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
proper way to care for a healthy cat testing positive for FeLV?
keep indoors only, neuter them, have a PE and CBC/chem at least twice a year, perioperative antibiotics with any surgery, avoid raw diets, if vaccinating, use core killed vaccines
proper way to care for a sick cat testing positive for FeLV?
blood transfusions, erythropoietin, filgrastim, chemotherapy
what treatment options are there for FeLV cats?
Zidovudine (AZT): very expensive, blocks retroviral reverse transcriptase
feline interferon-omega: stimulates the immune system
true or false: the FeLV vaccine does not prevent transient viremia
true! vaccination will not cause a positive test result, the test is testing for the antigen
what is the prognosis for FeLV?
death rate for persistwntly viremic cats in multi cat households: 50% in 2 years, 80% in 3 years.
max, a 6yo DSH presents with severe halitosis, hypersalivation. upon PE you see severe stomatitis. differential?
test for FIV
what is FIV?
lentivirus with 5 main subtypes, A and B most common
virus hangs out in salivary epithelium, salivia, in lymphocytes, plasma, and serum
how does FIV cause disease (aka what does it do)?
the virus infects B cells, T cells, and macrophages, spreading to lymphoid organs and causing viremia and a continuous low level of viral replication. overall this leads to immune suppression, opportunistic infections, neoplasia, etc
true or false: younger animals develop clinical signs faster at the time of infection with FIV compared to older cats
true
the hallmark of FIV pathogenesis is
progressive disruption of normal immune function
what other organ besides lymph tissue can be involved in FIV?
neurologic tissue
the FIV test is testing for
antibodies
clinical signs of FIV?
fever, enlarged LNs, stomatitis/gingivitis
azotemia is associated with…
FIV associated CKD
maternal antibodies interfere with which test: FeLV or FIV?
FIV!
how to interpret a + and - FIV test
negative: not infected, but if has been exposed, retest minimum 60 days later
positive: if the cat is less than 6 months old it is likely maternal antibodies, if he cat is oldr than 6 months, it is likely FIV
which organs does FIV like?
all of them…!!!
which neoplasia does FIV cause most of the time?
lymphoma
what are some treatment options for FIV?
extraction of all teeth, keep them indoors, regular PEs, vaccinate for all other diseases (no FIV vaccine available), keep healthy cats away from infected cats
which has a better survival, FeLV or FIV?
FIV
Han, a 2yo DSH presents in acute resp distress, increased resp effort, nasal flaring. on POCUS you see free fluid in the abdomen. top differential?
FIP
what is FIP?
immune mediated disease caused by mutation of Feline Coronavirus, cats carry this virus for life and it normally causes very mild disease
once feline coronavirus mutates to FIP, what are the 3 outcomes?
- the body can clear it via cell mediated response (not common)
- granulomatous lesions form with immune complexes (dry form)
- vasculitis, effusion in pleural and abdominal spaces (wet form)
clinical signs of FIP?
fever, uveitis, dyspnea, tachyonea, muffled heart sounds, weight loss, anorexia, icterus, big LNs, neurologic signs, irregular organs
how can you diagnose FIP?
it is difficult
hyperglobulinemia,hyperglobulinemia, hyperbilirubinemia, effusion or granulomas on rads
effusion analysis: high protein count, lower cellularity, pyogranulomatous effusion (very thick fluid like egg yolks). can also do RT-PCR on the fluid only for the wet form
is fecal coronavirus antibody test good for diagnosing FIP?
no because it doesn’t tell you if it’s mutated, and almost all cats have feline coronavirus…
what options are there for FIP treatment?
historically poor prognosis, death in days
now: GS-441524 and Remdesivir, oral or injection or both, currently you cannot get it legally in Canada but you can tell owners it exists
any ways to prevent FIP?
difficult bc most cats get feline coronavirus
wait 3 months before adoption if you had a previous FIP cat
