10. Olds (1st exam 2020)

Question 2

In tabular form, differentiate ASF virus, parvovirus, coronavirus in terms of
(a) type
(b) confirmation of NA
(c) enveloped or nonenveloped
(d) rank them according to the genomic size with #1 as biggest

Question 3

List down the first and last steps of the typical viral replication cycle.

Question 4

Draw and briefly discuss how antibodies neutralize viruses and lose its infectivity.

Question 5

Make a flowchart of how group 2 viruses from mRNA from their genomic NA. Label the
enzymes and their products.

Question 6

Give 2 possible reasons why infection of PEDV is more severe in native young piglets
that native adult pigs.

Answer 6

a. Attacks the intestinal villous enterocytes
b. ??

Question 7

Cross sectional study from pigs and serological data for PRRS are as follows:
Week 3 = 0.7
Week 6 = 0.5
Week 13 = 0.2
Week 15 = 1.9
Week 19 = 2.7

Values >0.4 is + .
(a) Abs at wk 3 and 6 is due to?
(b) Justify your answer in “a”
(c) Give 2 possible reasons why the Abs at wk 15 is increased.

Answer 7

(a) Maternal Abs
(b) From birth up to 16 weeks of age, maternal Abs can stay in the body of young animals. At a younger age, the maternal Abs are of greater number and gradually subside as the animals age.
(c) Infection or vaccine response

Question 8

(a) Describe AIAO management system in farms. (b) Give 2 reasons why AIAO is better than continuous management system in terms of viral disease and control.

Answer 8

(a) AIAO - All in all out system - animal houses are emptied, cleaned and disinfected in between groups of animals

(b) Allows for cleaning of building before entry of new batch of animals (this answer specifically in module). Effectiveness of disinfectants are greatly influenced by access and time of exposure, more time spent disinfecting, more effective (this answer not specifically in module)

Question 9

What is residual virulence and what is its disadvantage in attenuated vaccines?

Answer 9

Disadvantage
○ under attenuation leads to virulence and disease
○ Risk of reversion to virulence after administration of vaccine (since vaccine is replication-competent)

Advantage (hindi natanong)
○ Activate a wide range of immune response
○ Long lasting and rapid onset of immunity
○ Reduce the need for booster
○ Do not need adjuvants
○ Low cost
○ Can be administered via oral route

Question 10

Draw and briefly discuss how NK cells
(a) recognize infected cells and
(b) kill virus-stress infected cells.

Label your drawing.

Answer 10

DRAWING

a. Recognize thru the Fc region of IgG tapos merong Fc receptors yung i8NK cells na magbind sa IgG

b. Kapag nagbind na, granzymes of NK cells will create a hole and allow insertion of perforins. The entry then causes the cell to perform or commit apoptosis leading to its destruction.

Question 11

BONUS: What is the major factor that affects or influences the endemic and epizootic
infections of Rift Valley Fever in Africa?

Answer 11

Heavy rainfall and flooding causes the infected aedes species to multiply, causing a rise in infection of the animals (mainly cattle)

Question 12

Why you can find parvovirus microscopically in cytoplasm

Answer 12

• Attachment to receptor➡️endocytosis of the virion to the host cell.
• Virion penetrates into cytoplasm (permeabilization) and reaches the nucleus where uncoating occurs (microtubular transport)

Question 13

Draw cycle of PCR

Question 14

DRAW Immunochromatography LFD