Topic 17: Types of viral infections

Question 1

What are the types of viral infections?

Answer 1

1. Virus multiplication
2. Parameters
3. Acute infections
4. Chronic infections
5. Persisting infections
6. Slow infections

Question 2

What is the virus multiplication?

Answer 2

Effect on the cell and host organism

-> Dictates the course of the disease

Question 3

What is the parameters ?

Answer 3

1. Presence of infected virons in host:
   - IC /EC
2. Shedding or Infective
   - Virons: increase or decrease spreading
3. Clinical symptoms of disease
4. Immune response - AntiB produced

Question 4

What is chronic infections?

Answer 4

1. Latent infection
   - a secondary infection after immune resp.
   (reactivation)
   * Aujesky disease
   * Herpes simplex
2. Tollerated infection
   - Infection occurs 2nd trimester of pregnancy
   - Self recognition phase
   * BVD
   * Rubella

Question 5

What is persistent infections?

Answer 5

AFRICAN SWINE FEVER

1. Hidden neutralisation antigen
   - IG is not effective
   - Imuno-complex deposition
2. Hidden virus
   * Equine arteritis - stallion venereal tract
   * Foot and Mouth - Lymph tissue
   * Canine distemper - CNS

Question 6

What is acute infections?

Answer 6

PARVOENTERITIS, INFLUENZA

1. Virus multiplies in a normal distribution
2. Shows clinically signs at peak
3. Delayed immune response
   - recover/death (or chronic infection)

Question 7

What is slow infections?

Answer 7

1. Retrovirus
Integrated into genome
- Antigenic changes
- Immune system destroyed
* Equine anaemia
* Aids

2. Prions
   - Non immunogenic
   - No shedding occurs in living animals