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Objective The aim is to analyze the spatial epidemiological characteristics for human infection with avian influenza H7N9 in Fujian Province, so as to provide scientific evidence for developing and adjusting related control strategies. Methods The epidemiological data of human infection with H7N9 avian influenza in Fujian Province, from 2013 to 2017 was analyzed by SAS 9.2, ArcGIS 10.3 and SaTScan 9.4 software.Results There were a total of 108 cases and 28 deaths reported in Fujian Province, up to December 31, 2017. The case fatality rate was 25.93%.96.30% of cases were sporadic. There were more incidences in winters and springs, more incidences in rural areas. The global spatial autocorrelation and high/low clustering analysis indicated that clusters at the county level were in the shore areas (Z=3.74, P<0.001; Z=5.26, P<0.001). The cities of Changle, Fuqing, Jinjiang and Siming were the high-high clustered areas and local hot-points. There were two clusters, from December 2014 to March 2015, the most likely cluster regions was centered around Zhangpu County with a radius of 63.04 km (RR=4.72, LLR=11.41, P<0.001). The secondary cluster regions was centered around Fuqing City with a radius of 81.98 km (RR=4.07, LLR=7.96, P=0.037). Conclusions Human infection with avian influenza H7N9 in Fujian Province is spatially and temporally clustered. The measures of prevention and control should be focused on high incidence seasons and key regions, and the surveillance of etiology should be strengthened.
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Objective To understand the epidemiological characteristics of human infection with avian influenza A (H7N9) virus in China,and provide evidence for the prevention and control of human infection with H7N9 virus.Methods The published incidence data of human infection with H7N9 virus in China from March 2013 to April 2017 were collected.Excel 2007 software was used to perform the analysis.The characteristics of distribution of the disease,exposure history,cluster of the disease were described.Results By the end of April 2017,a total of 1 416 cases of human infection with H7N9 virus were confirmed in China,including 559 deaths,the case fatality rate was 39.5％.In 2016,the case number was lowest (127 cases),with the highest fatality rate (57.5％).The first three provinces with high case numbers were Zhejiang,Guangdong and Jiangsu.The median age of the cases was 55 years and the male to female ratio was 2.3 ∶ 1.Up to 66％ of cases had clear live poultry exposure history before illness onset,31％ of cases had unknown exposure history and only 3％ of the cases had no live poultry exposure history.There were 35 household clusters (5 in 2013,9 in 2014,6 in 2015,5 in 2016,10 in 2017),which involved 72 cases,accounting for 5％ of the total cases.Conclusions The epidemic of human infection with H7N9 virus in China during 2013-2017 had obvious seasonality and spatial distribution.There was limited family clustering.Infection cases were mostly related to poultry contact.
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Objective To understand the epidemiological characteristics of human infection with avian influenza A (H7N9) virus in China,and provide evidence for the prevention and control of human infection with H7N9 virus.Methods The published incidence data of human infection with H7N9 virus in China from March 2013 to April 2017 were collected.Excel 2007 software was used to perform the analysis.The characteristics of distribution of the disease,exposure history,cluster of the disease were described.Results By the end of April 2017,a total of 1 416 cases of human infection with H7N9 virus were confirmed in China,including 559 deaths,the case fatality rate was 39.5％.In 2016,the case number was lowest (127 cases),with the highest fatality rate (57.5％).The first three provinces with high case numbers were Zhejiang,Guangdong and Jiangsu.The median age of the cases was 55 years and the male to female ratio was 2.3 ∶ 1.Up to 66％ of cases had clear live poultry exposure history before illness onset,31％ of cases had unknown exposure history and only 3％ of the cases had no live poultry exposure history.There were 35 household clusters (5 in 2013,9 in 2014,6 in 2015,5 in 2016,10 in 2017),which involved 72 cases,accounting for 5％ of the total cases.Conclusions The epidemic of human infection with H7N9 virus in China during 2013-2017 had obvious seasonality and spatial distribution.There was limited family clustering.Infection cases were mostly related to poultry contact.
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To analyze the epidemiological characteristics of human infection with avian influenza A(H7N9) virus from 2013 to 2016 in Xiaoshan,China,we collected the epidemiological data of human A(H7N9) cases as well as the results of environmental monitoring and analyzed it by case study,descriptive epidemiological method,and statistical analysis.Results showed that a total of 22 cases were confirmed,including 12 deaths.All the cases occurred in winter and spring,and most of them had been exposed to live poultry,and with the underlying condition of chronic diseases.Chi-square test showed that the ratio of cases with chronic diseases in death group was higher (P=0.01).The environmental monitoring result showed there were distinctive seasonal differences of positive rate with peaks in winter and spring and nadirs in autumn and summer.Positive rates for the samples from external environmental monitoring were consistent with the distribution of the case onset.Due to rise of environmental monitoring positive rate,we should be alert to the occurrence of new cases,especially in rural areas where live poultry fairs still exist and among people with occupational exposure.We should further improve ability to prevent and control this disease.
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We analyzed genetic evolution characteristics of avian influenza A (H7N9) virus isolated in Zhaoqing,China,2014-2016.Nucleic acid were extracted and sequenced from 17 samples of H7N9 positive cases in Zhaoqing.Genetic characteristics of homology and important amino acid sites were analyzed by using BioEdit5.0 and MEGA6.0.The evolutionary trees were constructed by Neighbor-Joining and the referenced sequences were downloaded from GenBank,Eight nucleic acid fragments from 7 strains of H7N9 viruses were successfully generated.The highest homology was found in HA gene with A/chicken/Dongguan/695/2014(H7N9),and NA gene with A/chicken/Dongguan/1075/2014(H7N9).The internal genes were high homology with avian H7N9 and H9N2 virus from Dongguan and Shenzhen in Guangdong,China.The HA and NA genes were directly evolved in the Pearl River Delta evolution branch with the H7N9 sequences from the cities of Dongguan,Guangzhou and Shenzhen,while the sequences from the provinces of Anhui,Zhejiang,and Jiangsu were in the Yangtze River Delta evolution branch.There were 2 alkaline amino acids in cleavage site of HA,2 mutations (G186V and Q226L) in the crucial sites related with the receptor of HA protein,1 mutation (E627K) in PB2 protein,and 1 drug resistance mutation (S31N) in M2 protein.And no evidence of neuraminidase resistance in NA protein was found.In conclusion,the H7N9 virus for human infection in Zhaoqing may originate from avian H7N9 and H9N2 viruses,which circulated in the Pearl River Delta region of Guangdong from 2013 to 2014.The mutations of G186V,Q226L and E627 K might be related with high susceptibility to human beings.
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Objective To analyze the clinical and epidemiological characteristics of human avian influenza A (H7N9 ) epidemic in Jiaxing City,and to provide scientific basis for the control and prevention of the disease.Methods The epidemiological and clinical information of 15 cases of human infection with avian influenza A (H7N9)reported from April, 2013 to May,2015 were collected.Sample of patients and external environmental samples of suspected exposure were collected and detected by real-time PCR.The epidemic distribution and clinical characteristics were analyzed.Results Fifteen cases of human infection with H7N9 were confirmed from April,2013 to May,2015,including 11 cases of death (77.33%).The confirmed cases mostly reported in winter and spring,and 9 confirmed cases were over 60 years,and male case proportion was higher than women (1.5∶1 ).Most of cases (66.67%)were sporadic and occurred in rural areas,but no epidemiological association was observed among the cases.Fever (100%),cough (66.67%),and wheezing and tightness in chest (33.33%)were common initial symptoms.The chest imaging examination of patients showed ground glass opacity and patchy consolidation,and 7 cases had simple pleural effusion.Twelve of confirmed cases had other chronic diseases.Eleven cases of death had appeared multiple medical comorbidities,such as respiratory failure (6/1 1 ),pulmonary embolism (4/1 1 ),multiple systemic organ failure (3/1 1 ),and heart cerebrovascular embolization (2/11).Twelve cases had been exposed to the live poultry markets where the positive rate of novel influenza A (H7N9) virus in environmental specimens was 7.69%(25/325).One of the 252 close contacts to confirmed cases appeared mild flu-like symptoms.No positive result related to novel influenza A (H7N9)virus nucleic acid was detected from each close contact's throat swabs.Conclusion Human infections with avian influenza A (H7N9)virus showed obvious seasonal distribution in Jiaxing.Elderly men,especially those with chronic diseases were the high risk people of human infection with H7N9 avian influenza.The infection might be associated with the exposure to live birds.Standard management of live poultry markets is the key measure in preventing and controlling H7N9 virus infection among population.