Retroviridae Flashcards

(51 cards)

1
Q

How do retroviruses convert +ssRNA to complementary DNA (cDNA)?

A

RNA-dependent DNA polymerase

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2
Q

What are the unique features about replication of retroviruses?

A
  1. Diploid RNA
  2. RNA dependent DNA polymerase
  3. Many steps in the replication process cause a slow progression or chronic infection.
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3
Q

Are retroviral genomes infectious?

A

NO

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4
Q

What is the genome of retroviruses?

A

+ssRNA

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5
Q

Are retroviruses enveloped or non-enveloped?

A

Enveloped

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6
Q

What are three possible types of retrovirus genomes that can exist in a single infected cell?

A
  1. +ssRNA
  2. linear dsDNA
  3. integrated dsDNA
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7
Q

What type of infection is associated with V-onc+ retrovirus infection?

a. Immune compromising infection
b. Latent infection
c. Acute infection
d. Acute transformation or tumor

A

D.

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8
Q

What are the major steps in retroviral genome replication?

a. ssRNA to dsDNA
b. ssRNA-cDNA-dsDNA
c. ssRNA-cDNA-dsDNA-chromosome integration-mRNA or ssRNA
d. +ssRNA to –ssRNA to +ssRNA

A

C.

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9
Q

Which gene is used to differentiate FeLV from FIV (two different groups)?

a. Gag gene
b. Pol gene
c. Env gene
d. None of the above

A

A.

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10
Q

Which gene is used for FeLV subgroup classification?

a. Gag gene
b. Pol gene
c. Env gene
d. None of the above

A

C.

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11
Q

What is the proper material for FeLV antigen detection?

a. Leukocytes
b. Plasma
c. Serum
d. Saliva
e. These are all appropriate samples; but most often you are using whole blood or plasma

A

B.

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12
Q

What is the difference between FeSV and FeLV?

a. Replication in different tissues
b. Have different morphology
c. Have different genome types
d. One is onc+ and one is onc

A

D.
FeLV: Onc+
FeSV: Onc-

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13
Q

Are all retroviruses oncogenic?

A

NO

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14
Q

Is the gp70 an envelope protei?

A

YES

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15
Q

Where is the p27 in the virion?

A

Capsid

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16
Q

Which gene is encodes for gp70?

A

Env genes

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17
Q

Which gene is encodes for gp27?

A

Gag genes

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18
Q

What FIV antibody is detected in the FeLV/FIV test (Idexx snap test)?

A

gp120

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19
Q

What FeLV antigen is detected in FeLV/FIV test?

A

p27

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20
Q

How many types of FeLV subgroups are there and what is different about them?

A

Subgroups are based on differences in the env gene. There is an A (immunosuppression)
, B(neoplastic disease) , and C subgroup (severe anemia) .

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21
Q

Which subgroup of FeLV is found in all cats infected with the virus?

22
Q

What type of virus is FeLV?

A

It is a Onc- retrovirus.

23
Q

If a cat with FeLV has a good immune response, what will be see diagnostically?

A

A neutralizing antibody titer will show high anti-gp70. The p27 antibodies not detectable and there is a low anti FOCMA titer because viral proteins not actively being made in host.

24
Q

What is Feline Oncovirus Membrane associated antigen (FOCMA)?

A

A nonstructural protein expressed on the surface of infected cells that induces an antibody response from the host. It is protective against FeLV-induced neoplasm.

25
Where the consequences of viremia with FeLV?
1. Cytoproliferative effects ( fibrosarcomas, leukemias, lymphosarcomas) 2. Cytosuppressive effects ( pancytopenia, anemia, immunosuppresions)
26
What are the clinical features of an FeLV infection ("fading kitten syndrome ) ?
1. Immunosuppression 2. Lymphoid/myeloid tumors 3. Anemia 4. Immune complex diseases 5. Reproductive problems
27
If a cat with FeLV does have an immune response, what will be seen diagnostically? What about a limited immune response?
VN titer: Gs antigen detectable and anti-FOCMA titer not detectable; Vn titres: Both Gs and FOCMA antibody detectable
28
What is an important side effect of the FeLV vaccination?
Injection site sarcoma, most likely caused by the adjuvant
29
How would be diagnose FeLV in the clinic?
1. Antigen detection tests like IFA and ELISA that detect p27. The best sample is serum, but whole blood, plasma, saliva and tears can also be used. 2. VN antibody detection that detects antibodies to gp70.
30
How can we prevent FelV?
Inactivated virus or subunit vaccine
31
What is feline sarcoma virus (FeSV)?
A recombinant of FeLV, a Onc+ version of FeLV.
32
What tropism does feline sarcoma virus have?
Immune cells like WBC stem cell and thrombocytes
33
How is FeSV transmitted?
Horizontal via urine, feces, and milk. | Vertical via transplacental
34
Do tumors only occur in cats persistently infected with FeLV?
YES, due to poor immune responses.
35
As a whole, what do oncogenic retroviruses do to the body?
``` Lymphomas Hemangiomas Reticuloendotheliosis Lymphosarcoma Malignant lymphoma Retinoblastoma ```
36
Compared to FeLV, what genes in FIV are different?
1. Env | 2. gag
37
FIV pathogenesis...GO
Bite (saliva)-infects lymphocytes and macrophages- B-cell proliferation-reversed CD4: CD8 ratios-immunodeficiency leading to opportunistic infections and B-cell lymphomas.
38
What are the clinical signs of a FIV infection?
1. Gingivitis/periodontitis 2. URI (respiratory infection) 3. Diarrhea 4. Pyoderma/rough coat 5. Altered behavior
39
How is FIV diagnosed?
1. Detection of antigen via IFA for p24 or p17 (ELISA not practical as low levels of circulating antigens) 2. Detection of antibodies via ELISA for gp120 and gp41, or a more sensitive western blot.
40
What is the cell tropism for Caprine arthritis-encephalomyelitis (CAE)?
Lymphoid tissue and macrophages
41
How is CAE transmitted?
Horizontal only
42
What are the forms of CAE?
1. Arthritic 2. Encephalitic 3. Pneumonic 4. Mastitic 5. Chronic wasting
43
What is the clinical signs of a CAE infection?
In kids: neurological disease with progressive leuko encephalomyelitis In adults: arthritis and mastitis
44
How is CAE diagnosed? | Is there a vaccine?
ELISA | NO
45
T/F After a horse becomes infected with equine infectious anemia virus, that horse is always a reservoir.
True
46
How is EIA transmitted
1. In utero 2. Contaminated instruments 3. Biting insects
47
What are the forms of EIA?
1. Acute/chronic: Fever, depression, and small hemorrhages 2. Per-acute (rare): Same as acute, but add anemia, icterus, rapid breath, edema, weight loss, colic, and abortion. 3. Chronic/asymptomatic carriers: No signs, unless stressed
48
How is EIA diagnosed?
1. Coggins 2. ELISA 3. Horse inoculation 4. Immunoblot
49
What can lentivirus infections cause in animals?
1. Encephalitis 2. Anemia 3. Pancytopenia 4. Lymphopenia 5. Abnormal lymphocyte profiles
50
Which lentiviruses have we discussed in this class?
1. Equine infectious Anemia virus 2. Caprine arthritis- encephalomyelitis 3. Visna/Maedi Virus 4. Feline Immunodeficiency Virus
51
Which oncogenic retroviruses have we discussed in this class?
1. Feline Leukemia (FeLV) 2. Feline Sarcoma virus (FESV) 3. Bovine Leukemia