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

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 155759-155778 ◽  
Author(s):  
Xin Pei ◽  
Zhen Jin ◽  
Wenyi Zhang ◽  
Yong Wang
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Transport Network ◽  
Live Poultry

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 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.

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 Predicting the risk of avian influenza A H7N9 infection in live-poultry markets across Asia

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Marius Gilbert ◽  
Nick Golding ◽  
Hang Zhou ◽  
G. R. William Wint ◽  
Timothy P. Robinson ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Live Poultry ◽  
H7n9 Infection ◽  
Live Poultry Markets

scholarly journals Clinical and epidemiological characteristics of a young child infected with avian influenza A (H9N2) virus in China

2018 ◽  
Vol 46 (8) ◽  
pp. 3462-3467 ◽  
Author(s):  
Ruchun Liu ◽  
Bin Zhao ◽  
Yelan Li ◽  
Xixing Zhang ◽  
Shuilian Chen ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Large City ◽  
H9n2 Virus ◽  
Influenza Surveillance ◽  
Highly Pathogenic ◽  
Live Poultry ◽  
Epidemiological Characteristics ◽  
Central South ◽  
Live Poultry Markets

Three cases of the avian influenza A (H9N2) virus have been documented in Changsha, which is a large city that has nine districts and a population of 7.04 million in central South China. Among these patients, one was a girl and two were boys. The ages of the patients were 9 months, 2 years, and 15 years. Two cases of H9N2 were detected in September, 2015 and one was detected in 2017. Two patients were children who had not reached the age for kindergarten and one was a student. These three cases were all mild and were detected in a sentinel hospital of the Chinese Influenza Surveillance System. We describe the clinical and epidemiological features of the youngest patient with H9N2 in 2017 and the surveillance results of the H9N2 virus in live poultry markets in Changsha. From January 2014 to December 2017, 4212 samples were collected in live poultry markets in Changsha, among which 25.81% (1087/4212) were H9N2-positive. Public health concerns should be addressed for emerging H9N2 virus infection, and more strategies should be performed before this virus mutates to be more transmissible and highly pathogenic.

scholarly journals Interventions in live poultry markets for the control of avian influenza: A systematic review

One Health ◽  
2016 ◽  
Vol 2 ◽  
pp. 55-64 ◽  
Author(s):  
Vittoria Offeddu ◽  
Benjamin J. Cowling ◽  
J.S. Malik Peiris
Keyword(s):  
Systematic Review ◽  
Avian Influenza ◽  
Influenza A ◽  
Live Poultry ◽  
Live Poultry Markets

scholarly journals Emergence of human avian influenza A(H7N9) virus infections in Wenshan City in Southwest China, 2017

2019 ◽  
Author(s):  
Li Jiang ◽  
Xiaonan Zhao ◽  
Wen Xu ◽  
Xuehua Zhou ◽  
Chunrui Luo ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Avian Influenza ◽  
Influenza A ◽  
Human Infection ◽  
Viral Gene ◽  
H7n9 Virus ◽  
Genetic Sequencing ◽  
Live Poultry ◽  
Virus Spreading ◽  
Live Poultry Markets

Abstract Background: The emergence of human infection with avian influenza A(H7N9) virus was reported in Wenshan City, southwestern China in 2017. The study describes the epidemiological and virological features of the outbreak and discusses the origin of the infection. Methods: Poultry exposure and timelines of key events for each patient were collected. Samples derived from the patients, their close contacts, and environments were tested for influenza A(H7N9) virus by real-time reverse transcription polymerase chain reaction. Genetic sequencing and phylogenetic analysis were also conducted. Results: Five patients were reported in the outbreak. An epidemiological investigation showed that all patients had been exposed at live poultry markets. Virus isolates from these patients had low pathogenicity in avian species. Both epidemiological investigations of chicken sources and phylogenetic analysis of viral gene sequences indicated that the source of infection was from Guangxi Province. Conclusions: The transmission route spanned a long geographical region, with virus spreading from east to west. Chickens were an important carrier in the H7N9 virus spreading from Guangxi to Wenshan. Hygienic management of live poultry markets and virological screening of chickens transported across regions should be reinforced to limit the spread of H7N9 virus.

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