Live Poultry Markets Research Articles

Interventions in Live Poultry Markets for the Control of Avian Influenza: A Systematic Review and Meta-analysis.

This review aimed to provide constructive suggestions for the control and management of avian influenza through quantitative and qualitative evaluation of the impact of different live poultry market (LPM) interventions. Both English and Chinese language databases were searched for articles that were published on or before 9 November 2018. After extraction and assessment of the included literature, Stata14.0 was applied to perform a meta-analysis to explore the impacts of LPM interventions. A total of 19 studies were identified. In total, 224 human, 3550 poultry, and 13 773 environment samples were collected before the intervention; 181 people, 4519 poultry, and 9562 environments were sampled after LPM interventions. Avian influenza virus (AIV) detection rates in the LPM environment (odds ratio [OR], 0.393; 95% confidence interval [CI], 0.262-0.589) and the incidence of AIV infection (OR, 0.045; 95% CI, 0.025-0.079) were significantly lower after LPM interventions, while interventions were not significantly effective in reducing AIV detection in poultry samples (OR, 0.803; 95% CI, 0.403-1.597). LPM interventions can reduce AIV human infections and the detection rate of AIV in market environments.

Detection of highly pathogenic avian influenza A(H5N6) viruses in waterfowl in Bangladesh

Bangladesh has reported repeated outbreaks of highly pathogenic avian influenza (HPAI) A(H5) viruses in poultry since 2007. Because of the large number of live poultry markets (LPM) relative to the population density of poultry throughout the country, these markets can serve as sentinel sites for HPAI A(H5) detection. Through active LPM surveillance during June 2016–June 2017, HPAI A(H5N6) viruses along with 14 other subtypes of influenza A viruses were detected. The HPAI A(H5N6) viruses belonged to clade 2.3.4.4 and were likely introduced into Bangladesh around March 2016. Human infections with influenza clade 2.3.4.4 viruses in Bangladesh have not been identified, but the viruses had several molecular markers associated with potential human infection. Vigilant surveillance at the animal-human interface is essential to identify emerging avian influenza viruses with the potential to threaten public and animal health.

Genetic and biological characteristics of avian influenza virus subtype H1N8 in environments related to live poultry markets in China

BackgroundSince 2008, avian influenza surveillance in poultry-related environments has been conducted annually in China. Samples have been collected from environments including live poultry markets, wild bird habitats, slaughterhouses, and poultry farms. Multiple subtypes of avian influenza virus have been identified based on environmental surveillance, and an H1N8 virus was isolated from the drinking water of a live poultry market.MethodsVirus isolation was performed by inoculating influenza A-positive specimens into embryonated chicken eggs. Next-generation sequencing was used for whole-genome sequencing. A solid-phase binding assay was performed to test the virus receptor binding specificity. Trypsin dependence plaque formation assays and intravenous pathogenicity index tests were used to evaluate virus pathogenicity in vitro and in vivo, respectively. Different cell lines were chosen for comparison of virus replication capacity.ResultsAccording to the phylogenetic trees, the whole gene segments of the virus named A/Environment/Fujian/85144/2014(H1N8) were of Eurasian lineage. The HA, NA, PB1, and M genes showed the highest homology with those of H1N8 or H1N2 subtype viruses isolated from local domestic ducks, while the PB2, PA, NP and NS genes showed high similarity with the genes of H7N9 viruses detected in 2017 and 2018 in the same province. This virus presented an avian receptor binding preference. The plaque formation assay showed that it was a trypsin-dependent virus. The intravenous pathogenicity index (IVPI) in chickens was 0.02. The growth kinetics of the A/Environment/Fujian/85144/2014(H1N8) virus in different cell lines were similar to those of a human-origin virus, A/Brisbane/59/2007(H1N1), but lower than those of the control avian-origin and swine-origin viruses.ConclusionsThe H1N8 virus was identified in avian influenza-related environments in China for the first time and may have served as a gene carrier involved in the evolution of the H7N9 virus in poultry. This work further emphasizes the importance of avian influenza virus surveillance, especially in live poultry markets (LPMs). Active surveillance of avian influenza in LPMs is a major pillar supporting avian influenza control and response.

Transmission risk of avian influenza virus along poultry supply chains in Guangdong, China

ObjectivesAvian influenza viruses (AIVs) poise significant risk to human health and the poultry industry. We evaluated the transmission risk along the poultry supply chain. MethodsDuring October 2015 and July 2016, four rounds of cross-sectional surveys were performed to characterize AIV spread in farms, transport vehicles, slaughterhouses, wholesale and retail live poultry markets (LPMs). Poultry cloacal and oral swabs, environmental swabs, bioaerosol samples and human sera were collected. Poultry and environmental samples were tested for AIVs by rRT-PCR, further subtyped by next generation sequencing. Previous human H9N2 infections were identified by hemagglutination inhibition and microneutralization tests. Logistic regression was fitted to compare AIV transmission risk in different settings. ResultsAIVs was detected in 23.9% (424/1771) of the poultry and environmental samples. AIV detection rates in farms, transport vehicles, wholesale and retail LPMs were 4.5%, 11.1%, 30.3% and 51.2%, respectively. 5.2%, 8.3% and 12.8% of the poultry workers were seropositive in farms, wholesale and retail LPMs, respectively. The regression analysis showed that virus detection and transmission risk to human increased progressively along the poultry supply chain. ConclusionsStrengthening control measures at every level along the poultry supply chain, using a one health approach, is crucial to control AIV circulation.

Whole-Genome Sequence of an Avian Influenza A/H9N2 Virus Isolated from an Apparently Healthy Chicken at a Live-Poultry Market in Indonesia.

We isolated an avian influenza A/H9N2 virus from an apparently healthy chicken at a live-poultry market in January 2018. This is the first report of a whole-genome sequence of A/H9N2 virus in Indonesia. Phylogenetic analyses indicated that intrasubtype reassortment of genome segments is involved in the genesis of the A/H9N2 virus.

Identifying Risk Factors Of A(H7N9) Outbreak by Wavelet Analysis and Generalized Estimating Equation.

Five epidemic waves of A(H7N9) occurred between March 2013 and May 2017 in China. However, the potential risk factors associated with disease transmission remain unclear. To address the spatial–temporal distribution of the reported A(H7N9) human cases (hereafter referred to as “cases”), statistical description and geographic information systems were employed. Based on long-term observation data, we found that males predominated the majority of A(H7N9)-infected individuals and that most males were middle-aged or elderly. Further, wavelet analysis was used to detect the variation in time-frequency between A(H7N9) cases and meteorological factors. Moreover, we formulated a Poisson regression model to explore the relationship among A(H7N9) cases and meteorological factors, the number of live poultry markets (LPMs), population density and media coverage. The main results revealed that the impact factors of A(H7N9) prevalence are manifold, and the number of LPMs has a significantly positive effect on reported A(H7N9) cases, while the effect of weekly average temperature is significantly negative. This confirms that the interaction of multiple factors could result in a serious A(H7N9) outbreak. Therefore, public health departments adopting the corresponding management measures based on both the number of LPMs and the forecast of meteorological conditions are crucial for mitigating A(H7N9) prevalence.

Epidemiological characteristics of human infection with avian influenza A (H7N9) in Guilin

Objective To analyze the epidemiological characteristics of human infection with H7N9 avian influenza in Guilin in recent years and to provide on-site data and data support for scientific prevention and control of the epidemic of H7N9 avian influenza infection. Methods A descriptive epidemiological method was used to collect the data about human infection with H7N9 avian influenza form three aspects, which were human infection cases in 2017, environmental monitoring for H7N9 avian influenza virus and sentinel surveillance of influenza-like cases. The epidemiological characteristics of human infection with H7N9 avian influenza in Guilin in 2017 were analyzed. Chi-square test was used to compare the positive rates of H7N9 avian influenza virus in environmental specimens. Results A total of six cases of confirmed human H7N9 infection including three deaths were reported in Guilin city in 2017. These cases were from five counties and districts and all occurred in winter and spring. The patients were middle-aged and old men. Most of them were farmers and had a clear history of poultry exposure before the onset of infection. No human H7N9 infection was reported in close contacts or in influenza-like cases. Conclusions H7N9 avian influenza infection in Guilin was characterized by high sporadicity, high incidence in winter and spring, and predominantly middle-aged and elderly men. Avian exposure history was a high risk factor for human infection with H7N9 avian influenza virus. All of the studied cases were severe cases. No human-to-human transmission was reported. Farmers, having a history of poultry slaughter, and underlying diseases were potential risks causing death. Live poultry markets were the main sources of infection, hence closing market could reduce the detection rate of H7N9 avian influenza virus. Strengthen the management of live poultry market and poultry environmental monitoring, closing live poultry markets when viral detection was positive, and suspending live poultry trading were effective measures to control the epidemic of H7N9 avian influenza infection and prevent transmission. Key words: H7N9 avian influenza; Epidemiological characteristics; Prevention and control measures

Antibiotic resistance gene reservoir in live poultry markets

The heavy use of antibiotics in farm animals contributes to the enrichment and spread of antibiotic resistance genes (ARGs) in "one-health" settings. Numerous ARGs have been identified in livestock-associated environments but not in Chinese live poultry markets (LPMs). We collected 753 poultry fecal samples from LPMs of 18 provinces and municipalities in China and sequenced the metagenomes of 130 samples. Bioinformatic tools were used to construct the gene catalog and analyze the ARG content. PCR amplification and Sanger sequencing were used to survey the distribution of mcr-1 gene in all 753 fecal samples. We found that a low number of genes but a high percentage of gene functions were shared among the poultry, human and pig gut gene catalogs. The poultry gut possessed 539 ARGs which were classified into 235 types. Both the ARG number and abundance were significantly higher in poultry than that in either pigs or humans. Fourteen ARG types were found present in all 130 samples, and tetracycline resistance (TcR) genes were the most abundant ARGs in both animals and humans. Moreover, 59.63% LPM samples harbored the colistin resistance gene mcr-1, and other mcr gene variants were also found. We demonstrated that the Chinese LPMs is a repository for ARGs, posing a high risk for ARG dissemination from food animals to humans under such a trade system, which has not been addressed before.

Influenza A(H7N9) virus emerged and resulted in human infections in Chongqing, southwestern China since 2017

ObjectivesInfluenza A(H7N9) virus has emerged and resulted in human infections in Chongqing, southwestern China since 2017. This study aimed to describe the epidemiological characteristics of the first epidemic in this region. MethodsThe epidemiological data of patients were collected. Live poultry markets (LPMs), commercial poultry farms (CPFs) and backyard poultry farms (BPFs) were monitored, and poultry sources were registered. Samples derived from the patients, their close contacts, and the environments were tested for influenza A(H7N9) virus by real-time reverse transcriptase polymerase chain reaction. Genetic sequencing and phylogenetic analysis were also conducted. ResultsSince the confirmation of the first patient infected with influenza A(H7N9) virus on March 5, 2017, nine patients had been identified within four months in Chongqing. Their mean age was 45 years, 77.8% were male, 66.7% were urban residents and 55.6% were of poultry related occupation. All patients became infected after exposure to live chickens. The median time interval from initial detection of influenza A(H7N9) virus in Chongqing to the patients’ onset was 75 days. Since initial detection in February 2017, influenza A(H7N9) virus was detected in 21 (53.8%) counties within four months. The proportion of positive samples was 2.94% (337/11,451) from February 2017 to May 2018, and was higher (χ2=75.78, P<0.001) in LPMs (3.66%, 329/8979) than that in CPFs (0.41%, 5/1229) and BPFs (0.24%, 3/1243). The proportion of positive samples (34.4%, 22/64) at the premises to which the patients were exposed was significantly higher than that (5.7%, 257/4474) in premises with no patients. Phylogenetic analysis indicated that the viruses isolated in Chongqing belonged to the Yangtze River Delta lineage and resembled those circulated in Jiangsu and Anhui provinces between late 2016 and early 2017. ConclusionInfluenza A(H7N9) virus was newly introduced into Chongqing most likely between late 2016 and early 2017, which swept across half of Chongqing territory and resulted in human infections within months. The most impacted premises and population were LPMs and poultry related workers respectively in the epidemic.

Molecular characteristic analysis of neuraminidase genes of avian influenza virus H9N2 in environments in Weining, Guizhou Province during 2015-2017

Objective To understand the genetic variations of neuraminidase (NA) genes of avian influenza virus H9N2 in Weining, Guizhou Province, and to provide the scientific evidence for the prevention and control of avian influenza virus. Methods Ribonucleic acids (RNA) were extracted and NA genes were amplified and sequenced from 13 randomly selected H9N2 positive samples from the live poultry market (LPM) environments in north of Weining Yi and Hui and Miao autonomous county (Weining), Guizhou Province during 2015 to 2017. Then the homology, genetic evolution, and sites of stalk deletion areas, potential N-glycosylation, receptor binding regions and drug resistance of H9N2 subtype avian influenza viruses were analyzed by a series of bioinformation software. Results Homology analysis revealed that there were 93.0%-100.0% and 92.1%-100.0% similarity among 13 strains H9N2 avian influenza viruses in nucleotide and amino acid of the NA gene, respectively. All strains belonged to DK/HK/Y280/97 sub-lineage, but their genetic sources were complex and diverse. Thirteen strains had a stalk deletion of 3 amino acid residues TEI at positions 63-65 and 3 isolates had mutation QN to QK at positions 39-40. The potential N-glycosylation sites at amino acid residues 86, 146, 200, and 234 of the NA protein of all strains were highly conserved, while other N-glycosylation sites had quantity and site mutations. There were different mutation types at the three sialic acid binding site areas, especially at 399-404 area. All NA protease activity sites and key sites of the 13 strains had no mutations associated with resistance to the neuraminidase inhibitor drugs. Conclusions All 13 strains H9N2 viruses belongs to DK/HK/Y280/97 sub-lineage in Weining, Guizhou Province during 2015-2017, and their genetic sources are complex and diverse. The mutations on sites of stalk areas, potential N-glycosylation and sialic acid binding site areas are presented at different degrees. Hence, enhancing surveillance and controlling H9N2 avian influenza virus is necessary. Key words: Influenza A virus, H9N2 subtype; Neuraminidase gene; Molecular characteristic

Continuing evolution of highly pathogenic H5N1 viruses in Bangladeshi live poultry markets

ABSTRACT Since November 2008, we have conducted active avian influenza surveillance in Bangladesh. Clades 2.2.2, 2.3.4.2, and 2.3.2.1a of highly pathogenic avian influenza H5N1 viruses have all been identified in Bangladeshi live poultry markets (LPMs), although, since the end of 2014, H5N1 viruses have been exclusively from clade 2.3.2.1a. In June 2015, a new reassortant H5N1 virus (H5N1-R1) from clade 2.3.2.1a was identified, containing haemagglutinin, neuraminidase, and matrix genes of H5N1 viruses circulating in Bangladesh since 2011, plus five other genes of Eurasian-lineage low pathogenic avian influenza A (LPAI) viruses. Here we report the status of circulating avian influenza A viruses in Bangladeshi LPMs from March 2016 to January 2018. Until April 2017, H5N1 viruses exclusively belonged to H5N1-R1 clade 2.3.2.1a. However, in May 2017, we identified another reassortant H5N1 (H5N1-R2), also of clade 2.3.2.1a, wherein the PA gene segment of H5N1-R1 was replaced by that of another Eurasian-lineage LPAI virus related to A/duck/Bangladesh/30828/2016 (H3N8), detected in Bangladeshi LPM in September 2016. Currently, both reassortant H5N1-R1 and H5N1-R2 co-circulate in Bangladeshi LPMs. Furthermore, some LPAI viruses isolated from LPMs during 2016–2017 were closely related to those from ducks in free-range farms and wild birds in Tanguar haor, a wetland region of Bangladesh where ducks have frequent contact with migratory birds. These data support a hypothesis where Tanguar haor-like ecosystems provide a mechanism for movement of LPAI viruses to LPMs where reassortment with poultry viruses occurs adding to the diversity of viruses at this human-animal interface.

Detection of Infection Sources for Avian Influenza A(H7N9) in Live Poultry Transport Network During the Fifth Wave in China

Numerous studies have demonstrated that exposure to live poultry or live poultry markets is the significant risk factor for human infection with avian influenza A(H7N9). However, the specific live poultry markets that are major infection sources for A(H7N9) human cases have not been explored in detail. In this study, we extract data associated with poultry farms, live poultry markets and farmers' markets from Baidu Map using the JavaScript language and then construct the live poultry transport network. From this, we establish our A(H7N9) transmission model over the network based upon probabilistic discrete-time Markov chain. On the basis of the obtained network and model, we propose spatiotemporal backward detection and forward transmission algorithms to detect the most likely infection sources and to compute the first arrival times of the infection sources. Our simulations use these algorithms to identify the specific locations of the infection sources, the first arrival times of the infection sources and the most likely transmission map of the A(H7N9) virus along the live poultry transport network. The results reveal that, in addition to the hazards posed by the live poultry markets, backyard poultry also contributed to A(H7N9) human infections; this risk source was significant especially in the newly affected provinces, in the fifth wave of infection. In particular, by analyzing the temperature characteristics at a given location when the infection source arrived, we find that the risk of human infection with the influenza A(H7N9) virus was high under 9°C~19°C; moderate under 0°C~9°C or 19°C~25°C; and low for temperatures 25°C. Our results suggest that strengthening the supervision of the live poultry market system and immunizing poultry at both live poultry markets and the backyard poultry operations under the high risk temperature band of 9°C~19°C, will be able to significantly contribute to the control of avian influenza A(H7N9) in the future.

Knowledge, attitudes and practices towards avian influenza among live poultry market workers in Chongqing, China

BackgroundLive poultry market (LPM) workers are at high risk of infection with avian influenza virus due to frequent occupational exposure to poultry. This study aims to assess the knowledge, attitude and preventive practice regarding avian influenza among LPM workers in Chongqing, the largest municipality directly under the central government of China. Methods216 LPM workers were recruited by two-stage cluster sampling and interviewed face-to-face using a structured questionnaire. Hierarchical logistic regression analysis was performed to explore factors associated with preventive practices against avian influenza and views on government control measures. ResultsNearly half of respondents failed to recognize contact with sick birds or excrement as a risk of infection. Less than half the respondents perceived themselves to have a personal susceptibility to be infected or would like to enhance personal protection. Respondents did not pay sufficient attention to wearing preventive clothing such as gloves (43.1%), aprons/garments (33.3%) and face masks (26.9%) when handling live poultry. Few respondents were supportive to market control measures such as a ban on birds’ overnight storage (26.8%) or a regular rest day (32.4%). Being older, being more highly educated, having worked longer with poultry, having better knowledge, having more access to information, and perceiving more personal susceptibility to the disease were positively associated with preventive practices. Having higher personal income, longer engagement with poultry work, better knowledge, more awareness of personal protection were positively associated with agreement with government control measures. ConclusionsLPM workers in Chongqing showed low level of knowledge, weak perception of susceptibility to avian influenza and inadequate preventive behaviors. Health education campaigns need to better target the knowledge on transmission routes and potential outbreak threat of avian influenza. More attention should be paid to LPM workers who are younger, less educated, with shorter occupational years and lower personal income.

Avian Influenza A (H7N9) Model Based on Poultry Transport Network in China

In order to analyze the spread of avian influenza A (H7N9), we construct an avian influenza transmission model from poultry (including poultry farm, backyard poultry farm, live-poultry wholesale market, and wet market) to human according to poultry transport network. We obtain the threshold value for the prevalence of avian influenza A (H7N9) and also give the existence and number of the boundary equilibria and endemic equilibria in different conditions. We can see that poultry transport network plays an important role in controlling avian influenza A (H7N9). Finally, numerical simulations are presented to illustrate the effects of poultry in different places on avian influenza. In order to reduce human infections in China, our results suggest that closing the retail live-poultry market or preventing the poultry of backyard poultry farm into the live-poultry market is feasible in a suitable condition.

Surveillance of avian influenza virus in poultry environment in Henan Province, 2013-2017

Objective To monitor the environmental contamination with avian influenza virus (AIV) in Henan Province. Methods Environmental samples were collected every month from seven monitoring sites in Henan from 2013 to 2017. Real-time RT-PCR method was performed to detect the nucleic acid of influenza A (Flu A), H5, H7 and H9 viruses in poultry environmental samples. Results A total of 2 538 environmental samples were collected and 202 (7.96%) of them were positive for Flu A nucleic acid, including 16 positive for H5 (0.63%), eight positive for H7 (0.32%) and 161 positive for H9 (6.34%). The detection rate of Flu A increased dramatically from 2013 to 2017 except for a small fluctuation in 2015. However, H7 subtype AIV was detected only in 2015 and 2017. The highest detection rate of AIV was in February, followed by that in January. Among different environments, the highest detection rate of Flu A was in live poultry market, which was 13.69%, followed by that in poultry slaughtering plant (2.58%) and poultry farm (0.58%). The detection rates of Flu A in swab samples of poultry plucker and cutting board, stool specimens and poultry drinking water were 28.57%, 13.76%, 5.70% and 5.26%, respectively. Conclusion Contamination of H5/H7/H9 AIV did exist in poultry environment in Henan and was getting worse. Increasingly diversified sources and sale channels were the main causes of serious contamination of AIV. In order to effectively prevent and control human infection with AIV, live poultry in areas where human infection with AIV was confirmed should be blocked and banned to be sold to others areas. Key words: Avian influenza; H5/H7/H9 subtypes; Surveillance

Isolation and characterization of novel reassortant H6N1 avian influenza viruses from chickens in Eastern China

BackgroundThe H6N1 subtype of avian influenza viruses (AIVs) can infect people with an influenza-like illness; the H6N1 viruses possess the ability for zoonotic transmission from avians into mammals, and possibly pose a threat to human health.MethodsIn 2017, live poultry markets (LPMs) in Zhejiang Province were surveyed for AIVs. To better understand the genetic relationships between these strains from Eastern China and other AIVs, all gene segments of these strains were sequenced and compared with sequences available in GenBank. In this study, we analyzed the receptor-binding specificity, antigenic characteristics, and pathogenicity of these two H6N1 viruses.ResultsIn 2017, two H6N1 AIVs were isolated from chickens during surveillance for AIVs in LPMs in Eastern China. Phylogenetic analysis showed that these strains shared genetic characteristics from H6, H10, H1, and H4 AIVs found in ducks and wild birds in East Asia. These AIV strains were able to replicate in mice without prior adaptation.ConclusionsIn this study, we report the discovery of new strains of H6N1 viruses from chickens with novel gene reassortments. Our results suggest that these chickens play an important role generating novel reassortments in AIVs, and emphasize the need for continued surveillance of AIV strains circulating in poultry.

Avian Influenza A Virus Infection among Workers at Live Poultry Markets, China, 2013-2016.

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.

A case of human infection with highly pathogenic avian influenza A (H7N9) virus through poultry processing without protection measure

Objective: To investigate the infection pattern and etiological characteristics of a case of human infection with highly pathogenic avian influenza A (H7N9) virus and provide evidence for the prevention and control of human infection with highly pathogenic avian influenza virus. Methods: Epidemiological investigation was conducted to explore the case's exposure history, infection route and disease progression. Samples collected from the patient, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (RT-PCR). Virus isolation, genome sequencing and phylogenetic analysis were conducted for positive samples. Results: The case had no live poultry contact history, but had a history of pulled chicken processing without taking protection measure in an unventilated kitchen before the onset. Samples collected from the patient's lower respiratory tract, the remaining frozen chicken meat and the live poultry market were all influenza A (H7N9) virus positive. The isolated viruses from these positive samples were highly homogenous. An insertion which lead to the addition of multiple basic amino acid residues (PEVPKRKRTAR/GL) was found at the HA cleavage site, suggesting that this virus might be highly pathogenic. Conclusions: Live poultry processing without protection measure is an important infection mode of "poultry to human" transmission of avian influenza viruses. Due to the limitation of protection measures in live poultry markets in Guangzhou, it is necessary to promote the standardized large scale poultry farming, the complete restriction of live poultry sales and centralized poultry slaughtering as well as ice fresh sale.

Mitigation strategies to reduce the generation and transmission of airborne highly pathogenic avian influenza virus particles during processing of infected poultry.

Airborne transmission of H5N1 highly pathogenic avian influenza (HPAI) viruses has occurred among poultry and from poultry to humans during home or live-poultry market slaughter of infected poultry, and such transmission has been experimentally reproduced. In this study, we investigated simple, practical changes in the processing of H5N1 virus-infected chickens to reduce infectious airborne particles and their transmission. Our findings suggest that containing the birds during the killing and bleeding first step by using a disposable plastic bag, a commonly available cooking pot widely used in Egypt (halla), or a bucket significantly reduces generation of infectious airborne particles and transmission to ferrets. Similarly, lack of infectious airborne particles was observed when processing vaccinated chickens that had been challenged with HPAI virus. Moreover, the use of a mechanical defeatherer significantly increased total number of particles in the air compared to manual defeathering. This study confirms that simple changes in poultry processing can efficiently mitigate generation of infectious airborne particles and their transmission to humans.

Molecular characteristics and tracing of hemagglutinin of the first highly pathogenic avian influenza A (H7N9) virus mutant strain infection case in Guizhou Province

Objective To investigate the molecular characteristics and tracing of the hemagglutinin (HA) gene, and to analyze the risk of human infection with influenza virus A (H7N9) in Guizhou Province, so that to provide evidence for the prevention and control of highly pathogenic avian influenza A (H7N9). Methods Nucleic acids of 5 strains of H7N9 including 1 sample of the patient′s nasopharyngeal swab and 4 samples of the live poultry market (LPM) environment were extracted and HA genes were amplified and sequenced. Then the homology, genetic evolution and the pivotal sites related to receptor binding regions, pathogenicity and potential glycosylation of the avian influenza A (H7N9) viruses were analyzed by a series of bioinformatics softwares. Results Homology analysis revealed that the homologies of nucleotide and amino-acid of the HA gene of H7N9 strains from the patient and LPM in Weining County, Guizhou Province were 99.8% and 99.6%, respectively, while those of 4 strains from LPM were both 100%. The homologies of nucleotide and amino-acid of the HA gene of H7N9 strains were the highest with the strain of A/Guangxi/5/2017 isolated from a Guangxi infected patient (99.7%-99.9% and 99.4%-99.8%, respectively), while those with the strain isolated from LPMs environment at the end of 2016 (A/Environment/Guangdong/C16283222/2016) were 99.0%-99.2% and 98.9%-99.2%, respectively. However, the homologies of nucleotide and amino-acid of the HA gene of H7N9 strains with A/Shanghai/2/2013 recommended by world health organization and the candidate vaccine strain A/Anhui/1/2013 were 96.8%-97.0% and 95.8%-96.2%, respectively. Phylogenetic analysis showed that the 5 strains had the nearest genetic distance to the strain A/Guangxi/5/2017. All the 5 strains cleavage site sequences of HA protein showed mutation of PEVPKRKRTAR↓GLF, and they were highly pathogenic avian influenza viruses mutant strains, which all had mutation of G186V at the receptor binding sites of HA gene, while no Q226L mutation was found. All 5 strains had new mutation of A363S, and new mutations of R56K and I297V were only found in the strain isolated from the patient. Among the five potential glycosylation motifs in the HA, only 421NWT and 493NNT had variation of the position post shift. Conclusions All the 5 H7N9 strains isolated in Weining County, Guizhou Province are highly pathogenic avian influenza mutative viruses. The current candidate vaccine may not provide a very good protection. The mutations of cleavage site of HA protein, G186V as well as other new mutation sites of HA may enhance the susceptibility and pathogenicity to human beings. Key words: High pathogenic avian influenza A(H7N9)virus; Hemagglutinin gene; Molecular characteristic; Tracing