急性胃肠炎病毒课件

1、Gastrointestinal Viruses急性胃肠炎病毒1Gastrointestinal Viruses急性胃肠炎病Viral GastroenteritisIt 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, vira

2、l 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. 急性胃肠炎病毒2Viral GastroenteritisIt is thAssociated with gastroenter

3、itisRotavirusesAdenoviruses 40 41Caliciviruses嵌杯病毒Norwalk like viruses or SRSV (Small Round Structured Viruses)AstrovirusesSRV (Small Round Viruses)CoronavirusesToroviruses急性胃肠炎病毒3Associated with gastroenteritiFound in the gut, not normally associated with gastroenteritisPolioCoxsackie ACoxsackie BE

4、choEnteroviruses 68-71Hepatitis AHepatitis EAdenoviruses 1-39Reoviruses急性胃肠炎病毒4Found in the gut, not normallyFound in the gut as opportunistic infectionCMVHSVVZVHIV急性胃肠炎病毒5Found in the gut as opportunisGastrointestinal VirusesVirusGenomeTypical diseaseincubationDuration Rotaviruses:Group A, B, Cds-s

5、egmented RNA Major cause of diarrhea in children1-3 days24-56 h5-8 days3-7 daysCalicivirusesNorwalk agentsssRNAInfects adults and childrenEpidemic viral gastroenteritis1-3 days18-24 h1-3 days12-48 hEAd 40,41Linear dsRNA diarrhea in children 7-8 days 8-12 d Astrovirus+ssRNAInfects mainly children and

6、 elderly1-4 days1-4 d急性胃肠炎病毒6Gastrointestinal VirusesVirusGGastrointestinal VirusesInfants: Rotavirus A; Adenovirus 40,41; Coxsackie A24 virusInfants, children, and adults Norwalk virus; Calicivirus嵌杯病毒; astrovirus; Rotavirus B; Reovirus.急性胃肠炎病毒7Gastrointestinal VirusesInfantHuman Rotavirus急性胃肠炎病毒8H

7、uman Rotavirus急性胃肠炎病毒8Important Characteristics70 nm round, double shelled, enclosing a genome of 11 segments of double stranded RNA.急性胃肠炎病毒9Important Characteristics70 nm急性胃肠炎病毒10急性胃肠炎病毒10Groups of Rotaviruses Group A subtypes 1, 2, 3, 4 (main human pathogens)(Further 7 subtypes) also infect animal

8、s (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 急性胃肠炎病毒11Groups of Rotaviruses Group A 急性胃肠炎病毒12急性胃肠炎病毒12PathogenesisEssentially an ingestion disease (fa

9、ecal-oral route) Incubation is short : 1 to 3 daysIllness: 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.急性

10、胃肠炎病毒13PathogenesisEssentially an ingPathogenesisGroup A: Main pathogen of infantile diarrheaGroup B : Cause epidemic adult diarrheaGroup C: Cause human or animal sporadic diarrhea急性胃肠炎病毒14PathogenesisGroup A: Main path急性胃肠炎病毒15急性胃肠炎病毒15Immunity:sIgALab. DiagnosisIEM, Cell culture,PAGE of RNA segmen

11、ts,PCRLatex agglutination ELISA 急性胃肠炎病毒16Immunity:sIgALab. Diagnosis急性胃Treatmenttreatment of dehydration by oral and/or intravenous fluids and electrolytes急性胃肠炎病毒17Treatmenttreatment of dehydratPreventionNon specific factors: improved hygiene, education, clean waterSpecific - Breast feeding helps to

12、 provide passive immunity in the newborn (from maternal antibodies), Vaccination is still experimental. 急性胃肠炎病毒18PreventionNon specific factorsEnteric AdenovirusesNaked DNA viruses, 75 nm in diameter. Fastidious enteric adenovirus types 40 and 41 are associated with gastroenteritis.Associated with c

13、ases 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 rotavirusesMost people have antibodies against enteric adenoviruses by the age of thr

14、ee.Diagnosed by electron microscopy or by the detection of adenovirus antigens in faeces by ELISA or other assays.急性胃肠炎病毒19Enteric AdenovirusesNaked DNA AstrovirusesSmall RNA viruses, named because of star-shaped surface morphology, 28 nm in diameter.Associated with cases of endemic gastroenteritis,

15、 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.急性胃

16、肠炎病毒20AstrovirusesSmall RNA virusesCalicivirusesSmall 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, vomitin

17、g 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.急性胃肠炎病毒21CalicivirusesSmall RNA virusesNorwalk-like VirusesSmall RNA viruses, with ragged surf

18、ace, 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 wi

19、nter 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.急性胃肠炎病毒22Norwalk-like VirusesSmall RNA急性胃肠炎病毒23急性胃肠炎病毒23Other Possible Diarrhoeal VirusesCoronavirusesRNA viruses with a crown-like appearanceNot convincing associated with gastroenteritis at presentSmall Round VirusesSmall virus-like particles with a smooth surface, 22-28n