N2 avian influenza viruses indicates that these viruses can infect both chicken and goose and can produce different types of lesions in each species.

Hospital-based Influenza Morbidity and Mortality (HIMM) Surveillance for A/H7N9 Influenza Virus Infection in Returning Travelers

Since 2013, the Hospital-based Influenza Morbidity and Mortality (HIMM) surveillance system began a H7N9 influenza surveillance scheme for returning travelers in addition to pre-existing emergency room (ER)-based influenza-like illness (ILI) surveillance and severe acute respiratory infection (SARI) surveillance. Although limited to eastern China, avian A/H7N9 influenza virus is considered to have the highest pandemic potential among currently circulating influenza viruses. During the study period between October 1st, 2013 and April 30th, 2016, 11 cases presented with ILI within seven days of travel return. These patients visited China, Hong Kong, or neighboring Southeast Asian countries, but none of them visited a livestock market. Seasonal influenza virus (54.5%, 6 among 11) was the most common cause of ILI among returning travelers, and avian A/H7N9 influenza virus was not detected during the study period.

Avian influenza viruses (AIVs) H9N2 are in the course of reassorting into novel AIVs / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In 2013, two episodes of influenza emerged in China and caused worldwide concern. A new H7N9 avian influenza virus (AIV) first appeared in China on February 19, 2013. By August 31, 2013, the virus had spread to ten provinces and two metropolitan cities. Of 134 patients with H7N9 influenza, 45 died. From then on, epidemics emerged sporadically in China and resulted in several victims. On November 30, 2013, a 73-year-old woman presented with an influenza-like illness. She developed multiple organ failure and died 9 d after the onset of disease. A novel reassortant AIV, H10N8, was isolated from a tracheal aspirate specimen that was obtained from the patient 7 d after onset. This case was the first human case of influenza A subtype H10N8. On 4 February, 2014, another death due to H10N8 avian influenza was reported in Jiangxi Province, China.

Semi-quantitative risk assessment of human infection with H7N9 avian influenza epidemic in Zhejiang province / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the risk of local outbreaks of H7N9 avian influenza infection in Zhejiang province and to explore the semi-quantitative assessment method for public health risks in emergency.</p><p><b>METHODS</b>Risk index system of human infection with H7N9 avian influenza caused by local transmission were reviewed. The weights of indexes were calculated by analytic hierarchy process, which was combined with the TOPSIS method to calculate the risk comprehensive index.</p><p><b>RESULTS</b>Four primary indexes and 23 secondary indexes were identified for risk assessment in local outbreaks of H7N9 avian influenza infection. The weights ranked on the top five were:morbidity (0.0972), closure measures (0.0718), sterilization measures (0.0673), fatality rate (0.0651), and epidemic spread (0.0616). The comprehensive index of the risk of local outbreaks of H7N9 avian influenza ranged from high to low were Hangzhou (0.5910), Shaoxing (0.5711), Jiaxing (0.5199), Taizhou (0.5198), Huzhou (0.4662), Ningbo (0.3828), Wenzhou (0.3719), Jinhua (0.3392), Lishui (0.2727), Quzhou (0.2001) and Zhoushan (0.0508).</p><p><b>CONCLUSIONS</b>A semi-quantitative method has been established in this study, which provides scientific basis for prevention and control of H7N9 avian influenza epidemic in Zhejiang province.</p>

Cardiac complications associated with the influenza viruses A subtype H7N9 or pandemic H1N1 in critically ill patients under intensive care

Abstract Background and objective: The clinical presentations and disease courses of patients hospitalized with either influenza A virus subtype H7N9 (H7N9) or 2009 pandemic H1N1 influenza virus were compared in a recent report, but associated cardiac complications remain unclear. The present retrospective study investigated whether cardiac complications in critically ill patients with H7N9 infections differed from those infected with the pandemic H1N1 influenza virus strain. Methods: Suspect cases were confirmed by reverse transcription polymerase chain reaction assays with specific confirmation of the pandemic H1N1 strain at the Centers for Disease Control and Prevention. Comparisons were conducted at the individual-level data of critically ill patients hospitalized with H7N9 (n = 24) or pandemic H1N1 influenza virus (n = 22) infections in Suzhou, China. Changes in cardiac biochemical markers, echocardiography, and electrocardiography during hospitalization in the intensive care unit were considered signs of cardiac complications. Results: The following findings were more common among the H7N9 group relative to the pandemic H1N1 influenza virus group: greater tricuspid regurgitation pressure gradient, sinus tachycardia (heartbeat ≥ 130 bpm), ST segment depression, right ventricular dysfunction, and elevated cardiac biochemical markers. Pericardial effusion was more often found among pandemic H1N1 influenza virus patients than in the H7N9 group. In both groups, most of the cardiac complications were detected from day 6 to 14 after the onset of influenza symptoms. Those who developed cardiac complications were especially vulnerable during the first four days after initiation of mechanical ventilation. Cardiac complications were reversible in the vast majority of discharged H7N9 patients. Conclusions: Critically ill hospitalized H7N9 patients experienced a higher rate of cardiac complications than did patients with 2009 pandemic H1N1 influenza virus infections, with the exception of pericardial effusion. This study may help in the prevention, identification, and treatment of influenza-induced cardiac complications in both pandemic H1N1 influenza virus and H7N9 infections.

Characterization of Avian Influenza A (H7N9) Virus Prevalence in Humans and Poultry in Huai'an, China: Molecular Epidemiology, Phylogenetic, and Dynamics Analyses / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.</p><p><b>METHODS</b>An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an. Clinical specimens, cloacal swabs, and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction (RT-PCR) for H7N9 virus. The positive samples were subjected to further RT-PCR and genome sequencing. The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.</p><p><b>RESULTS</b>Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever (>38.0 °C) and headaches. Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure. Phylogenetic analysis revealed that all novel H7N9 viruses, including Huai'an strains, could be classified into two distinct clades, A and B. Additionally, the diversified H7N9 virus circulated in live poultry markets in Huai'an. Interestingly, the common ancestors of the Huai'an H7N9 virus existed in January 2012. The mean nucleotide substitution rates for each gene segment of the H7N9 virus were (3.09-7.26)×10-3 substitutions/site per year (95% HPD: 1.72×10-3 to 1.16×10-2).</p><p><b>CONCLUSION</b>Overall, the source of exposure of human H7N9 cases in Huai'an was live poultry market, and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.</p>

H9N2 influenza virus in China: a cause of concern

The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface might be due to the wide host range, adaptation in both poultry and mammalian, and extensive gene reassortment. As the most prevalent subtype of influenza viruses in chickens in China, H9N2 also causes a great economic loss for the poultry industry, even under the long-term vaccination programs. The history, epidemiology, biological characteristics, and molecular determinants of H9N2 influenza virus are reviewed in this paper. The contribution of H9N2 genes, especially RNP genes, to the infection of humans needs to be investigated in the future.

The negative psychology for the public in Zhejiang province during the epidemic of human H7N9 avian influenza / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the cognition and emotional response of the public in Zhejiang province during the epidemic of human H7N9 avian influenza and provide scientific support for group psychological intervention under public health emergency.</p><p><b>METHODS</b>57 communities in 19 counties from Hangzhou, Jiaxing and Lishui district of Zhejiang province were selected as survey sites using stratified clustered sampling method from March, 2013 to April, 2014. 2 319 ordinary civilians were chosen using convenience sampling method and 390 individuals who had close contact history with H7N9 avian influenza patients, 109 family members of patients and 281 medical workers, were selected using census method. The inclusion criteria for subjects were: subjects aged over 10 years; could complete the questionnaire independently or with the help of the investigators. A total of 2 709 subjects were surveyed by avian influenza risk perception and response questionnaire, negative emotion questionnaire was also used to see their cognition and negative emotion related to the disease. Spearman correlation analysis was used to analyze the interrelationship between public risk perception, response and negative emotions.</p><p><b>RESULTS</b>95.10% (2 576)of the subjects have sensed the risk of epidemic and 91.00% (2 465) of the subjects have taken preventive measures in 2 709 subjects. The positive rate for depression, neurasthenia, fear, anxiety and hypochondriasis were 36.40% (986) , 37.21% (1 008) , 79.70% (2 159) , 33.41% (905) , 27.69% (750) respectively (χ(2)=1 935.89, P<0.001) ;the P(50)(P(25)-P(75)) of the depression scores of patients' family members, medical workers and the general public were 0.50 (0.00-0.83), 0.17 (0.00-0.67), 0.17 (0.00-0.50) (H= 7.27, P=0.03) ; the neurasthenia scores were 0.20 (0.00-0.60), 0.2 (0.00-0.40), 0.00 (0.00-0.20) (H= 64.74, P<0.001) ; fear scores were 0.83 (0.33-1.17), 0.33 (0.17-0.67), 0.33 (0.17-0.83) (H=30.03, P< 0.001) ; anxiety scores were 0.17(0.00-0.50), 0.00(0.00-0.33), 0.00(0.00-0.17) (H=51.82, P<0.001). The neurasthenia, fear, anxiety scores (P(50)(P(25)-P(75))) for females among the public were 0.00(0.00-0.20), 0.50(0.17-0.83), 0.00(0.00-0.17), which were higher than those of male's (0.00(0.00-0.20), 0.33(0.00-0.67), 0.00(0.00-0.17)) (χ(2) values were 5.26, 27.52, 8.29, P<0.05); Among medical staff, the depression, neurasthenia, fear, anxiety and hypochondriasis scores for females were 0.33(0.00-0.67), 0.20(0.00-0.40), 0.50(0.17-0.83), 0.00(0.00-0.33), 0.00(0.00-0.50) respectively, which were higher than those of males'(0.00(0.00-0.50), 0.00(0.00-0.40), 0.33(0.17-0.50), 0.00(0.00-0.17), 0.00(0.00-0.00))(χ(2) values were 7.22, 7.97, 14.46, 4.93, 5.22, P<0.05); for the family members of the patients who were in poor mental conditions when doing self-assessment, their depression and neurasthenia scores were 0.50(0.08-0.96), 0.30(0.00-0.55), which were higher than those of people in good mental conditions (0.17(0.00-0.83), 0.20(0.00-0.60)) (χ(2) values were 12.95, 11.20, P<0.05). Spearman correlation analysis showed that the subjects' risk perception level was positively correlated with depression, neurasthenia, fear, and hypochondriasis, with the correlation coefficients 0.07, 0.07, 0.08, 0.04, respectively (P<0.05) ; the subjects' risk response level was also positively related with depression, neurasthenia, fear, anxiety and hypochondriasis, and the correlation coefficients were 0.09, 0.09, 0.12, 0.05, 0.04, respectively (P<0.05).</p><p><b>CONCLUSION</b>The general public was highly concerned about the epidemic of H7N9 avian influenza and developed certain levels of negative emotions. The female, equal or over 60 years old, those with poor educational level, agricultural related occupation and poor physical and psychology health were risk factors of disease related negative emotions. The subject's risk perception and response level was positively related with depression, neurasthenia, fear and hypochondriasis.</p>

Determination of Influenza Virus H5N1 and H7N9 Using MASA Technology / 病毒学报

To set up a new rapid method for the rapid determination of influenza virus H5N1 and H7N9 basing on the Multi-Analyte Suspension Array (MASA) technology. Sequence analysis and design of degenerate primers and specific probes were set in the comparison and analysis of H5, N1, H7 and N9 genes. In combination with MASA technology, these primers and probes were used for the determination of samples of H5N1 and H7N9 and other subtypes ( H1N1, PH1N1, H5N2, H3N2 and H9N2). We developed a rapid determination method. This method had high specificity and sensitivity that could detect H5N1 and H7N9 at one time, and could detect samples that containing 10 copies of H5N1 and H7N9. This determination method could be used for rapid determination of influenza virus H5N1 and H7N9 at one time.

Analysis of the Genetic Evolution of Neuraminidases of Influenza A Subtype N9 Viruses / 病毒学报

This study analyzed the genetic evolution of neuraminidases (NAs) of influenza A subtype N9 viruses with the aim of determining the genetic origin of the novel avian A/H7N9 influenza virus. The NA sequences of influenza A subtype N9 viruses available from NCBI were used to construct a phylogenetic tree using the programs ClustalX 2.0 and MEGA 6.0. This analysis indicated that the novel avian A/H7N9 influenza virus is located in the modern Eurasian phylogenetic cluster. This cluster was then further analyzed by estimating the overall rate of evolutionary change and the selective pressure at the nucleotide level using the program BEAST 2.1.2 and the web interface Datamonkey, and by generating an amino acid sequence entropy plot using Bioedit software. In this cluster, the mean rate of nucleotide substitutions in NA was found to be 3.8354 x 10(-3) and the mean ratio of non-synonymous (dN) to synonymous (dS) substitutions per site (dN/dS) was 0.140413. A particularly high level of amino acid mutation entropy was identified at nucleotides 16, 19, 40, 53, 81, 84, 112, 256, 335, 359, and 401. This genetic evolution analysis suggests that the nucleotide substitutions that characterize the novel avian A/H7N9 influenza virus neuraminidase are likely to result from the overall genetic evolution of influenza A subtype N9 virus NAs, and not from selective stress. Phylogenetic analysis suggests that the influenza A virus (A/duck/Siberia/700/1996(H11N9)) isolated in 1996 appears to be the common ancestor of the more recent influenza A subtype N9 viruses NAs.

Predicating risk area of human infection with avian influenza A (H7N9) virus by using early warning model in China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish a risk early warning model of human infection with avian influenza A (H7N9) virus and predict the area with high risk of the outbreak of H7N9 virus infection.</p><p><b>METHODS</b>The incidence data of human infection with H7N9 virus at prefecture level in China from February 2013 to June 2014 were collected, and the geographic and meteorological data during the same period in these areas were collected too. Spatial auto regression (SAR) model and generalized additive model (GAM) were used to estimate different risk factors. Afterwards, the risk area map was created based on the predicted value of both models.</p><p><b>RESULTS</b>All the human infections with H7N9 virus occurred in the predicted areas by the early warning model in February 2014. The early warning model successfully predicted the spatial moving trend of the disease, and this trend was verified by two outbreaks in northern China in April and May 2014.</p><p><b>CONCLUSION</b>The established early warning model showed accuracy and precision in short-term prediction, which might be applied in the active surveillance, early warning and prevention/control of the outbreak of human infection with H7N9 virus.</p>

Investigation of a family clustering of human infection with avian influenza A (H7N9) virus in Nanning, Guangxi / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand the transmission mode of human infection with avian influenza A (H7N9) virus.</p><p><b>METHODS</b>Field epidemiological investigation was conducted for a family clustering of human infection with H7N9 virus in Hengxian county, Guangxi Zhuang Autonomous Region in February 2014. Two patients and their 82 close contacts were surveyed. The samples collected from the patients, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (rRT-PCR), and the samples from patients were used for virus isolation. The samples from 5 close contacts were tested with RT-PCR. The clinical data, exposure histories of the patients and the detection results of the isolates and their homology were analyzed.</p><p><b>RESULTS</b>Patient A became ill 4 days after her last exposure to poultry in Zhongshan, Guangdong province, and returned to her hometown in Hengxian 2 days after onset. Patient B was patient A's 5 years old son, who had no known exposure to poultry but slept with patient A for 4 days. He developed symptoms 4 days after last contact with his mother. Two strains of H7N9 virus were isolated from the two patients. The 2 isolates were highly homogenous (almost 100%) indicated by gene sequencing and phylogenetic tree. None of the other 81 close contacts developed symptoms of H7N9 virus infection.</p><p><b>CONCLUSION</b>Patients B was infected through close contact with patient A, indicating that avian H7N9 virus can spread from person to person, but the transmissibility is limited and non-sustainable.</p>

Acceptance and influence factor of central slaughtering of live poultry in residents of Guangzhou / 中华预防医学杂志

<p><b>OBJECTIVES</b>To investigate a survey about acceptance of central slaughtering of live poultry in residents of Guangzhou.</p><p><b>METHODS</b>We conducted a telephone survey by sampling residents with fixed-line telephone and with normal hearing, whose age is more than 15 years, by Mitofsky-Waksberg two-stage method during Jan 6(th) to 8(th), 2014. 358 residents finished the telephone questionnaire by 12 320 health hot line. We investigated the acceptance rate of city-wide central slaughtering permanently. We compared the difference between the respondents and the 2010 Guangzhou census data by Cohen's effect sizes (w) and weighted by population age and sex. We used χ(2) test to compare the acceptance rate of central slaughtering in residents with different characteristic. We used multiple logistic regression analysis to analyze the factors.</p><p><b>RESULTS</b>The difference in gender and age was small between respondents and the 2010 Guangzhou census data (w value was 0.13, 0.28, respectively), but that in education and marital status was large (w value was 0.52, 0.31, respectively). 49.0% (95% CI: 43.7%-54.3%) accept city-wide central slaughtering permanently. The acceptance rate of city-wide central slaughtering permanently in those who bought fresh, chilled and frozen poultry in their family in previous year was 54.3% (133/245), 60.0% (57/95) and 59.8% (49/82), respectively. It was more than those who didn't buy fresh, chilled and frozen poultry (38.1% (43/113), 44.9% (118/263) and 45.7% (126/276); χ(2) values were 8.15, 6.40 and 5.03; P values were 0.004, 0.011 and 0.025, respectively). The acceptance rate of city-wide central slaughtering permanently in those who deem fresh poultry taste better than live poultry was 64.9% (24/38). It more than those who deem not (47.0%, 151/320) (χ(2) = 4.22, 6.02, P = 0.040, 0.014, respectively). The acceptance rate of city-wide central slaughtering permanently in the male (OR = 2.68, 95% CI: 1.64-4.37) and those who deem getting sick due to buying live birds from LPM (OR = 1.72, 95% CI: 1.05-2.82), who can accept only fresh poultry carcass supply (OR = 2.39, 95% CI: 1.33-4.30), Who bought live poultry in their family in previous year (OR = 0.29, 95% CI: 0.11-0.74), who will decrease the consumption after ban on live poultry sale (OR = 0.50, 95% CI: 0.30-0.83) was 58.6% (109/186), 59.0% (92/156), 60.7% (139/230), 44.9% (132/295), 36.6% (68/186), respectively.</p><p><b>CONCLUSION</b>In the early stage of avian influenza A(H7N9) epidemic in Guangzhou, the rate of acceptance of central slaughtering permanently in residents was not so high. Who deem getting sick due to buying live birds from LPM, who could accept only fresh poultry carcass supply and the male more accept city-wide central slaughtering permanently.</p>

Epidemiological characteristics of human avian influenza A (H7N9) virus infection in China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the epidemiological characteristics of human infections with avian influenza A (H7N9) in China and to provide scientific evidence for the adjustment of preventive strategy and control measures.</p><p><b>METHODS</b>Demographic and epidemiologic information on human cases were collected from both reported data of field epidemiological investigation and the reporting system for infectious diseases.</p><p><b>RESULTS</b>A total of 433 cases including 163 deaths were reported in mainland China before June 4, 2014. Two obvious epidemic peaks were noticed, in March to April, 2013 and January to February, 2014. Confirmed cases emerged in 14 areas of China. Five provinces, including Zhejiang, Guangdong, Jiangsu, Shanghai, and Hunan, reported about 85% of the total cases. Median age of the confirmed cases was 58 years (range, 1-91), with 70% as males. Of the 418 cases with available data, 87% had ever exposed to live poultry or contaminated environments. 14 clusters were identified but human to human transmission could not be ruled out in 9 clusters.</p><p><b>CONCLUSION</b>Human infections with avian influenza A (H7N9) virus showed the characteristics of obvious seasonal distribution, with certain regional clusters. The majority of confirmed cases were among the elderly, with more males seen than the females. Data showed that main source of infection was live poultry and the live poultry market had played a significant role in the transmission of the virus.</p>