Avian Influenza Virus Detection Rates in Poultry and Environment at Live Poultry Markets, Guangdong, China.
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ABSTRACT:
SUBMITTER: Cheng KL
PROVIDER: S-EPMC7045814 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:To 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.A 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.There 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).This 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:Since early 2013, H7N9-subtype avian influenza virus (AIV) has caused human infection in eastern China. To evaluate AIV contamination and the public risk of infection, we systematically implemented environmental sampling from live poultry markets in Guangdong Province. Through real-time polymerase chain reaction assays and next-generation sequencing, we generated full nucleotide sequences of all 10 H6N6 AIVs isolated during sampling. Focusing on sequence analyses of hemagglutinin genes of the 10 H6N6 AIVs revealed that the viruses were low pathogenic AIVs with the typical hemagglutinin cleavage site of P-Q-I-E-T-R-G. The hemagglutinin, neuraminidase, and nucleocapsid genes of nine AIVs were of ST2853-like (H6-subtype) lineage, ST192-like (N6-subtype) lineage, and HN573-like (H6-subtype) lineage, respectively; whereas the other five genes were of ST339-like (H6-subtype) lineage. However, the polymerase PB2 and nucleocapsid genes of one strain (HZ057) were of GS/GD-like (H5N1-subtype) and ST339-like lineages. Phylogenic analysis revealed that all eight genes of the 10 viruses belonged to Eurasian avian lineage. Altogether, the 10 AIVs were reassortants of different genetic groups of exchanges with the same virus subtype, thus illustrating the genetic diversity and complexity of H6N6-subtype AIVs in Guangdong Province.
| S-EPMC4742543 | biostudies-literature
Project description:H9N2 avian influenza viruses (AIVs) are highly prevalent and of low pathogenicity in domestic poultry. These viruses show a high genetic compatibility with other subtypes of AIVs and have been involved in the genesis of H5N1, H7N9 and H10N8 viruses causing severe infection in humans. The first case of human infection with H9N2 viruses in Hunan province of China have been confirmed in November 2013 and identified that H9N2 viruses from live poultry markets (LPMs) near the patient's house could be the source of infection. However, the prevalence, distribution and genetic characteristics of H9N2 viruses in LPMs all over the province are not clear. We collected and tested 3943 environmental samples from 380 LPMs covering all 122 counties/districts of Hunan province from February to April, 2014. A total of 618 (15.7%) samples were H9 subtype positive and 200 (52.6%) markets in 98 (80.3%) counties/districts were contaminated with H9 subtype AIVs. We sequenced the entire coding sequences of the genomes of eleven H9N2 isolates from environmental samples. Phylogenetic analysis showed that the gene sequences of the H9N2 AIVs exhibited high homology (94.3%-100%). All eleven viruses were in a same branch in the phylogenetic trees and belonged to a same genotype. No gene reassortment had been found. Molecular analysis demonstrated that all the viruses had typical molecular characteristics of contemporary avian H9N2 influenza viruses. Continued surveillance of AIVs in LPMs is warranted for identification of further viral evolution and novel reassortants with pandemic potential.
| S-EPMC4640513 | biostudies-literature
Project description:A 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.36 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.A 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.Our 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:BackgroundAvian influenza viruses have caused human infection and posed the pandemic potential. Live poultry markets are considered as a source of human infection with avian influenza viruses. Avian influenza routine surveillance of live poultry markets is taken annually in China. We isolated the 2 H11N9 influenza virus from the surveillance program. To better understand the risk caused by these new viruses, we characterize the genetic and pathogenicity of the two viruses.MethodsViral isolation was conducted with specific pathogen-free (SPF) embryonated chicken eggs. Whole genome was sequenced, and phylogenetic analysis was conducted.ResultsTwo H11N9 viruses were identified, with all 8 segments belonging to the Eurasian lineage. The HA, NA, M, NS and PA genes were similar to virus isolates from ducks, and the NP, PB2 and PB1 gene segments were most similar to those viruses from wild birds, indicating that the H11N9 viruses might represent reassortant viruses from poultry and wild birds. The HA receptor binding preference was avian-like, and the cleavage site sequence of HA showed low pathogenic. The NA gene showed 94.6 % identity with the novel H7N9 virus that emerged in 2013. There was no drug resistance mutation in the M2 protein. The Asn30Asp and Thr215Ala substitutions in the M1 protein implied a potentially increased pathogenicity in mice. Both viruses were low-pathogenic strains, as assessed by the standards of intravenous pathogenicity index (IVPI) tests.ConclusionTwo reassortant H11N9 avian influenza viruses were detected. These viruses showed low pathogenicity to chickens in the IVPI test. Public health concern caused by the reassortant H11N9 viruses should be emphasized during the future surveillance.
| S-EPMC4897819 | biostudies-literature
Project description:We conducted a 3-year longitudinal serologic survey on an open cohort of poultry workers, swine workers, and general population controls to assess avian influenza A virus (AIV) seroprevalence and seroincidence and virologic diversity at live poultry markets (LPMs) in Wuxi City, Jiangsu Province, China. Of 964 poultry workers, 9 (0.93%) were seropositive for subtype H7N9 virus, 18 (1.87%) for H9N2, and 18 (1.87%) for H5N1. Of 468 poultry workers followed longitudinally, 2 (0.43%), 13 (2.78%), and 7 (1.5%) seroconverted, respectively; incidence was 1.27, 8.28, and 4.46/1,000 person-years for H7N9, H9N2, and H5N1 viruses, respectively. Longitudinal surveillance of AIVs at 9 LPMs revealed high co-circulation of H9, H7, and H5 subtypes. We detected AIVs in 726 (23.3%) of 3,121 samples and identified a high diversity (10 subtypes) of new genetic constellations and reassortant viruses. These data suggest that stronger surveillance for AIVs within LPMs and high-risk populations is imperative.
| S-EPMC6038753 | biostudies-literature
Project description: Not available
| S-EPMC4631930 | 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: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:H3 subtype influenza A virus is one of the main subtypes that threats both public and animal health. However, the evolution and pathogenicity of H3 avian influenza virus (AIV) circulating in domestic birds in China remain largely unclear. In this study, seven H3 AIVs (four H3N2 and three H3N8) were isolated from poultry in live poultry market (LPM) in China. Phylogenetic analyses of full genomes showed that all viruses were clustered into Eurasian lineage, except N8 genes of two H3N8 isolates fell into North American lineage. Intriguingly, the N8 gene of one H3N8 and PB2, PB1, NP and NS of two H3N2 isolates have close relationship with those of the highly pathogenic H5N8 viruses circulating in Korea and United States, suggesting that the H3-like AIV may contribute internal genes to the highly pathogenic H5N8 viruses. Phylogenetic tree of HA gene and antigenic cross-reactivity results indicated that two antigenically different H3 viruses are circulating in LPM in China. Most of the H3 viruses replicated in mice lung and nasal turbinate without prior adaptation, and the representative H3 viruses infected chickens without causing clinical signs. The reassortment of H3 subtype influenza viruses warrants continuous surveillance in LPM in China.
| S-EPMC4895239 | biostudies-literature