11b: course of infection

Question 1

Virus multiplication:

Answer 1

• effect on the cell

- effect on the host organism –> course of the disease

Question 2

Parameters of virus infections:

Answer 2

• presence of infectious virions in the host; intracellular and extracellular (virus multiplication)
• shedding of infective virions; spread of virus in the population
• clinical signs (disease)
• immune response (serum antibodies)

Question 3

Types of virus infections:

Answer 3

• Acute infections

- Chronic infections (latent infection, tolerated infection, persisting infection, slow infection)

Question 4

Acute infections:

Answer 4

i. e parvoenteriits, influenza

- outcome: recovery, death, chronic infection

Question 5

Latent infection:

Answer 5

i. e Aujeszky´s disease, herpes simplex
- acute phase, latent phase, reactivation
- -> immunosuppression

Question 6

Tolerated infection:

Answer 6

i. e BVD, rubella
- infection at the 2nd trimester of pregnancy –> self-recognition phase.
- virus antigen is regarded as own; No immune response, continuous shedding.

Question 7

Persisting infection:

Answer 7

i. e African swine fever.
* hidden neutralization antigen
- -> Ig is not effective
- clinical signs
- -> immunocomplex deposition

• hidden virus
• equine arteritis: stallin veneral tract
• foot and mouth disease: lymphoid tissue
• canine distemper: CNS

Question 8

Slow infection:

Answer 8

• Retroviruses (Eq. anemia v., HIV)
• integration into the genome
• antigenic changes
• destruction of the immune system
• prions
• not immunogenic, usually no shedding in living animal