Identification

Question 1

Name the reasons why we would need to reach a diagnosis at the individual or herd level or at the national level

Answer 1

1) for diseases in which management of the animal or its prognosis is influenced by the diagnosis
2) certification of freedom from specific infections
3) AI, embryo transfer and blood transfusion
4) zoonosis
5) xenotransplantation for humans

Question 2

Discuss why is it important for the practicing veterinarian to collect and transport samples correctly

Answer 2

Increases the chances of a virus being isolated

Don’t place tissues in formalin if you’re planning on looking for a virus

Question 3

Should samples be frozen?

Answer 3

NO. Just keep cold and moist.

Question 4

List the desired characteristics for diagnostic tests

Answer 4

fast, simple, sensitive, specific and low cost

Question 5

Explain what is sensitivity and specificity of a diagnostic test

Answer 5

Sensitivity: the percentage of animals with the disease that test positive

Specificity: the percentage of animals without the disease that test negative

Question 6

Define what is a direct method and which methods are available in virology

Answer 6

Electron microscopy
Immune electron microscopy-classic immune and solid phase
Antigen detection-ELISA
Viral genome detection-PCR

Question 7

Define indirect methods and which methods are available in virology

Answer 7

Cell culture
embryonated egg
Neonate mice
Serology

Question 8

Cell culture

Answer 8

• For diagnostic purposes/research/vaccine production.
• Propogate viruses
• 1* cell line
• semi-continuous
• continous cell line

Question 9

How to confirm the ID of a virus?

Answer 9

1) neutralization
2) Hemadsorption-inhibition
3) IF tests

Question 10

Serology Primary Infection

Answer 10

seroconversion is 4 fold between acute and convalescent sera (paired samples)
IgM present

Question 11

Serology Reinfection

Answer 11

seroconversion is 1 fold (between paired samples)

Little to no IgM present

Question 12

Hemagglutination inhibition

Answer 12

viral ABs that prevent viruses from binding to RBC

Question 13

Viral neutralization test

Answer 13

Used to ID and quantify neutralizing ABs.

Used to ID virus grown in cell culture with no CPE

Question 14

List advantages and disadvantages of antigen detection methods

Answer 14

Quick results, easy and cheap

Sometimes has decreased sensitivity and specificity. can be expensive and time consuming.

Question 15

Disadvantages of serology

Answer 15

Have to wait 10-14 days for paired samples to detect seroconversion folds
Mild local infections may not produce a detectable humoral response
cross reactivity may occur
immunocompromised may not seroconvert
Neutralizing abs can only be tested in cell culture