Infectious Disease Flashcards
a 3yo DSH presents for acute anorexia, she is febrile, and has lost weight. differential?
you can see a mediastinal mass (dorsal deviation of the trachea, increased opacity), and large mediastinal LNs. top differential is FeLV associated lymphoma
what is FeLV?
feline leukemia virus
a gamma retrovirus, a single RNA strand with protein core. for testing, p27 is what you are testing for
how is FeLV transmitted? how does this differ from FIV?
felv you give to your friends: through saliva, licking, grooming, etc
FIV you give to your enemies: is transmitted thru blood, cat fights
what percent of cats have an effective immune response when they first get FeLV?
40% of cats can “handle it” and have an appropriate immune response and are a healthy cat. the other 60% have an “ineffective” immune response
of the cats whose immune response is “ineffective” what happens to them?
the virus will be transient for 6-8 weeks, which can eventually lead to viremia where the virus is everywhere. from viremia the virus can:
1. become a healthy carrier
2. become a regressive infection where the virus goes to sleep
3. become a progressive infection with high shedding and clinical disease
if the virus becomes regressive it can reactivate during times of stress of immunosuppression and become progressive
an acute infection of FeLV may result in one of 3 courses:
- an effective immune response eliminates the virus, ABORTIVE cat, negative on all tests, life long protection
- virus sequestered in regressive form, REGRESSIVE infection, no shedding, low disease incidence, only positive on PCR
- progressive infection, persistent viremia, positive on all tests
transient viremia in FeLV can last _____
6-8 weeks
this is why we retest after 8 weeks
in the progressive state of FeLV, the virus is in the
bone marrow
what are the 5 “things” FeLV can cause?
infections, anemias, lymphoma, leukpenia, leukemia
what are the clinical signs of FeLV?
weight loss and fever most commonly
others: conjunctivitis, rhinitis, diarrhea, enlarged LNs, stomatitis
you decide to run a CBC on a cat you suspect has FeLV. what do you expect to see?
a regenerative anemia: IMHA, mycoplasma, blood loss from low platelets
lympopenia, neutropenia
if non regenerative anemia: the virus could be in the bone marrow, myelosuppression, chronic inflammatory disease
platelet abnormalities
what immune mediated diseases can result from FeLV?
IMHA
IMT
IMPA
uveitis
glomerulonephritis
how does FeLV cause neoplasia?
the FeLV genome is inserted into the genome near the oncogene (cancer causing gene). results in lymphoma usually, either mediastinal/thymic or multicentric
you should test for FeLV on any cat that:
is sick
before adoption
exposed to FeLV or FIV
outdoor urban cats
cats with unknown FeLV status
cats living with positive cats
what are the 3 tests you can do for FeLV?
ELISA antigen test (SNAP test): serum or plasma, testing for p27
IFA: super rare, a send out test, test for cell associated P27 antigen
PCR: most places don’t do this test, tests for viral RNA or proviral DNA
true or false: maternal antibodies interfere with the FeLV test
false
how should you interpret a + or - FeLV snap test?
negative: re test if the cat is less than 12 weeks old or if it’s been less than 30 days since an exposure
positive: re test in 6-8 weeks in case they clear the virus, if they’re positive on this test, then they did not clear it and they have it
IFA test for FeLV detects:
p27 gag protein in WBC or platelets released from the bone marrow after virus replication