Retroviridae - Lentiviruses: Feline Immunodeficiency Disease

Question 1

What is the cause of feline immunodeficiency disease?

Answer 1

Feline lentivirus (FIV)

Question 2

How many subtypes of FIV are there and what are they base on?

Answer 2

5 subtypes (A-E) based on variations on the env gene

Question 3

Which subtypes of FIV predominate in North America?

Answer 3

Subtypes A and B

Question 4

True/False. There is no cross-presentation between subtypes.

Answer 4

True

Question 5

What is the principal mode of transmission of FIV?

Answer 5

Cat bites

Virus is mainly shed in saliva

Infection is lifelong

[in-utero transmission and transmission via colostrum or milk has also been documented]

Question 6

What is the hallmark pathogensis of FIV?

Answer 6

Disruption of immune function

There is a progressive loss of CD4 helper T-lymphocytes in the early stages and a loss of CD8 T-lymphocytes as well in the later stages

Question 7

What are the causes of CD4 cell loss?

Answer 7

1. Decreased production secondary to bone marrow or thymic infection
2. Cytopathic effect of FIV
3. CTL mediated cytolysis of cells
4. Death by apoptosis

Question 8

Which phase of FIV infection are cats either asymptomatic or may show transiently clincial signs of fever, malaise, lymphadenopathy, or diarrhea?

Answer 8

Acute phase

[antibodies against virus detected, but ineffective in eliminating virus]

Question 9

Which phase of FIV infection will cats show clinical signs of persistant lymphadenomegaly?

Answer 9

Latent phase

Follows acute phase, prolonged latency period of variable duration that may persist for years before signs of immunodeficiency occur

Question 10

Which phase of FIV infection shows clincal signs of an acquired immunodeficiency syndrome that predisposes to chronic recurrent opportunistic infections?

Answer 10

Terminal phase

Opportunistic infections caused by bacteria and fungi, such as chronic stomatitis and givingivitis, chronic respiratory disease, chronic diarrhea and wasting, dermatitis, neurological sings, etc.

Question 11

Which FIV antigen is detected by a SNAP test?

Answer 11

p24 core antigen

Question 12

Is FIV zoonotic?

Answer 12

No, there is no evidence.

Although FIV is a lentivirus similar to HIV and causes a disease in cats similar to AIDS, FIV is a highly species-specific virus that infects only felines.