Prions and Tumor Viruses

Question 1

What are prions?

Answer 1

infectious proteinaceous particles without nucleic acid

Question 2

What is the incubation period associated with prions?

Answer 2

long

Question 3

What are the neuropathological changes associated with prions?

Answer 3

vacuolation of neurons

Question 4

Prions are abnormal ________ of normal _________

Answer 4

folding
glycoprotein

Question 5

What is the native protein of a prion and what is its structure

Answer 5

PrPc
a-helical structure

Question 6

What cells are prions present in?

Answer 6

normal cells including lymphocytes and neurons

Question 7

When PrPc interacts with PrPsc what is its conformation?

Answer 7

B-sheet

Question 8

PrPsc accumulates where? What does this accumulation lead to?

Answer 8

neurons
leads to vacuolation and development of neurologic signs

Question 9

What are the 3 ways in which transmissible spongiform encephalopathy can arise?

Answer 9

Transmissible in external sources
sporadic conversion
familial mutation

Question 10

What is scrapie and what species does it affect?

Answer 10

fatal neurologic disease of adult sheep and goats

Question 11

Why is scrapie usually seen in breeding aged sheep?

Answer 11

due to long incubation period

Question 12

What are the typical clinical signs of scrapie?

Answer 12

restlessness/nervousness
pruritis leading to loss of wool
emaciation
death within 6 months

Question 13

What would you see histologically in a scrapie case?

Answer 13

no inflammation only vacuolation of neurons

Question 14

True or false: Bovine spongiform encephalopathy (BSE) is not considered species specific

Answer 14

TRUE

Question 15

What was the BSE epidemic attributed to?

Answer 15

feeding meat and bone meal of sheep to cattle

Question 16

What led to a decline in BSE? What are the control measures in the US?

Answer 16

banning of ruminant-derived meat and bone meal
control measures include incarceration of small ruminant carcasses and brains and spinal cords of cattle older than 30 months

Question 17

What are the clinical signs of BSE?

Answer 17

ataxia, hypermetria, tendency to fall

Question 18

Is there horizontal transmission of BSE?

Answer 18

NO

Question 19

What is chronic wasting disease (CWD)

Answer 19

TSE of elk, mule, deer, and moose

Question 20

What are clinical signs of CWD?

Answer 20

chronic weight loss, behavioral changes, ataxia, tremors

Question 21

What is the transmission of CWD thought to be caused by?

Answer 21

contamination of grass or in utero

Question 22

What is BSE thought to have developed from?

Answer 22

Sheep scrapie

Question 23

Which TSE variant can infect humans? Which cannot?

Answer 23

BSE can infect humans but sheep and deer variants cannot

Question 24

Which TSE can be transmitted via infected pasture?

Answer 24

scrapie and CWD

Question 25

What is BSE transmitted by?

Answer 25

ingesting brains and spinal cords

Question 26

What do retroviruses contain?

Answer 26

reverse transcriptase

Question 27

Are retroviruses labile or stable? RNA or DNA? enveloped or non-enveloped?

Answer 27

Labile, enveloped RNA viruses

Question 28

What is the dsDNA of retroviruses integrated as in the host?

Answer 28

provirus

Question 29

What is the insertion of a retrovirus determined by?

Answer 29

random - chance

Question 30

Retroviruses can be endogenous or exogenous. Explain the difference

Answer 30

endogenous is widespread, can constitute 10% of genome, transmitted by vertical transmission, and usually silent but can recombine with exogenous retroviruses exogenous can be horizontal transmission

Question 31

What do oncogenic retroviruses induce in the cells they infect?

Answer 31

neoplastic transformation

Question 32

What type of retrovirus is Feline Leukemia Virus

Answer 32

gamma retrovirus

Question 33

What do most clinical FeLV infections manifest as?

Answer 33

anemia or immunosuppression

Question 34

What are the subgroups of FeLV?

Answer 34

A, B, C, T

Question 35

What subgroup of FeLV do all positive cats have? How would they acquire the others?

Answer 35

ALL HAVE A can have others through mutation

Question 36

What do cats infected with FeLV A and B have a higher risk of?

Answer 36

developing tumors

Question 37

What does FeLV A and C result in?

Answer 37

fatal anemia

Question 38

What is FeLV T associated with?

Answer 38

T-cell tropic --> immune deficiency

Question 39

What cats are more at risk or more likely to be infected with FeLV?

Answer 39

domestic outdoor purebred multi-cat household Young cats

Question 40

What are common ways of transmission of FeLV?

Answer 40

direct contact with saliva fleas iatrogenic vertical transmission nursing, milk

Question 41

What are the virus target cells of FeLV?

Answer 41

mitotically active cells

Question 42

FeLV infected cells are more likely to develop _______ or _________ with ________ being the most common

Answer 42

leukemia or lymphoma lymphoma is most common

Question 43

What is enzootic bovine leukosis?

Answer 43

retroviral disease of adult cattle

Question 44

What is enzootic bovine leukosis characterized by?

Answer 44

persistent lymphocytosis and B-cell lymphoma

Question 45

What is enzootic bovine leukosis transmitted by?

Answer 45

blood or secretions, milk, iatrogenic

Question 46

What is the primary target cell of enzootic bovine leukosis?

Answer 46

B lyymphocyte

Question 47

What is the infection time of enzootic bovine leukosis?

Answer 47

lifelong with most sub-clinically infected

Question 48

What are common sites of enzootic bovine leukosis?

Answer 48

lymph nodes, heart, GIT (abomasum), liver, spleen, uterus, kidney

Question 49

If you saw a lymphoma in a calve or a thymic lymphoma what would you say its relation is to BLV?

Answer 49

no association

Question 50

Which retrovirus is associated with T cell lymphoma? B cell lymphoma?

Answer 50

FeLV BLV