VIRAL GASTROENTERITIS

Viruses associated with gastroenteritis

Etiologic agents in severe diarrheal illnesses requiring H of infants & young children Other viruses;

Coronaviruses ,Toroviruses & Enteroviruses

Epidemiology

Distribution ; Worldwide in poor hygiene, overcrowding, and

poverty

Age ; Infants & young>>Older children

Transmission ; Faecal-oral route

Season ; Winter months

Endemic inf ; Gp A rota & adeno 40,41

Epidemic inf ; Norovirus

VGE

Clinical Features VGE

IP ;ShortSymptoms:

D, V, Fever & abdominal cramps

Dehydration with Na Life threateningWinter vomiting disease:

Vomiting > Diarrhoea Calicivirus

VGE

Cell culture: [c/c]

Fastidious growing poorly not used

Electron microscopy: [EM]

Catch all techMany disadvantages not used

Specific test:ELISA for detection of viral ags in stool

[rota , adeno , astro & caliciviruses]

Lab diagnosis

VGE

Treatment:Rehydration

Prevention: Sanitation & hygiene measures

No vaccines except for rotavirus

Management

ROTAVIRUSFamily:

Reoviridae [Respiratory& Enteric Orphan]

Description:11 segments dsRNADouble-layered icosahedralNonenveloped

~ 70 nmRNA – dependent RNA polymerase

7 groups [A-G]----- GpA most common

EpidemiologyRota

Rota

Spread:Faecal-oral route

Age: all age groupsSymptomatic inf ;

6 -24 M

Peak ; Winter months

Inf ; Endemic

RotaRota

Pathogenesis

Clinical featuresRota

Rota

Intestinal inf:Infants & young children

gastroenteritis or infantile GE IP = 1-2 dsWatery, nonbloody D,V & FDehydrationOutcomes Vary

~1/2 of all GE cases AdmissionIn developed count. Mortality is lowIn developing count. Mortality is sig

Deaths reported

Clinical featuresRota

Rota

Intestinal inf:Infants & young children GEOlder children+ adults asymptomaticImmuno ed hosts chronic D

Extra-intestinal inf:Encephalitis small n.

Rota

Rota

Sample; stool Immunoassay Most used

ELISA & latex agglutination (gp A rotavirus Ag)

EMGel electrophoresisRT.PCRCell culture

Diagnosis

Rota

Rota

ManagementTreatment:

Rehydration

Prevention:Sanitation & hygiene measuresVaccine; LAV, oral

Rotashield ( withdrawn)RotarixRotaTeq

ENTERIC ADENOVIRUSESFamily: AdenoviridaeDescription:

Nonenveloped, icosahedral,dsDNAOnly V with a fiber protruding from each of

the vertices of the capsid Fiber Attachment

Hemagglutinin

Type-specific ag

ENTERIC ADENOVIRUSESClassification:

Adenovirus 6 subgenera[A-F]

51 serotypes Grow in C/C

Enteric adenoviruses Subgenus F 40&41serotypes

Fastidious

ENTERIC ADENOVIRUSESClinical feature:

Longer IP Less severe than rotavirusProlonged illness

Diagnosis:Ag detection in stool by ELISA

CalicivirusesFamily ; Caliciviridae [Calyx =cup]

Description :NonenvelopedssRNA,+ve polarityIcosahedral

Two morphologic typesTypical caliciviruses (Sapoviruses)Small Rounded Structured Viruses . (Noroviruses)

EpidemiologyFaecal-oral route [water, shellfish]Outbreaks of GE in schools, camps &cruiseAll age gps

Clinical featuresChildren vomiting [projectile]Adults diarrhea

DiagnosisViral Ag in stool by ELISA

NOROVIRUS(Norwalk virus)

Astroviruses

Family; Astroviridae [astro= a star]

Description:NonenvelopedssRNA,+ve polarityIcosahedral

8 serotypes

AstrovirusesClinical featuresMild GEOutbreak of diarrhea <5 ys

Lab. Diagnosis:Ag detection in stool by ELISA

عنه الله رضي هريره أبي عن: قال وسلم عليه الله صلي الله رسول أن

اللسان , } على خفيفتان كلمتانالميزان في ثقيلتان

الرحمن إلي : حبيبتان

سبحان الله وبحمده ,

سبحان الله

{العظيم