Rotaviruses, Reoviruses, Coltiviruses, and Orbiviruses

1. Rotaviruses, Reoviruses,Coltiviruses, and Orbiviruses fackrel@Uwindsor.ca

2. REO Viruses • Structure • Classification • Multiplication • Clinical manifestations • Epidemiology • Diagnosis • Control Baron’s Web Site

3. Rota virus: Structure • wheel-shaped particles • double-layered icosahedral capsid enclosing a core particle

4. 11 segments of double-stranded RNA, each segment representing one gene. Genome

5. Rotavirus antigenic specificities • Group • Group A major pathogens in humans and animals • groups B and C found in humans; • not important pathogens • Subgroup • Serotype • neutralization of one (VP7) of the two outer capsid proteins..

6. RotavirusClinical manifestations • enteric disease • diarrhea, vomiting, abdominal discomfort, and fever • mainly infants and young children. • May cause fatal dehydration.

9. 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.

10. 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

11. Norwalk-like viruses 23,000,000 Rotavirus 3,900,000 Astrovirus 3,900,000 Hepatitis A 83,391 Total Viral food borne 30,883,391 Total Microbial food borne incidence 38,629,64 Annual Incidence Viral food borne diseases CDC

12. Rotavirus Diagnosis • Clinical findings are nonspecific • Detect virus in feces (e.g., by immunoassay) • Demonstrate a serum antibody response

13. Rotavirus: Control • Dehydration is treated by fluid and electrolyte replacement. • Vaccine development is under way and appears promising

14. DONE!!!