1. VIRAL GASTROENTERITIS

2. VIRAL GASTROENTERITIS
ROTAVIRUS
Linear ds RNA, 11 segments, with 70 nm diameter
ADENOVIRUS
Linear ds DNA, with 80 – 110 nm diameter
Types 40 and 41
CALICIVIRUS
Linear positive sense ss RNA, with 35 nm diameter
Norovirus causes diarrhea
Hepatitis E virus causes hepatitis
ASTROVIRUS
Linear positive sense ss RNA, with 30 nm diameter

3. ROTAVIRUSES
DISEASES
Gastroenteritis (diarrhea), especially in young children

4. PROPERTIES
Member of the Reovirus family (reo; respiratory enteric orphan)
Non-enveloped, dsRNA viruses with icosahedral symmetry
11 segments RNA
RNA-dependent RNA polymerase (human cells do not have an RNA polymerase that can synthesize mRNA from double-stranded RNA template)
The capsid has double shell
6 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. PATHOGENESIS
Rotavirus 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 diarrhea
Dehydration is the main complication

8. LABORATORY DIAGNOSIS
Detection of rotavirus in the stool by ELISA or RIA
Latex agglutination
Immunoelectron microscopy

9. ROTAVIRUSES

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.

11. ADENOVIRUSES

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 stool
Isolation of the virus in cell culture
Detection 4-fold or greater increase in antibody titre

13. ADENOVIRUSES

14. NOROVIRUS

15. NOROVIRUS Calicivirus Naked icosahedral capsid
ssRNA, linear, non-segmented with positive polarity

16. NOROVIRUS
Causes 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 infection
People with blood group B has decreased risk of infection
Transmission: fecal-oral, sewage-polluted water supply, shellfish taken from contaminated water.
Diagnosis: detection of viral antigen in stool using ELISA.

17. ASTROVIRUS

18. ASTROVIRUS Linear, positive sense ssRNA virus
The surface of the icosahedral capsid has five or six-pointed star appearance.

19. ASTROVIRUS Causes outbreaks of diarrhea in children under 5 years
Mild gastroenteritis, fecal-oral transmission
Diagnosis: detection of viral antigen