| Avian influenza(AI)is an infection and/or disease syndrome caused the avian influenza virus(AIV).The widespread and continuous evolution of avian influenza threatens the wild bird population and has caused great losses to the poultry industry.Wild birds are the most natural reservoir of avian influenza viruses.According to pathogenic avian influenza can be divided into Low pathogenic avian influenza(LPAI)and High pathogenic avian influenza(HPAI)after infecting with AI.Migratory birds are a huge genetic repository of avian influenza viruses,and their migration behavior poses a huge hazard to the spread of avian influenza.In the 3 main migratory routes of birds in China,the eastern passage is the most important,most water birds migrate through this area.The region has a large north-south span,a clear climate change and a relatively dense population distribution.It is a concentrated area of avian influenza in wild birds.In order to understand the risk and trend of the spread of AI in the migratory route of birds in the eastern part of the country,based on the ecological niche model,geographic information system,correlation analysis and molecular biology,this study analyzed the risk spatial distribution of wild bird avian influenza in the research process,constructing the network of protected areas and put forward management countermeasures,providing scientific basis for early prevention and early warning of avian influenza.The main results are as follows:1.Analysis of meteorological factors affecting the spatial distribution of wild bird AI In order to understand the relationship between the distribution of wildfowl AI caused by the migratory birds in eastern route and meteorological factors,I will take the distribution of wildfowl AI cases from 2006 to 2017 in China to confirm the collection area of meteorological data in eastern China.Under analysis of correlation and principal component of the collected environmental data in different regions,and the selection of environmental factor contribution rate and Receiver Operating Characteristic Curve(ROC)in the Maxent ecological niche model,Judging the importance and scope of the influencing factors.The result came out that the average diurnal,altitude and precipitation in January are 3 factors combined to affect the occurrence of wildfowl AI in the main study area.Among the 3 collected environmental factors,temperature,precipitation and terrain characteristics,the influencing factor in the different research areas are all related to the temperature.That is to say,the occurrence and distribution of wild bird AI have strong feedback and adaption under natural conditions of temperature.Wildfowl AI tend to be distributed is distributed in low temperature,moist and low altitude area.2.Analysis of the risk and trend of wild bird AI in eastern ChinaIn order to understand the development trend of wild bird AI in the migratory route of the eastern China,and for better disease prevention and early warning,this article forecasts the risk of wild bird AI distribution.Three periods(1950?2000,2040?2060,2060?2080)and 4 environmental climate data of Representative Concentration Pathways(RCP)are used to analyze the risk distribution of it.This paper also does the prediction of possible migratory trends of disease by centroid transfer,showing that the AI high risk areas in eastern China mainly concentrated in the region border of three northeastern provinces and the inner Mongolia Autonomous Region,the aeras around Bo Hai,the middle and lower reaches of the Changjiang River,central China and the southern coastal areas.The range of the 4 areas of high incidence of disease,2 future periods and 4 RCP all show the consistent risk migration trend of wildfowl AI,which is transferring the whole to the Southwest.Most aeras of North China,southern foreland,the plain of Hubei and Hunan,the middle and lower reaches of the Changjiang River,the eastern Sichuan basin and other places will become an important potential distribution of wildfowl avian influenza.3.Analysis of susceptibility to avian influenza of ten birds in eastern ChinaThe Mx protein has an anti-disease effect,which can prevent the replication of the virus under certain conditions,and the mutation of its special locus causes the chicken to have a physical change of resistance or susceptibility to the avian influenza virus.I will choose ten representative birds common in eastern China which can be naturally infected by AI as example,amplificating the sequence of exon 14 of the Mx gene,comparing with Chicken's mutant loci that can change the resistance of avian influenza,and also analyzing the selection pressure and evolution of the region.This research completed the amplification of Mx exon 14 sequence of 10 wild birds,encoding 77 amino acids.The specific sites that can cause changes in the body's resistance to avian influenza are serine,that is,all detection birds are susceptible to avian influenza.Test results indicates that the poultry antiviral site S631N are neutral evolution site,compared with GED coding regions in terms of the other sites codon is under less protein structure andeasy to mutate to a certain extent.The Mx genes of measured birds are consistent with the traditional bird evolution sequence,combined with the effects of bird AI reported,this study has shown that the taxonomy between birds in this study is vulnerable to the threat of avian influenza virus.4.Network construction of protected areas for wild bird AI.In order to improve the efficiency of wild bird avian influenza prevention and control on bird migration routes in the east,considering susceptible wild bird species distribution and habitat of population density and the influence of social and economic activities on the habitat factors.According to the demarcated screening conditions,we have obtained 44 nature reserves that require special attention and implementation of prevention and control work,proposed the current management problems of protected area networks,and proposed management strategies for the problems. |
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