scholarly journals Identifying Key Transmission Route of Avian Influenza A(H9N2) in Live Poultry Markets

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Eric Lau ◽  
Shengqiu Zhang ◽  
Connie Leung ◽  
Benjamin J. Cowling ◽  
Joseph T. Wu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Avian Influenza ◽  
Water Samples ◽  
Influenza A ◽  
Influenza Viruses ◽  
Transmission Route ◽  
Fecal Samples ◽  
Oral Transmission ◽  
Live Poultry ◽  
Water Transmission

ObjectiveThis study assessed the transmission of low pathogenic avianinfluenza in live poultry market setting, using paired fecal anddrinking water samples from a longitudinal surveillance program.The relative contribution of transmission via direct fecal-oral routeversus drinking water will be determined.IntroductionLive poultry markets (LPMs) continue to operate in many Asiancountries. Low pathogenic avian influenza (LPAI) viruses areoften endemic in the poultry, and LPM presents the opportunity forhuman-poultry interactions and potential human infections with avianinfluenza viruses.As a series of interventions to control avian influenza transmissionin Hong Kong LPMs, local health authority implemented marketrest days once every month since mid-2001, and an additional restday every month since 2003, during which all unsold poultry wereslaughtered and the stalls cleaned and disinfected. Rest days werefound to effectively reduce avian influenza A(H9N2) isolation rateto baseline level for a few days following the rest days. However,H9N2 isolation rate was still observed to be increasing between therest days, indicating the existence of efficient transmission in spite ofrapid turnover of poultry.In LPMs, poultry are usually stored in cages where drinkingwater is shared among poultry. This is analogous to environmentalcontamination in the wild, but transmissibility may even be higherdue to the dense environment. The use of drinking water for avianinfluenza surveillance in LPM setting was suggested to be moresensitive than fecal samples (1). However, the relative contributionof direct fecal-oral versus water transmission routes in the LPMsetting was not yet understood. This study aimed to determine theirrole, which will have implications in the control of avian influenzatransmission.MethodsWe analyzed 7,321 paired fecal and drinking water samplesfrom a longitudinal surveillance programme during the period with2 monthly rest days in the LPMs. Samples were collected fromchicken cages and subsequently cultured. Positive isolates weresubtyped by hemagglutination-inhibition tests and neuraminidaseinhibition test. Data were aggregated by sampling occasion and daysafter the rest days.A compartmental transmission model which incorporated turnoverand overnight stay of poultry, virus contamination and decay indrinking water was fitted to the data (Figure 1). A 12-hour tradingday was assumed. Based on the parameterized model, we simulatedthe scenario that water transmission was prohibited to assess the roleof transmission via drinking water.ResultsH9N2 isolation rates ranged from 0-25% for fecal samples and0-56% for drinking water samples. A clear increasing trend can beseen over days after the rest days (Figure 2). The estimated parameterfor water transmission is higher than the parameter for direct fecal-oraltransmission. Simulation results show that transmission via drinkingwater plays a major role in the amplification of LPAI in the LPMsetting (Figure 2).ConclusionsOur study showed that drinking water has a major role in thetransmission and amplification of LPAI H9N2 in LPMs, comparingto direct fecal-oral transmission route. Given the relatively lowprevalence of H9N2 in chicken, direct transmission is governed bychance events, while chickens are consistently exposed to viruses indrinking water if contaminated. Drinking water could be targeted forintervention to control LPAI transmission in LPM. The use of drinkingfountain or frequent disinfection of drinking water may be considered.Avian influenza viruses (e.g. H5N1) may differ in their pattern ofvirus shedding via oral versus fecal routes and thus extrapolation ofthese results to other viruses needs to be done with caution. However,H7N9 viruses are similar to H9N2 viruses by being shed primarilyvia the respiratory / oral route (2) and it is reasonable to assume thatthese conclusions would apply to H7N9 virus which is of major publichealth concern. However, our model could not differentiate the effectof indirect fecal-oral transmission through contamination of drinkingwater by droppings versus contamination through drinking.

scholarly journals The Impact of the Closure of the Live Poultry Market due to COVID-19 on the Avian Influenza Virus in Nanchang, Jiangxi Province, China

2021 ◽  
Author(s):  
Jin Guo ◽  
Wentao Song ◽  
Xiansheng Ni ◽  
Kun Zhou ◽  
Jingwen Wu ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Jiangxi Province ◽  
Detection Rates ◽  
Before And After ◽  
Avian Influenza A Virus ◽  
Positive Rate ◽  
Live Poultry ◽  
The Impact

This article aims to understand the changes in the detection rates of H5, H7, and H9 subtypes of avian influenza viruses (AIVs) in the live poultry markets (LPMs) in Nanchang City, Jiangxi Province, before and after the outbreak of the COVID-19. From 2019 to 2020, we monitored the LPM and collected specimens, using real-time reverse transcription polymerase chain reaction technology to detect the nucleic acid of type A AIV in the samples. The H5, H7, and H9 subtypes of influenza viruses were further classified for positive results. We analyzed 1,959 samples before and after the outbreak and found that the positive rates of avian influenza A virus (39.69%) and H9 subtype (30.66%) after the outbreak were significantly higher than before the outbreak (26.84% and 20.90%, respectively; P < 0.001). In various LPMs, the positive rate of H9 subtypes has increased significantly (P ≤ 0.001). Positive rates of the H9 subtype in duck, fecal, daub, and sewage samples, but not chicken samples, have increased to varying degrees. This study shows that additional measures are needed to strengthen the control of AIVs now that LPMs have reopened after the relaxing of COVID-19–related restrictions.

scholarly journals Isolation of H5N6, H7N9 and H9N2 avian influenza A viruses from air sampled at live poultry markets in China, 2014 and 2015

2016 ◽  
Vol 21 (35) ◽  
Author(s):  
Jie Zhou ◽  
Jie Wu ◽  
Xianqiao Zeng ◽  
Guofeng Huang ◽  
Lirong Zou ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Avian Influenza Viruses ◽  
Guangzhou City ◽  
Modes Of Transmission ◽  
Zoonotic Infections ◽  
Live Poultry ◽  
Live Poultry Markets

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 μm 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.

scholarly journals Development of an immunochromatographic strip for rapid detection of H7 subtype avian influenza viruses

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ge Li ◽  
Xun Wang ◽  
Qingmei Li ◽  
Jifei Yang ◽  
Xiao Liu ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Point Of Care ◽  
Influenza Viruses ◽  
Control Line ◽  
Avian Influenza Viruses ◽  
Igg Antibody ◽  
Immunochromatographic Strip ◽  
Live Poultry ◽  
Pathogenic Viruses ◽  
H7 Subtype

Abstract Background H7N9 avian influenza virus (AIV) including highly and low pathogenic viruses have been detected in China since 2013. H7N9 AIV has a high mortality rate after infection in humans, and most human cases have close contacted with poultry in the live poultry market. Therefore, it is necessary to develop a rapid point-of-care testing (POCT) technique for H7N9 AIV detection. Methods The H7N9 AIV was inactivated and purified, and was used as the antigen to immunize BALB/c. Twelve H7-HA specific monoclonal antibodies (McAbs) were produced through the hybridoma technique. The McAb 10A8 was conjugated with colloid gold as detecting antibody; McAb 9B6 was dispensed on the nitrocellulose membran as the capture test line and the Goat-anti mouse IgG antibody was dispensed as control line respectively. The immunochromatographic strip was prepared. Results The analysis of ELISA and virus neutralization test showed that the obtained McAbs specifically recognized H7 HA. Based on the prepared strip, the detection of H7 AIV was achieved within 10 min. No cross-reaction occurred between H7 AIVs and other tested viruses. The detection limit of the strip for H7 was 2.4 log10EID50/0.1 mL for chicken swab samples. Conclusion The McAbs were specific for H7 and the immunochromatographic strip developed in this study was convenient, rapid and reliable for the detection of H7 AIV. The strip could provide an effective method for the rapid and early detection of H7 AIV.

scholarly journals Ecology of H3 avian influenza viruses in Korea and assessment of their pathogenic potentials

2008 ◽  
Vol 89 (4) ◽  
pp. 949-957 ◽  
Author(s):  
Min-Suk Song ◽  
Taek-Kyu Oh ◽  
Ho Jin Moon ◽  
Dai-Woon Yoo ◽  
Eun Ho Lee ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Wild Bird ◽  
Migratory Birds ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Avian Influenza Viruses ◽  
Backyard Poultry ◽  
Live Poultry ◽  
Live Poultry Markets

To determine the genetic origins of novel H3 avian influenza viruses of chickens and ducks in Korea, genetic characterization of H3 avian influenza viruses isolated from live poultry markets and migratory aquatic birds in South Korea during 2004–2006 was conducted. Phylogenetic analysis revealed that at least four novel genotypes of H3N2 and two genotypes of H3N6 avian influenza viruses were co-circulating in backyard poultry of Korea. The viruses were reassortants between H9N2 viruses of Korean chickens and unknown influenza viruses of migratory birds. Genetic comparison of H3 viruses from live bird markets with those from wild bird isolates revealed that certain gene segments of wild bird isolates are related closely to those of Korean group H9N2 viruses isolated from live poultry markets in 2003. Furthermore, animal-challenge studies demonstrated that the pathogenicity of certain avian H3 influenza viruses was altered due to reassortment, leading to H3 avian influenza viruses in Korea that can potentially expand their host range to include mammals. These studies emphasize the continuing need to monitor backyard poultry at live poultry markets to better understand interspecies transmission and the emergence of novel influenza viruses that have the potential to infect humans.

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

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Juping Zhang ◽  
Wenjun Jing ◽  
Wenyi Zhang ◽  
Zhen Jin
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Suitable Condition ◽  
Threshold Value ◽  
Transport Network ◽  
Transmission Model ◽  
Poultry Farm ◽  
Wholesale Market ◽  
Backyard Poultry ◽  
Live Poultry

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.

scholarly journals Evolution and Adaptation of the Avian H7N9 Virus into the Human Host

2020 ◽  
Vol 8 (5) ◽  
pp. 778
Author(s):  
Andrew T. Bisset ◽  
Gerard F. Hoyne
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Influenza A ◽  
Amino Acid Sequences ◽  
Influenza Viruses ◽  
Amino Acid Substitutions ◽  
Upper Respiratory Tract ◽  
Viral Polymerase ◽  
Evolutionary Changes ◽  
Avian Origin

Influenza viruses arise from animal reservoirs, and have the potential to cause pandemics. In 2013, low pathogenic novel avian influenza A(H7N9) viruses emerged in China, resulting from the reassortment of avian-origin viruses. Following evolutionary changes, highly pathogenic strains of avian influenza A(H7N9) viruses emerged in late 2016. Changes in pathogenicity and virulence of H7N9 viruses have been linked to potential mutations in the viral glycoproteins hemagglutinin (HA) and neuraminidase (NA), as well as the viral polymerase basic protein 2 (PB2). Recognizing that effective viral transmission of the influenza A virus (IAV) between humans requires efficient attachment to the upper respiratory tract and replication through the viral polymerase complex, experimental evidence demonstrates the potential H7N9 has for increased binding affinity and replication, following specific amino acid substitutions in HA and PB2. Additionally, the deletion of extended amino acid sequences in the NA stalk length was shown to produce a significant increase in pathogenicity in mice. Research shows that significant changes in transmissibility, pathogenicity and virulence are possible after one or a few amino acid substitutions. This review aims to summarise key findings from that research. To date, all strains of H7N9 viruses remain restricted to avian reservoirs, with no evidence of sustained human-to-human transmission, although mutations in specific viral proteins reveal the efficacy with which these viruses could evolve into a highly virulent and infectious, human-to-human transmitted virus.

Equine and canine influenza: a review of current events

2010 ◽  
Vol 11 (1) ◽  
pp. 43-51 ◽  
Author(s):  
E. Paul J. Gibbs ◽  
Tara C. Anderson
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Influenza A ◽  
One Health ◽  
Control Strategies ◽  
Close Association ◽  
Companion Animals ◽  
Emerging Diseases ◽  
Influenza Viruses ◽  
Canine Influenza

AbstractIn the past decade, the pandemics of highly pathogenic avian influenza H5N1 and the novel H1N1 influenza have both illustrated the potential of influenza viruses to rapidly emerge and spread widely in animals and people. Since both of these viruses are zoonotic, these pandemics have been the driving force behind a renewed commitment by the medical and veterinary professions to practice One World, One Health for the control of infectious diseases. The discovery in 2004 that an equine origin H3N8 influenza virus was the cause of an extensive epidemic of respiratory disease in dogs in the USA came as a surprise; at that time dogs were thought to be refractory to infection with influenza viruses. In 2007, a second emerging canine influenza was confirmed in Korea, but this time the causal virus was an H3N2 avian influenza virus. This review focuses on recent events associated with equine and canine influenza viruses. While these viruses do not appear to be zoonotic, the close association between humans and dogs, and to a lesser extent horses, demands that we develop better surveillance and control strategies for emerging diseases in companion animals within the context of One World, One Health.

scholarly journals Live Poultry Market Closure and Avian Influenza A (H7N9) infection in cities of China, 2013-2017: An ecological study

2020 ◽  
Author(s):  
Ying Chen ◽  
Jian Cheng ◽  
Zhiwei Xu ◽  
Wenbiao Hu ◽  
Jiahai Lu
Keyword(s):  
Avian Influenza ◽  
Risk Reduction ◽  
Influenza A ◽  
Reduction Rate ◽  
Dominant Factor ◽  
Effective Measure ◽  
Partial Closure ◽  
Live Poultry ◽  
H7n9 Infection ◽  
The Impact

Abstract Background Previous studies have proven that the closure of live poultry markets (LPMs) was an effective intervention to reduce human risk of avian influenza A (H7N9) infection, but evidence is limited on the impact of scale and duration of LPMs closure on the transmission of H7N9. Method Five cities (i.e., Shanghai, Suzhou, Shenzhen, Guangzhou and Hangzhou) with the largest number of H7N9 cases in mainland China from 2013-2017 were selected in this study. Data on laboratory-confirmed H7N9 human cases in those five cities were obtained from the Chinese National Influenza Centre. The detailed information of LPMs closure (i.e., area and duration) was obtained from the Ministry of Agriculture. We used a generalized linear model with a Poisson link to estimate the effect of LPMs closure, reported as relative risk reduction (RRR). We used classification and regression trees (CARTs) to select and quantify the dominant factor of H7N9 infection. Results All five cities implemented the LPMs closure, and the risk of H7N9 infection decreased significantly after LPMs closure with RRR ranging from 0.80-0.93. Respectively, a long-term LPMs closure for 10-13 weeks elicited a sustained and highly significant risk reduction of H7N9 infection (RRR = 0.98). Short-time LPMs closure with 2 weeks in every epidemic did not reduce the risk of H7N9 infection (p>0.05). Partially closed LPMs in some suburbs contributed only 35% for reduction rate (RRR=0.35). Shenzhen implemented partial closure for first 3 epidemics (p>0.05) and all closure in the latest 2 epidemic waves (RRR=0.64). Conclusion Our findings suggest that LPMs all closure in whole city can be a highly effective measure comparing with partial closure (i.e. only urban closure, suburb and country remain open). Extend the duration of closure and consider permanently closing the LPMs will help improve the control effect. The effect of LPMs closure is greater than that of meteorology on H7N9 transmission.

scholarly journals Extensive surveillance for avian influenza A(H5N6) virus in Southern China

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Xin Wang ◽  
Shisong Fang
Keyword(s):  
Avian Influenza ◽  
Antibody Titer ◽  
Influenza A ◽  
Southern China ◽  
Type A ◽  
Human Infection ◽  
Rt Pcr ◽  
Influenza Type ◽  
Live Poultry ◽  
Poultry Workers

ObjectiveTo determine avian influenza A(H5N6) virus infection in humanand environment using extensive surveillances. To evaluate theprevalence of H5N6 infection among high risk population.IntroductionSince the emergence of avian influenza A(H7N9) virus in 2013,extensive surveillances have been established to monitor the humaninfection and environmental contamination with avian influenza virusin southern China. At the end of 2015, human infection with influenzaA(H5N6) virus was identified in Shenzhen for the first time throughthese surveillances. These surveillances include severe pneumoniascreening, influenza like illness (ILI) surveillance, follow-up onclose contact of the confirmed case, serological survey among poultryworkers, environment surveillance in poultry market.MethodsSevere pneumonia screening was carried out in all hospitals ofShenzhen. When a patient with severe pneumonia is suspected forinfection with avian influenza virus, after consultation with at leasttwo senior respiratory physicians from the designated expert paneland gaining their approval, the patient will be reported to local CDC,nasal and pharyngeal swabs will be collected and sent for detectionof H5N6 virus by RT-PCR.ILI surveillance was conducted in 11 sentinel hospitals, 5-20 ILIcases were sampled for detection of seasonal influenza virus by RT-PCR test every week for one sentinel. If swab sample is tested positivefor influenza type A and negative for subtypes of seasonal A(H3N2)and A(H1N1), it will be detected further for influenza A(H5N6) virus.Follow-up on close contacts was immediately carried out whenhuman case of infection with H5N6 was identified. All of closecontacts were requested to report any signs and symptoms of acuterespiratory illness for 10 days, nasal and pharyngeal swabs werecollected and tested for influenza A(H5N6) virus by RT-PCR test.In the meantime, environmental samples were collected in the marketwhich was epidemiologically associated with patient and tested forH5N6 virus by RT-PCR test.Serological survey among poultry workers was conducted in tendistricts of Shenzhen. Poultry workers were recruited in poultrymarkets and screened for any signs and symptoms of acute respiratoryillness, blood samples were collected to detect haemagglutination-inhibition (HI) antibody for influenza A(H5N6) virus.Environment surveillance was conducted twice a month in tendistricts of Shenzhen. For each district, 10 swab samples werecollected at a time. All environmental samples were tested forinfluenza A(H5N6) virus by RT-PCR test.ResultsFrom Nov 1, 2015 to May 31, 2016, 50 patients with severepneumonia were reported and detected for H5N6 virus, three patientswere confirmed to be infected with H5N6 virus. Case 1 was a 26 yearsold woman and identified on Dec 29, 2015. She purchased a duck ata live poultry stall of nearby market, cooked and ate the duck 4 daysbefore symptom onset. After admission to hospital on Dec 27, hercondition deteriorated rapidly, on Dec 30 she died. The case 2 was a25 years old man and confirmed on Jan 7, 2016. He visited a marketeveryday and had no close contact with poultry, except for passingby live poultry stalls. He recovered and was discharged from hospitalon Jan 22. The case 3 was is a 31 years old woman and reported onJan 16, 2016, she had no contact with live poultry and died on Feb 8.For 60 close contacts of three cases, none of them reported signsor symptoms of acute respiratory illness, all of nasal and pharyngealswabs were tested negative for influenza A(H5N6) virus by RT-PCRtest. Of 146 environmental swabs collected in the case’s living placesand relevant poultry markets, 38 were tested positive for influenzaA(H5N6) virus by RT-PCR test.From Nov 1, 2015 to May 31, 2016, 2812 ILI cases were sampledand tested for influenza type A and subtypes of seasonal influenza.Those samples tested positive for influenza type A could be furthersubtyped to seasonal A(H3N2) or A(H1N1), therefore no sample fromILI case was tested for influenza A(H5N6) virus.Serological surveys among poultry workers were conductedtwice, for the first survey 186 poultry workers were recruited in Oct2015, for the second survey 195 poultry workers were recruited inJan 2016. Blood sample were collected and tested for HI antibodyof influenza A(H5N6) virus. 2 individuals had H5N6 HI antibodytiter of 1:40, 5 individuals had H5N6 HI antibody titer of 1:20, rest ofthem had H5N6 HI antibody titer of <1:20. According to the WHOguideline, HI antibody titer of≥1:160 against avian influenza viruswere considered positive.From Nov 1, 2015 to May 31, 2016, of 1234 environmental swabscollected in poultry markets, 339 (27.5%)were tested positive forinfluenza A(H5N6) virus by RT-PCR test. Each of the ten districtshad poultry markets which was contaminated by influenza A(H5N6)virus.ConclusionsIn 2015-2016 winter, three cases of infection with influenzaA(H5N6) virus were identified in Shenzhen, all of them were youngindividuals with average age of 27.3 years and developed severepneumonia soon after illness onset, two cases died. For acute andsevere disease, early detection and treatment is the key measure forpatient’s prognosis.H5N6 virus was identified in poultry market and other placeswhere patient appeared, implying poultry market probably was thesource of infection. Despite the high contamination rate of H5N6virus in poultry market, we found that the infection with H5N6 virusamong poultry workers was not prevalent, with infection rate being0/381. Human infection with H5N6 virus seemed to be a sporadicoccurrence, poultry-human transmission of H5N6 virus might not bevery effective.

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