denguefever登革熱-wenkub
2023-04-28 22:49:50 本頁(yè)面
【正文】 virus are maintained in a cycle that involves humans and Aedes aegyptin primarily a disease of the tropicsn OCCURS IN two forms: Dengue fever(DF) Dengue haemorrhagic fever(DHF) Clinical manifestationsn DF: fever, headache, myalgias, bone , skin rash. Leukopenia n DHF: high fever, haemorrhage, hepatomegaly evidences of “l(fā)eaky capillaries” signs of circulatory failure(dengue shock syndrome,DSS.)Why should we learn it ?n 2500 million at risk from dengue per year. n Epidemic in more than 100 countries in Africa, America, Eastern Mediterranean, South –east Asia and the Western pacific. n The global prevalence of DHF grown dramatically in recent decades: 1970/1995:4 fold increase.n The most important mosquitotransmitted viral disease in term of mortality and morbidity.Etiologyn Dengue virus: enveloped RNA virusn Classified : family of Flaviviridae.n Serum type:14n causes closely related illness, severe and fatal disease n but antigenically distinct homotypic immunity: lifelong heterotypic immunity :short period but crossresponse may worsen the second infection by a another serum type. How DF transmitted?n Sources of infection: patients and anyone who with Covert infectionn Transmitted vectors: Aedes aegypti is the most mon vectors other Aedes mosquitos are less effiecitent : , Primarily a daytime feeder Lives around human habitationn The host: all susceptible if never came across dengue fever. How dengue virus cause the disease? (pathogenesis and clinical presentations)Dengue virusBlood streamMononuclearphagocyte system second viremia Antigen antibody plexesplementsystemincubationLymphadenopathy,hepatomeglyBone marrow depressVascular permeability↑Rash, haemarrhagic fever Bone pains,etc Imfllamatory materialsrisk factors for DHFImportant risk factors for DHF includen Virus factors: n the serotype :2 is the predominatingn the strain: virulent strainn Host factors:n geic predispositionn the age n Children : experienced a precious dengue infection n Infants with waning levels of maternal dengue antibody.n immune status: if there are enhancing Ab.Enchancing antibodyA mechanism of DHF/DSS is n heterotypic antibodies n enhancement of virus replication in macrophages n worsen the condition Neutralizing antibody to Dengue 1 virus 11Dengue 1 virus 1Homologous Antib
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