The diversity of avian influenza virus subtypes in live poultry markets before and during the second wave of A(H7N9) infections in Hangzhou, China.
Ontology highlight
ABSTRACT:
SUBMITTER: Li J
PROVIDER: S-EPMC4345288 | biostudies-literature | 2015 Feb
REPOSITORIES: biostudies-literature
Publications
The diversity of avian influenza virus subtypes in live poultry markets before and during the second wave of A(H7N9) infections in Hangzhou, China.
Li Jun J Yu Xinfen X Pu Xiaoying X Yang Xuhui X Kou Yu Y Zhou Yinyan Y Qian Xin X Xie Li L Pan Jingcao J
Emerging microbes & infections 20150225 2
Similar Datasets
Project description:BackgroundTo provide an increased understanding of avian influenza A(H7N9) activity in live-poultry market in space and time and hence improve H7N9 epidemic control, an ongoing environmental sampling program in multiple live-poultry markets across Guangdong, China was conducted during March 2013-June 2014.MethodsA total of 625 live-poultry markets throughout 21 prefecture areas took part in the study. A total of 10 environmental sites in markets for sampling were identified to represent 4 different poultry-related activity areas. At least 10 environmental samples were collected from each market every month. The real time RT-PCR was performed to detect the avian influenza A(H7N9) virus. Field survey was conducted to investigate the sanitation status of live-poultry markets.ResultsThere were 109 human infections with H7N9 avian influenza in Guangdong, of which 37 (34%) died. A total of 18741 environmental swabs were collected and subjected to real-time RT-PCR test, of which 905(4.83%) were found positive for H7N9 virus. There were 201 (32.16%) markets affected by H7N9 in 16 prefecture areas. The detection of H7N9 virus in markets spiked in winter months. 63.33% markets (38/60) had no physical segregation for poultry holding, slaughter or sale zones. Closing live-poultry market significantly decreased the H7N9 detection rate from 14.83% (112/755) to 1.67% (5/300).ConclusionsThis study indicates the importance of live-poultry market surveillance based on environmental sampling for H7N9 Avian Influenza control. Improving live-poultry market management and sanitation and changing consumer practices are critical to reduce the risk of H7N9 infection.
| S-EPMC4416787 | biostudies-literature
Project description:Two epidemic waves of an avian influenza A (H7N9) virus have so far affected China. Most human cases have been attributable to poultry exposure at live-poultry markets, where most positive isolates were sampled. The potential geographic extent of potential re-emerging epidemics is unknown, as are the factors associated with it. Using newly assembled data sets of the locations of 8,943 live-poultry markets in China and maps of environmental correlates, we develop a statistical model that accurately predicts the risk of H7N9 market infection across Asia. Local density of live-poultry markets is the most important predictor of H7N9 infection risk in markets, underscoring their key role in the spatial epidemiology of H7N9, alongside other poultry, land cover and anthropogenic predictor variables. Identification of areas in Asia with high suitability for H7N9 infection enhances our capacity to target biosurveillance and control, helping to restrict the spread of this important disease.
| S-EPMC4061699 | biostudies-literature
Project description:In the last two decades, two important avian influenza viruses infecting humans emerged in China, the highly pathogenic avian influenza (HPAI) H5N1 virus in the late nineties, and the low pathogenic avian influenza (LPAI) H7N9 virus in 2013. China is home to the largest population of chickens (4.83 billion) and ducks (0.694 billion), representing, respectively 23.1 and 58.6% of the 2013 world stock, with a significant part of poultry sold through live-poultry markets potentially contributing to the spread of avian influenza viruses. Previous models have looked at factors associated with HPAI H5N1 in poultry and LPAI H7N9 in markets. However, these have not been studied and compared with a consistent set of predictor variables. Significant progress was recently made in the collection of poultry census and live-poultry market data, which are key potential factors in the distribution of both diseases. Here we compiled and reprocessed a new set of poultry census data and used these to analyse HPAI H5N1 and LPAI H7N9 distributions with boosted regression trees models. We found a limited impact of the improved poultry layers compared to models based on previous poultry census data, and a positive and previously unreported association between HPAI H5N1 outbreaks and the density of live-poultry markets. In addition, the models fitted for the HPAI H5N1 and LPAI H7N9 viruses predict a high risk of disease presence for the area around Shanghai and Hong Kong. The main difference in prediction between the two viruses concerned the suitability of HPAI H5N1 in north-China around the Yellow sea (outlined with Tianjin, Beijing, and Shenyang city) where LPAI H7N9 has not spread intensely.
| S-EPMC5329093 | biostudies-literature
Project description:BackgroundTo date, there have been a total of 637 laboratory-confirmed cases of human infection with avian influenza A (H7N9) virus across mainland China, with 28% (179/637) of these reported in Zhejiang Province. Surveillance of avian H7N9 virus was conducted to investigate environmental contamination during H7N9 outbreaks. We sought to evaluate the prevalence of H7N9 in the environment, and the effects of poultry market closures on the incidence of human H7N9 cases.MethodsWe collected 6740 environmental samples from 751 sampling sites across 11 cities of Zhejiang Province (China) between January 2013 and March 2014. The presence of H7N9 was determined by reverse transcription polymerase chain reaction, with prevalence compared between sites and over time. The relationship between environmental contamination and human cases of H7N9 infection were analyzed using Spearman's ranked correlation coefficient.ResultsOf the 6740 samples, 10.09% (680/6740) were H7N9-positive. The virus was found to circulate seasonally, and peaked during the spring and winter of 2013-2014. The prevalence of the virus decreased from the north to the southeast of the province, coinciding with the geographical distribution of human H7N9 cases. Compared with other sampling sites, live poultry markets (LPMs) had the highest prevalence of H7N9 virus at 13.94% (667/4784). Of the various sample types analyzed, virus prevalence was highest for chopping board swabs at 15.49% (110/710). The prevalence of the virus in the environment positively correlated with the incidence of human H7N9 cases (r2 = 0.498; P < 0.01). Cities with a higher incidence of human H7N9 cases also had a higher prevalence of H7N9 among samples and at sampling sites. Following the closure of LPMs at the end of January 2014, the prevalence of H7N9 decreased from 19.18% (487/2539) to 6.92% (79/1141). This corresponded with a decrease in the number of human H7N9 cases reported.ConclusionsThe prevalence of H7N9 virus in environmental samples oscillated seasonally, regardless of whether LPMs were open. The presence of H7N9 in environmental samples positively correlated with the number of human H7N9 cases, indicating that eradication of the virus from the environment is essential in reducing the numbers of H7N9 cases and halting the spread of the virus.
| S-EPMC4550274 | biostudies-literature
Project description:PurposeA virologic surveillance program for A(H7N9) virus was conducted from April 15, 2013 to February 14, 2014 in Guangzhou, aiming to clarify the geographical distribution of A(H7N9) viruses among live poultry markets (LPMs) and poultry farms in Guangzhou. Virological and serological surveys of poultry workers were also conducted to evaluate the risk of poultry-to-human transmission of the A(H7N9) virus.Methods36 retail LPMs, 6 wholesale LPMs and 8 poultry farms were involved in our surveillance program. About 20 live poultry and environmental samples were obtained from each surveillance site at every sampling time. Different environmental samples were collected to represent different poultry-related work activities. RT-PCR and virus culture were performed to identify the A(H7N9) virus. Hemagglutinin inhibition assay and RT-PCR were conducted to detect possible A(H7N9) infection among poultry workers.ResultsA total of 8900 live poultry and environmental samples were collected, of which 131(1.5%) were tested positive for A(H7N9) virus. 44.4% (16/36) of retail LPMs and 50.0% (3/6) of wholesale LPMs were confirmed to be contaminated. No positive samples was detected from poultry farms. A significant higher positive sample rate was found in environmental samples related to poultry selling (2.6%) and slaughtering (2.4%), compared to poultry holding (0.9%). Correspondingly, A(H7N9) viruses were isolated most frequently from slaughter zone. In addition, 316 poultry workers associated with the 19 contaminated-LPMs were recruited and a low seroprevalence (1.6%) of antibody against A(H7N9) virus was detected. An asymptomatic A(H7N9) infection was also identified by RT-PCR.ConclusionsOur study highlights the importance of conducting effective surveillance for A(H7N9) virus and provides evidence to support the assumption that slaughtering is the key process for the propagation of A(H7N9) virus in retail LPMs. Moreover, the ability of A(H7N9) virus to cross species barrier is proved to be still limited.
| S-EPMC4162608 | biostudies-literature
Project description:BackgroundTransmission of the novel avian influenza A H7N9 virus seems to be predominantly between poultry and people. In the major Chinese cities of Shanghai, Hangzhou, Huzhou, and Nanjing--where most human cases of infection have occurred--live poultry markets (LPMs) were closed in April, 2013, soon after the initial outbreak, as a precautionary public health measure. Our objective was to quantify the effect of LPM closure in these cities on poultry-to-person transmission of avian influenza A H7N9 virus.MethodsWe obtained information about every laboratory-confirmed human case of avian influenza A H7N9 virus infection reported in the four cities by June 7, 2013, from a database built by the Chinese Center for Disease Control and Prevention. We used data for age, sex, location, residence type (rural or urban area), and dates of illness onset. We obtained information about LPMs from official sources. We constructed a statistical model to explain the patterns in incidence of cases reported in each city on the basis of the assumption of a constant force of infection before LPM closure, and a different constant force of infection after closure. We fitted the model with Markov chain Monte Carlo methods.Findings85 human cases of avian influenza A H7N9 virus infection were reported in Shanghai, Hangzhou, Huzhou, and Nanjing by June 7, 2013, of which 60 were included in our main analysis. Closure of LPMs reduced the mean daily number of infections by 99% (95% credibility interval 93-100%) in Shanghai, by 99% (92-100%) in Hangzhou, by 97% (68-100%) in Huzhou, and by 97% (81-100%) in Nanjing. Because LPMs were the predominant source of exposure to avian influenza A H7N9 virus for confirmed cases in these cities, we estimated that the mean incubation period was 3·3 days (1·4-5·7).InterpretationLPM closures were effective in the control of human risk of avian influenza A H7N9 virus infection in the spring of 2013. In the short term, LPM closure should be rapidly implemented in areas where the virus is identified in live poultry or people. In the long term, evidence-based discussions and deliberations about the role of market rest days and central slaughtering of all live poultry should be renewed.FundingMinistry of Science and Technology, China; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; and the US National Institutes of Health.
| S-EPMC3946250 | biostudies-literature
Project description: Not available
| S-EPMC4631930 | biostudies-literature
Project description:We analyzed ≈ 12 years of surveillance data on avian influenza in Hong Kong live poultry markets. A ban on keeping live poultry overnight in these markets reduced virus isolation rates by 84% in chickens (p = 0.006) and 100% (p = 0.01) in minor poultry.
| S-EPMC3414033 | biostudies-literature
Project description:We report the use of environmental samples to assess avian influenza virus activity in chickens at live poultry markets in China. Results of environmental and chicken samples correlate moderately well. However, collection of multiple environmental samples from holding, processing, and selling areas is recommended to detect viruses expected to have low prevalence.
| S-EPMC7045814 | biostudies-literature
Project description:Zoonotic infections by avian influenza viruses occur at the human-poultry interface, but the modes of transmission have not been fully investigated. We assessed the potential for airborne and fomite transmission at live poultry markets in Guangzhou city and in Hong Kong Special Administrative Region (SAR), China, during 2014 and 2015. Viral genome and infectious avian influenza A viruses of H5N6, H7N9, and H9N2 subtypes were detected predominantly from particles larger or equal to 1 ?m in diameter in the air sampled with cyclone-based bioaerosol samplers at the live poultry markets in Guangzhou. Influenza A(H9N2) viruses were ubiquitously isolated every month during the study period from air and environmental swabs, and different lineages of H9N2 virus were isolated from markets where chickens and minor land-based poultry were sold. The use of de-feathering devices increased the quantity of virus-laden airborne particles while market closure reduced the amount of such particles. The results highlight the possibility of airborne transmission of avian influenza viruses among poultry or from poultry to humans within such settings. This may explain epidemiological observations in which some patients with H7N9 infection reported being in markets but no direct contact with live poultry or poultry stalls.
| S-EPMC5015459 | biostudies-literature