禽流感：预防和控制策略.pdf

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1、Avian Influenza:Strategies for Prevention&ControlCSingaporeOutlines Introduction Virus Biology&AIV Current Status Epidemiology&Transmission Disease,Pathology&Diagnosis Control&Prevention Strategies Human Infections EpilogueGlobal AI Situation:January 2022 March 2023Virus Biology&AIV StatusPotentiall

2、y there is possible Combination from H and N=144H and N are important in virus entry&exit from the host cell&interaction between virus&host cellsAvian Influenza VirusesImportant Avian Influenza VirusesAIV Pathotypes&Virus PathogenicityLPAI(H9)HPAI(H5/H7)HPAI Asia Situationwww.Pirbright.ac.ukCurrentl

3、y H5N1 Clade 2.3.4.4b Viruses dominate Globally(77 countries)Domestic bird outbreaks:not reported from endemic countriesMunir Iqbal (2024)Global AI(H9N2)StatusThree stable HA lineages:G1-WGroup AGroup BGroup CGroup D Beijing(BJ94/Y280)Korean-like(Y439)Few studies on AntigenicityPeacock et al.,Viruse

4、s(2019)AI subtype H9N2 is endemic in many bird species in Asia&the Middle East.Virus has occasionally crossing species barrier to mammals including human beings.H9 subtype viruses are NOT Notifiable to OIE:possible under-reporting on actual field situations.Epidemiology&TransmissionAIV can infect a

5、variety of Domestic&Wild Avian Species(including chickens,turkeys,ducks,domestic geese,quail,pheasants,psittassines,gulls,shorebirds,emu&others).The clinical manifestation of infection ranges from asymptomatic infection to rapidly fatal diseaseAquatic birds,particularly Ducks,Shore Birds&considered

6、the Natural Reservoirs These waterfowl generally do not develop disease when infected with AI viruses.Recently,investigators in Asia have shown that asymptomatically infected domestic ducks are shedding more H5N1 to domestic poultry(references:FAO/OIE/WHO 2004)Avian Influenza Virus:The HostsInfluenz