2 VIRAL GASTROENTERITIS ROTAVIRUSLinear ds RNA, 11 segments, with 70 nm diameterADENOVIRUSLinear ds DNA, with 80 – 110 nm diameterTypes 40 and 41CALICIVIRUSLinear positive sense ss RNA, with 35 nm diameterNorovirus causes diarrheaHepatitis E virus causes hepatitisASTROVIRUSLinear positive sense ss RNA, with 30 nm diameter
3 ROTAVIRUSESDISEASESGastroenteritis (diarrhea), especially in young children
4 PROPERTIESMember of the Reovirus family (reo; respiratory enteric orphan)Non-enveloped, dsRNA viruses with icosahedral symmetry11 segments RNARNA-dependent RNA polymerase (human cells do not have an RNA polymerase that can synthesize mRNA from double-stranded RNA template)The capsid has double shell6 serotypes (A-F)
5 TRANSMISSION Fecal-oral route Season: winter By age of 6 years, the majority of children have antibodies to at least one serotype.
6 PATHOGENESISRotavirus replicates in the mucosal cells of the small intestine, damaging the transport mechanisms with consequent loss of fluids and electrolytes.No inflammation occurs and the diarrhea is non-bloody.
7 CLINICAL FINDINGS Babies under 2 years are the main victims. Nausea, vomiting and watery, non-bloody diarrheaDehydration is the main complication
8 LABORATORY DIAGNOSISDetection of rotavirus in the stool by ELISA or RIALatex agglutinationImmunoelectron microscopy
10 TREATMENT No antiviral drug is available. Rehydration Rotavirus vaccine (RotaShield) contains four serotypes of live, attenuated virus. In 1999, a hold was placed on the vaccine because of the risk of intussusception.
12 ADENOVIRUSES Non-enveloped DNA virus with icosahedral capsid Adenovirus is the only virus with a fiber protruding from each of the 12 vertices of the capsid. The fiber is the organ of attachment and is a hemagglutinin.There are 41 known antigenic serotypes; the fiber protein is main type-specific antigen.Types 40 and 41 cause infantile gastroenteritis.Laboratory diagnosis:Adenovirus antigen detection in patient’s stoolIsolation of the virus in cell cultureDetection 4-fold or greater increase in antibody titre
16 NOROVIRUSCauses outbreaks of gastroenteritis in schools, camps and cruise ships.Previously named Norwalk virus for an outbreak in school in Norwalk, Ohio in 1969.Children tend to suffer from extensive vomiting, while adults are more likely to experience diarrhea.Infection susceptibility:People with blood group O has increased risk of infectionPeople with blood group B has decreased risk of infectionTransmission: fecal-oral, sewage-polluted water supply, shellfish taken from contaminated water.Diagnosis: detection of viral antigen in stool using ELISA.