FeLV & FIV Flashcards
What type of virus are FeLV and FIV and what does this mean?
Retroviruses- they’re enveloped single stranded RNA
What are FeLV and FIV differential diagnosis’ for?
Immunosuppression- so if you suspect one you always test for both
What protein is the basis of many FeLV diagnostic tests?
Capsid protein p27- produced by the virus within infected cells [detected by diagnostic tests]
What is the role of the surface glycoprotein on the FeLV virus?
Defines the subgroup and is the target for vaccination
What is the role of the P15E transmembrane protein on FeLV viruses?
causes immunosuppression in the host
Once FeLV has integrated into the host DNA within a cell, what 3 mechanisms can occur?
- destruction of virus infected cell by the immune response
- infection with/ without virus production
- transformation to tumour cell
What do we mean by a regressor cat/ abortive infection?
Infected with FeLV initially but has effectively eliminated the virus and gained lifelong immunity
What do we mean by regressive infected FeLV cat?
they carry FeLV DNA in their bone marrow- at this point they’re not infective for other cats BUT the virus may be reactivated at some point at which point they may begin to show clinical signs and become a source of infection for other cats
What is a focal/ atypical infection of FeLV?
when the cat’s immune system keeps virus replication sequestered to certain tissues- will test negative if not sampled from these tissues
What are the four types of FeLV pathogenesis infections and do these cats test positive or negative for FeLV?
Abortive- test negative
Regressive- test positive (but not infectious mostly)
Focal/ Atypical- test negative unless taken from specific tissues
Progressive- test positive
Where does FeLV replicate?
Replicates in the local lymphoid tissues before systemic spread to bone marrow
Where does FeLV populate?
populates salivary glands and mucosal glandular epithelium (hence why it spread via saliva and nasal secretions)
What are the signs of FeLV in a progressively infected cat?
Immunosuppression- lots of secondary infections
Neoplasia (mainly lymphoma)
Bone marrow disorders
When do bone marrow disorders as a result of FeLV develop?
when the virus infects haematopoietic stem cells and stromal cells
What 5 diagnostic tests can we do to diagnose FeLV?
ELISA detection of P27
Immunofluorescence for antigen inside infected cells
PCR for FeLV RNA
Viral Culture
Testing for neutralizing antibody
What is the first line option for diagnosis of FeLV?
ELISA detection of P27 antigen using serum (some false positives associated with plasma/whole blood)
When can we test kittens with an ELISA detection of P27?
Anytime- because we’re testing antigen presence
After we have used the first line diagnostic test for FeLV (ELISA) what do we do next?
Confirmatory tests (the other 4 available)
What is good about PCR for FeLV RNA?
Can confirm if the infection is progressive or regressive
What is the prognosis of cats with FeLV?
Good if no lymphoma development- approx 2.5 years
How can we prevent FeLV infection?
only introduce negative cats into the household- consider keeping them indoors unless they’re vaccinated
Is there an FeLV vaccine available in the UK? Is it always used?
Yes- 5 types licensed but only used based on risk of exposure as it can cause injection site sarcomas
When can we test kittens for FeLV?
at 6 weeks of age- but good practice to do 2 tests
What cells does FIV infect?
CD4+ T cells, B cells and activated macrophages
What is unique about the envelope of FIV?
It’s derived from the host cell
Which groups are most at risk of FIV?
male, aggressive, free roaming cats
What are the most common clinical findings in a cat with FIV? (5)
Gingivostomatitis
Neoplasia
Ocular signs such as Uveitis
Anaemia
Chronic Kidney disease
When is an FIV test indicated? (5)
Sick cats- particularly those with anaemia, or those infected with mycoplasma
Cats that are being rehomed
Kittens from FIV+ queens
Cats with bite wounds
Cats living with an FIV+ cat
What is the first line test used for FIV diagnosis? What is the confirmatory test?
1st line- ELISA of FIV antibody
Confirmatory- Western blot or Immunofluorescence assay
If a cat has previously lived abroad and its medical history unknown- can we use an ELISA to test for FIV?
What’s the alternative?
Not really- UK doesn’t vaccinate for FIV but other countries do and ELISA doesn’t differentiate between vaccinated and infected- only a PCR of FIV RNA can differentiate
A positive FIV serology result (ELISA) means… (2)
- Cat is infected with FIV
- Cat has circulating maternal antibodies- need to retest older than 6 months old
A negative FIV serology result (ELISA) means… (3)
- Cat is not infected
- Cat is infected but hasn’t generated an immune response yet- retest in 60 days
- Disease is terminal and antibody production has fallen due to immunosuppression
Does an FIV positive diagnosis affect survival time?
NO
How do we treat a systemically sick FIV cat?
bacterial antibiotics
possibly use glucocorticoids
When do we test kittens who have come from an FIV+ queen?
Can test at 16 weeks and then retest 6 weeks later but vertical transmission unlikely
