Rotaviruses, Reoviruses, Coltiviruses, and Orbiviruses
REO Viruses
Rota virus: Structure
- wheel-shaped particles
- double-layered icosahedral capsid enclosing a core particle
Genome
- 11 segments of double-stranded RNA, each segment representing one gene.
Rotavirus antigenic specificities
- Group
- Group A major pathogens in humans and animals
- groups B and C found in humans;
- not important pathogens
- Serotype
- neutralization of one (VP7) of the two outer capsid proteins..
Rotavirus Clinical manifestations
- enteric disease
- diarrhea, vomiting, abdominal discomfort, and fever
- mainly infants and young children.
- May cause fatal dehydration.
PPT Slide
PPT Slide
REO virus: Multiplication
- Endocytosis
- direct membrane penetration if activated by protease
- Replicates in the cytoplasm.
- Removal of the outer shell of the capsid in lysosomes activates the viral RNA polymerase.
- Outer capsid proteins acquired by budding through the endoplasmic reticulum,
- Virions are released by cell lysis.
Rotavirus Epidemiology
- Group A rotaviruses are ubiquitous and infect most individuals by the third year of life.
- Single most important cause of severe diarrhea in infants and young children
- 30 to 50 % of cases requiring hospitalization or treatment.
- In temperate climates, incidence peaks in the winter; in the tropics, the disease occurs year-round
Annual Incidence Viral food borne diseases
- Total Viral food borne 30,883,391
- Total Microbial food borne incidence
Rotavirus Diagnosis
- Clinical findings are nonspecific
- Detect virus in feces (e.g., by immunoassay)
- Demonstrate a serum antibody response
Rotavirus: Control
- Dehydration is treated by fluid and electrolyte replacement.
- Vaccine development is under way and appears promising
DONE!!!