REOVIRIDAE

Question 1

Genera

Answer 1

(Reo=Respiratory Enteric Orphan)
4- Genera

1. Orthreo - Strong
2. Orbi - Weak
3. Colti - Weak
4. Rotavirus - Strong

Question 2

Morphology

Answer 2

Non-enveloped
Icosahedral Double capsid
(10-12) dsRNA

Question 3

Replication

Answer 3

• Baltimore III
• In the cytoplasm of host cells
• Use viral transcriptase
• Form intracytoplasmic inclusion bodies

Question 4

Biological properties

Answer 4

• Orbivirus and coltivirus = Arthropod bourne
• Orthoreo virus forms:
  
  • Cytoplasmic occlusion bodies and
  • Cell rounding
• Orthoreovirus and Rotavirus:
• are hard to propagate invitro
• Orbi and coti - Arboviruses (mosquitos etc)

Question 5

Antigenic Properties

Answer 5

• Good antigens
• Form Cross reactions
  (AG and AB reaction)

Question 6

Diagnosis

Answer 6

1. Isolation
2. Animal experimentation :(
3. IF- Immuno-flourescence technique
4. EM

Question 7

Orthoreovirus

Answer 7

1. Mamillian Reoviruses 1-3: Pnumoenteritis
   - Mild enteric and
   - Pnumoenteritis - Respiratory disease
   - Euryxenous
   (wide host range from Humans, Dogs, foals, Calves ect)
2. Avian reoviruses:
   = “Helicopter disease”
   = “Ranting/stunning syndrome

• Several strains,
• Important cause of:
  
  • arthritis/tenosynovitis in chickens.

Question 8

Orbivirus (orbis=circle)

Answer 8

1. African horse sickness:
   - Edema,
   - hemorrhage,
   - pneumonia,

Arthropod bourne disease with high mortality.

2. Bluetongue virus: ABORT, CYAN, EDEMA
   - Cyanosis,
   - edema in sheep and cattle.

Arthropod Bourne.

3. Ibaraki disease: CATTLE ABORTION
   - Similar to bluetongue.
   - Causes abortion.
   - Member of the epizootic haemorrhagic disease virus group.
4. Equine encephalosis (s.africa)

Question 9

Colti Virus

Answer 9

Colarodo tick fever virus:

• Human fever, rash.
• Roden species act as carriers.
• Arthropod bourne in ticks and mosquitoes.

Question 10

Rotavirus

Answer 10

(rota=wheel)
Neonatal enteritis (E.coli): 
- In calves,
  piglets, 
  children