Practical Examination

Question 1

What are the basic steps that are involved in an ELISA test?

Answer 1

1. Virus is on the surface 2. Enzyme with an antibody linked conjugate is added and then the sample is washed 3. Add a substrate and together these will create a colour change

Question 2

What are the advantages of SNAP test technology over other systems?

Answer 2

speed, cost, accessibility

Question 3

What are the disadvantages of SNAP test technology over other systems?

Answer 3

less accurate, not as precise

Question 4

What are the different areas that you can inject into when inoculating eggs?

Answer 4

1. Yolk sac 2. Allantois sac/cavity 3. Chorioallantoic membrane

Question 5

Where is the endpoint in viral detection and quantification ?

Answer 5

the point at which partial or complete near agglutination occurs

Question 6

What is the name of the virus below?

Answer 6

measles virus

Question 7

Name the virus in the diagram below:

Answer 7

Anaplasma centrale and anaplamsa marginale

Question 8

What is the name of the virus below?

Answer 8

Babesia

Question 9

What is the process for carrying out a gram stain?

Answer 9

1. Primary stain- crystal violet
2. Mordant-iodine
3. Decolouriser- acetone
4. Counter strain- carbol fushin

Question 10

Is pink gram negative or gram positive?

Answer 10

Pink is gram negative

Question 11

Is purple bacteria gram positive or gram negative?

Answer 11

purple is gram positivie

Question 12

Name the type of haemolysis present on the blood agar below:

Answer 12

1. Beta hemolysis
2. Alpha hameolysis
3. Gamma haemeolysis

Question 13

What is the use of mannitol salt agar?

Answer 13

S.aureus- turns yellow

S.epidermis- stays red

Normally the agar is pink/red

Question 14

What species causes a psootive Dnase agar result with methyl green?

Answer 14

DNase hydrolysis - S.aureus

No DNAse hydrolysis= S.epidermis

Question 15

What is a postive result for bile aesculin agar, what bacteria will give a positive result?

Answer 15

Enterococci and group D streptococci

Question 16

What does MacConkey agar indicate, what is positive test result and what is a negative test result?

Answer 16

Lactose fermentors- have a pink-red colonies

Non-Lactose fermentors- these have as yellow like appearance/white

Question 17

What is a postive result for a catalase test?

Answer 17

gass production

Question 18

What is a positive result for a catalyse test?

Answer 18

coagulation of the the plasma

Question 19

What is a positive result for the DNase activity test?

Answer 19

distinct clear zone around growth

Question 20

What is a positive result for the indole test?

Answer 20

red colour in the re-agent layer

Question 21

What is a negative result for the indole test?

Answer 21

Yellow colour in the re-agent layer

Question 22

What is a positive result for the voges-proskaur effect?

Answer 22

a red colour

Question 23

What is a postive result for the methyl red test?

Answer 23

a strong red colour

Question 24

What is a positive result for citrate utilisation tests?

Answer 24

blue colour and visible growth

Question 25

Describe the appearance of the carbohydrate fermentation test if both acid and gas are produced:

Answer 25

yellow colour and gas in the Durham tube

Question 26

What is the appearance of a urease positive result?

Answer 26

pink

Question 27

Describe the possible results for a urease test and what they mean:

Answer 27

Motile organism = growth throughout the whole tube

Non-motile organism = growth along the stab line

H2S producing organisms = blakc growth and motile

Non-incubated tube = no growth in tube at all

Question 28

What is a positive result for lysine decarboxylase?

Answer 28

a purple/violet colour will be present.