Diagnosis of Viral Infections

Question 1

risk group 1

Answer 1

no or low individual and community risk

Question 2

risk group 2

Answer 2

moderate individual risk, low community risk

Question 3

risk group 3

Answer 3

high individual risk, low community risk

Question 4

risk group 4

Answer 4

high individual risk, high community risk

ex. Ebola

Question 5

BSL-4

Answer 5

maximum containment lab
lab workers should wear one-piece, positively air-pressurized, HEPA-filtered, supplied air suit
room should be negative air-pressured

Question 6

biohazard

Answer 6

biological substances that pose a threat to the health of living organisms, primarily that of humans

Question 7

biosafety

Answer 7

lab biosafety describes the containment principles, technologies and practices that are implemented to prevent the unintentional exposure to pathogens

Question 8

aerosol

Answer 8

very small droplets of fluid that can spread via air

Question 9

biosafety cabinets (BSC)

Answer 9

an enclosed, ventilated lab workspace for safety working with materials contaminated with pathogens requiring a defined biosafety level

Question 10

biosecurity

Answer 10

describes the protection, control and accountability for valuable biological materials in order to prevent their unauthorized access, loss, the misuse, diversion or intentional release

Question 11

have to make sure you collect samples at….

Answer 11

the right time
the right site
from the most appropriate animal

Question 12

chance of a viral recovery is best during the first _____ days

Answer 12

3

Question 13

viral recovery is greatly reduced after _____ days

Answer 13

5

Question 14

3 potential hazards associated with transport of pathogens

Answer 14

1- breakage of containers resulting in spillage
2- resulting in exposure to possible infection
3- a delay in package delivery to the diagnostic lab

Question 15

clinical signs of blue tongue in sheep

Answer 15

cyanosis of tongue, appears purple/blue

Question 16

turkey-egg shaped kidney….what disease

Answer 16

swine fever

Question 17

what virus has the presence of negri body inclusion factors?

Answer 17

rabies

Question 18

negative stain EM

Answer 18

virus is mixed with heavy metal salt solution, the mixture is then spread on a thin layer on a carbon-coated copper grid and dried…image is a negative image (see what is the background not the virus)

Question 19

TEM

Answer 19

based on transmitted electrons. seeks to see what is inside of beyond the surface. great resolution. 2D image

Question 20

SEM

Answer 20

based on scattered electrons. focuses on the surface and its composition. lacks resolution. 3D image.

Question 21

assay

Answer 21

qualitative or quantitative measurment of a target entity/analytic, such as a drug or biomolecule

Question 22

gold standard test

Answer 22

diagnostic test considered to be the most accurate and best available under a particular condition

Question 23

negative predictive value

Answer 23

the chance that a negative test result is actually negative

Question 24

positive predictive value

Answer 24

the chance that a positive test result is actually positive

Question 25

sensitivity

Answer 25

probability that cases with the infection will have a positive result using the test under evaluation

Question 26

specificity

Answer 26

probability that cases with the infection will have a negative result using the test under evaluation

Question 27

serum

Answer 27

clear-yellowish fluid obtained upon separating whole blood into its solid and liquid components after it has been allowed to clot. clot is removed

Question 28

plasma

Answer 28

produced when whole blood is collected in tubes that are treated with an anticoagulant

Question 29

direct ELISA

Answer 29

antigens are immobilized and enzymes-conjugated primary antibodies are used to detect or quantify antigen concentration. antibody attached directly to antigen

Question 30

indirect ELISA

Answer 30

primary antibodies are not labeled, but detect instead with enzyme-conjugated secondary antibodies that recognize the primary antibodies antibody attached to another antibody attached to the antigen

Question 31

sandwich ELISA

Answer 31

antigen to be measured is bound between a layer of capture antibodies and a layer of detection antibodies. the two antibodies must be very critically chosen to prevent cross-reactivity or competition of binding sites

Question 32

competitive ELISA

Answer 32

darker the sample =more negative | lighter the sample/no color= positive

Question 33

fluorescence antibody test (FAT)

Answer 33

antibodies are labeled with fluorescence which appears when attached to an antigen

Question 34

direct FAT

Answer 34

visible fluorescence appears at the binding site of the specific antibodies

Question 35

indirect FAT

Answer 35

marker recognizes the primary antibodies bound to antigen

Question 36

immunohistochemistry

Answer 36

antibody is tagged with enzyme, generally horseradish peroxidase. enzyme reacts with substrate to create a color change within infected cells

Question 37

direct assay

Answer 37

enzyme tagged with primary antibody that binds to antigen

Question 38

indirect assay

Answer 38

enzyme tagged to a secondary antibody that is specific against primary antibody

Question 39

immunochromatography/lateral flow devices

Answer 39

a form of point of care test that is simple to perform and does not require specialized equipment. sample is slid across a plate and if antibodies are present for the virus two bands will appear if not only the control line will be present

Question 40

agglutination

Answer 40

antibodies bind to many antigens into single clumps thereby forming large complexes which are easily precipitated.

Question 41

hemagglutination

Answer 41

virus + RBCs ---> mat formation

Question 42

hemagglutination inhibition

Answer 42

virus + RBCs + Ab ----> button formation

Question 43

complement fixation test

Answer 43

no hemolysis = antibodies present = positive reaction | hemolysis = no antibodies = negative reaction

Question 44

neutralization assay

Answer 44

loss of infectivity through reaction of the virus with specific antibodies