急性胃肠炎病毒e课件

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Gastrointestinal Viruses,Gastrointestinal Viruses,Viral Gastroenteritis,It is thought that viruses are responsible for up to,3/4,of all infective diarrhoeas.,Viral gastroenteritis is the second most common viral illness after upper respiratory tract infection.,In developing countries, viral gastroenteritis is a major killer of infants who are undernourished. Rotaviruses are responsible for half a million deaths a year.,Many different types of viruses are found in the gut but only some are associated with gastroenteritis.,Viral GastroenteritisIt is th,Associated with gastroenteritis,Rotaviruses,Adenoviruses 40 41,Caliciviruses,嵌杯病毒,Norwalk like viruses or SRSV (Small Round Structured Viruses),Astroviruses,SRV (Small Round Viruses),Coronaviruses,Toroviruses,Associated with gastroenteriti,Found in the gut, not normally associated with gastroenteritis,Polio,Coxsackie A,Coxsackie B,Echo,Enteroviruses 68-71,Hepatitis A,Hepatitis E,Adenoviruses 1-39,Reoviruses,Found in the gut, not normally,Found in the gut as opportunistic infection,CMV,HSV,VZV,HIV,Found in the gut as opportunis,Gastrointestinal Viruses,Virus,Genome,Typical disease,incubation,Duration,Rotaviruses:,Group A, B, C,ds-segmented RNA,Major cause of diarrhea in children,1-3 days,24-56 h,5-8 days,3-7 days,Caliciviruses,Norwalk agents,ssRNA,Infects adults and children,Epidemic viral gastroenteritis,1-3 days,18-24 h,1-3 days,12-48 h,EAd 40,41,Linear dsRNA,diarrhea in children,7-8 days,8-12 d,Astrovirus,+ssRNA,Infects mainly children and elderly,1-4 days,1-4 d,Gastrointestinal VirusesVirusG,Gastrointestinal Viruses,Infants:,Rotavirus A; Adenovirus 40,41; Coxsackie A24 virus,Infants, children, and adults,Norwalk virus; Calicivirus,嵌杯病毒,; astrovirus; Rotavirus B; Reovirus.,Gastrointestinal VirusesInfant,Human Rotavirus,Human Rotavirus,Important Characteristics,70 nm round,double shelled, enclosing a genome of,11,segments of double stranded RNA,.,Important Characteristics70 nm,急性胃肠炎病毒e课件,Groups of Rotaviruses,Group A,subtypes 1, 2, 3, 4 (main human pathogens)(Further 7 subtypes) also infect animals (monkey, calf, mouse),Group B,Infects pigs and ratsFound to cause extensive outbreaks in China in past decade,Group C,Infects Pigs (Occasionally Man),Group D,Infects birds,Group E,Infects pigs,Groups of Rotaviruses Group A,急性胃肠炎病毒e课件,Pathogenesis,Essentially an ingestion disease (faecal-oral route),Incubation,is short :,1 to 3 days,Illness:,Sudden onset watery diarrhoea, with or without vomiting.,May last up to 6 days,(or longer if immunocompromised). The disease is self limiting.,Complications:,Dehydration may result, this can be severe and life threatening in young children.,PathogenesisEssentially an ing,Pathogenesis,Group A: Main pathogen of infantile diarrhea,Group B : Cause epidemic adult diarrhea,Group C: Cause human or animal sporadic diarrhea,PathogenesisGroup A: Main path,急性胃肠炎病毒e课件,Immunity,:,sIgA,Lab. Diagnosis,IEM,Cell culture,PAGE of RNA segments,PCR,Latex agglutination,ELISA,Immunity:sIgALab. Diagnosis,T,reatment,treatment of dehydration,by oral and/or intravenous fluids and electrolytes,Treatmenttreatment of dehydrat,Prevention,Non specific factors:,improved hygiene, education, clean water,Specific,- Breast feeding helps to provide passive immunity in the newborn (from maternal antibodies), Vaccination is still experimental.,PreventionNon specific factors,Enteric Adenoviruses,Naked DNA viruses, 75 nm in diameter.,Fastidious enteric adenovirus types 40 and 41 are associated with gastroenteritis.,Associated with cases of,endemic gastroenteritis, usually in young children and neonates. Can cause occasional outbreaks.,Possibly the second most common viral cause of gastroenteritis (7-15% of all endemic cases).,Similar disease to rotaviruses,Most people have antibodies against enteric adenoviruses by the age of three.,Diagnosed by electron microscopy or by the detection of adenovirus antigens in faeces by ELISA or other assays.,Enteric AdenovirusesNaked DNA,Astroviruses,Small RNA viruses, named because of star-shaped surface morphology, 28 nm in diameter.,Associated with cases of,endemic gastroenteritis, usually in young children and neonates. Can cause occasional outbreaks.,Responsible for up to 10% of cases of gastroenteritis.,Similar disease to rota and adenoviruses.,Most people have antibodies by the age of three.,Diagnosed by electron microscopy only, often,very difficult because of small size.,AstrovirusesSmall RNA viruses,Caliciviruses,Small RNA viruses, characteristic surface morphology consisting of hollows. particles 35 nm in diameter.,Associated mainly with epidemic outbreaks of gastroenteritis, although occasionally responsible for endemic cases.,Like Norwalk type viruses, vomiting is the prominent feature of disease.,Majority of children have antibodies against caliciviruses by the age of three.,Diagnosed by electron microscopy only, often difficult to diagnose because of small size.,CalicivirusesSmall RNA viruses,Norwalk-like Viruses,Small RNA viruses, with ragged surface, 35 nm in diameter, now classified as caliciviruses.,Always associated with epidemic outbreaks of gastroenteritis, adults more commonly affected than children,.,Associated with consumption of shellfish and other contaminated foods. Aerosol spread possible as well as faecal-oral spread.,Also named winter vomiting disease, with vomiting being the prominent symptom, diarrhoea usually mild.,Antibodies acquired later in life, in the US, only 50% of adults are seropositive by the age of 50.,Diagnosis is made by electron microscopy and by PCR.,Norwalk-like VirusesSmall RNA,急性胃肠炎病毒e课件,Other Possible Diarrhoeal Viruses,Coronaviruses,RNA viruses with a crown-like appearance,Not convincing associated with gastroenteritis at present,Small Round Viruses,Small virus-like particles with a smooth surface, 22-28nm in diameter,May possibly be parvoviruses, enteroviruses, or cubic bacteriophages,Occasionally seen in the faeces of endemic or epidemic cases of gastroenteritis,Other Possible Diarrhoeal Viru,Gastrointestinal Viruses,Virus,Genome,Typical disease,incubation,Duration,Rotaviruses:,Group A, B, C,ds-segmented RNA,Major cause of diarrhea in children,1-3 days,24-56 h,5-8 days,3-7 days,Caliciviruses,Norwalk agents,ssRNA,Infects adults and children,Epidemic viral gastroenteritis,1-3 days,18-24 h,1-3 days,12-48 h,EAd 40,41,Linear dsRNA,diarrhea in children,7-8 days,8-12 d,Astrovirus,+ssRNA,Infects mainly children and elderly,1-4 days,1-4 d,Gastrointestinal VirusesVirusG,