Feline Retroviruses

Question 1

What age of cat is most susceptible to FeLV?

Answer 1

(Young kittens, adults develop a natural immunity; other risk factors include high population density and being an outdoor cat)

Question 2

(T/F) FeLV can be transmitted both horizontally and vertically.

Answer 2

(T, high viral doses in saliva, nasal secretions, milk, urine, and feces and can be passed in utero)

Question 3

FeLV replicates in the local lymphoid tissues of oropharynx (bc infection typically acquired through oronasal exposure) and infects monocytes and lymphocytes which induces a low level primary viremia, where does viral replication then migrate to and what is produced?

Answer 3

(Viral replication occurs in the bone marrow during the primary viremia stage and the FeLV-containing leukocytes and platelets are produced inducing a secondary viremia → this is what is detected by IFA 30 days post exposure)

Question 4

What are the three possible outcomes of an FeLV infection?

Answer 4

(Progressive infection, regressive infection, and abortive infection)

Question 5

Which type of FeLV infection is thought to have a high risk of clinical disease due to FeLV?

Answer 5

(Progressive)

Question 6

Which of the types of FeLV infection will trigger a positive result on an IFA?

Answer 6

(Progressive infections)

Question 7

(T/F) Once past the initial viremia (~16 weeks post exposure) associated with regressive FeLV infections, the cat should test negative on POC tests.

Answer 7

(T, they may be positive on a PCR but low numbers; IFA will be negative)

Question 8

(T/F) A cat with an abortive FeLV infection will test negative on a POC ELISA, PCR, and IFA.

Answer 8

(T)

Question 9

Describe the anemia that would indicate to you that FeLV is inducing the anemia in a sick cat.

Answer 9

(Severe, nonregenerative anemia with macrocytosis)

Question 10

How is FIV primarily transmitted?

Answer 10

(Bite wounds, this means primary risk factors are being male and living outdoors)

Question 11

What are the most common types of neoplasia that form in progressively infected FeLV cats?

Answer 11

(Lymphoma and leukemia)

Question 12

What does the POC ELISA detect to test for FeLV infections?

Answer 12

(p27 antigen)

Question 13

The FeLV/FIV snap test will be positive for FeLV in an exposed cat within how many weeks of infection?

Answer 13

(4)

Question 14

You are presented with a healthy cat that tests positive for FeLV on a POC ELISA test, what do you want to do next and how will that change your further steps?

Answer 14

(Rerun the test, if still positive, consider IFA (if other cats in household) or retesting in 16 weeks (if no other cats to worry about passing FeLV to) , if negative could indicate no exposure or too recent of an exposure, can retest in 30 days if truly a worry or monitor)

Question 15

What can cause a POC ELISA to be positive but the follow up IFA to be negative?

Answer 15

(If the infection is regressive, the IFA was performed too early (before bone marrow infection), if there is a low level cell associated viremia (such as if there is a cytopenia, there won’t be enough cells with FeLV antigen in them to trigger a positive IFA), and a false positive ELISA (but this is rare))

Question 16

What can cause a positive FIV POC ELISA test?

Answer 16

(The cat has FIV, the cat has been vaccinated for FIV, it is false positive, or if tested in a cat less than 6 months of age = material antibodies)

Question 17

How long does it take for a cat to seroconvert after being infected with FIV (i.e. they will test negative on a POC ELISA until this point)?

Answer 17

(60 days, can take 8 weeks to 6 months but 60 days is the generally followed rule)

Question 18

You tested a cat you suspect has FIV because they are immunosuppressed with an normocytic, normochromic, non-regenerative anemia that had a history of being an outdoor cat previously, they came up negative, what do you want to do next?

Answer 18

(Consider running a Western Blot (confirmatory FIV test) or retest in 60 days (honestly in this case just run a western blot, I’m trying to imply the cat should definitely be exposed and seroconverted by now but if it was a recent exposure (male cat got outside and came back with a bite wound abscess or something, retesting in 60 days is more appropriate))