cat infectious disease Flashcards
What is Feline Leukemia Virus (FeLV)? what is transmission?
gamma retrovirus
primarily saliva, through social behaviours (allogrooming)
also vertical transmission
cats give ___ to their friends (allogrooming) and ____ to their enemies (blood).
FeLV, FIV
what signalments are common with FeLV? i.e When should we be worried about FeLV?
- kittens <4mo
- negative cats w/ infected cats (new cats at home)
- abscesses/bite wounds
- males
- outdoor cats
tell me about the epidemiology and pathogenesis of FeLV. like what happens to the cat once they get an infection?
FeLV exposure –> either effective immune response or ineffective immune response
effective immune response = abortive cat –> negative on all tests, lifelong protection to FeLV = healthy cat
ineffective immune response = transient viremia (infectious + shedding)–> either viremia or abortive cat
viremia either goes to healthy carrier, progressive infection, or regressive infection
progressive infection = high shedding, high incidence of disease (positive on all tests)
healthy carrier = low shedding
regressive infection = no shedding, low incidence of disease (negative on ELISA and IFA, positive proviral PCR)
regressive infection either leads to progressive infection through stress or immunosuppression, or an abortive cat through complete viral elimination
true or false: up to 70% of cats with FeLV exposure can clear virus even if they test positive initially
true
how long does the transient viremia last in FeLV? why is this important?
6-8 weeks
we retest cat after 8 weeks because they may be positive after 8 weeks even if they were negative at first
which tests are positive/negative with regressive state FeLV?
ELISA and IFA negative, proviral PCR positive
what is the difference between FeLV regressive and progressive states?
regressive: rarely develop FeLV-assoc disease, usually no bone marrow involvement, not shedding, not infectious, FeLV proviral DNA integrated into cat’s genome, can revert to progressive state with stress (less likely as time goes on), ELISA and IFA negative, proviral PCR positive
progressive: often develop FeLV-assoc disease, virus in bone marrow and multiple organs, shedding and infections, all tests positive
what are the lesions of FeLV?
- infections
- anemia
- lymphoma
- leukopenia/thrombocytopenia
- leukemia/MPD
what are the C/S of FeLV?
weight loss, fever, conjunctivitis, rhinitis, diarrhea, lymphadenopathy, stomatitis, asymptomatic
basically, if they have symptoms, they ADR
can get secondary infections/immune-mediated diseases
what are the changes on hematology with FeLV?
- regenerative or non-regenerative anemia (secondary to bone marrow suppression)
- neutropenia and lymphopenia
- thrombocytopenia or thrombocytosis
- pancytopenia
if you have a cat with an immune-mediated disease, what should you do?
test for retrovirus (FeLV)
why do cats with FeLV get neoplasia? what is the most common neoplasia?
lymphoma
insertion of FeLV genome near cellular oncogene
when should you test for FeLV and FIV?
- any sick cat
- prior to adoption
- cats recently exposed to FeLV/FIV
- outdoor urban cats
- cats with unknown FeLV status
- cats living with positive cats
you have a sick cat and you decide to test for FeLV. tell me what you do and what you will do depending on test outcomes
ELISA antigen testing (snap test)
if negative: retest if <12 weeks old or if <30 days exposure
if positive: retest in 6-8 weeks in case they clear virus
we rarely use IFA anymore. instead just redo ELISA
true or false: maternal antibodies interfere with FeLV testing
false! they do NOT interfere!
what does the FeLV ELISA snap test measure?
free soluble p27 gag protein in plasma, serum, whole blood, saliva, tears
usually positive within 30 days of viral exposure
tell me about the sensitivity and specificity of ELISA FeLV snap test
lower sensitivity (63-100%), high specificity (94-100%)
what do we need to know about the IFA FeLV test?
if IFA +, means there is virus in bone marrow. very specific, not that sensitive. don’t use as screening test.
tell me the FeLV test results for these examples:
1. FeLV exposure with effective immune response (abortive cat)
2. transient viremia following FeLV exposure
3. regressive FeLV infection
4. viremia following FeLV exposure
5. progressive FeLV infection
6. healthy carrier
- negative on all tests
- positive ELISA, positive PCR
- negatie ELISA, negative IFA, positive PCR
- positive ELISA, positive PCR
- positive ELISA, positive IFA, positive PCR
- positive ELISA, positive IFA, positive PCR
how should you care for healthy FeLV+ cats?
- keep indoors
- neuter
- PE and CBC at least twice yearly
- preoperative Abx surgeries/dentals
- avoid raw diets
- vax with core killed vaccines
how should you care for sick FeLV+ cats?
- treat concurrent diseases
- blood transfusions
- erythropoietin, darbapoietin (stimulate BM RBC prod)
- Filgrastim (help with neutropenia)
- chemo (with confirmed lymphoma)
- (euthanize)
what are the treatments for FeLV?
- Zidovudine –> blocked retroviral reverse transcriptase (human HIV drug, expensive)
- feline interferon-omega: potentially effective when secondary infections, but difficult to get in NAm
should you FeLV test before or after the vaccine?
before
who should you vaccinate against FeLV?
at risk cats (multicat environments with FeLV+ housemates, free-roaming young cats, urban outdoor cats)
true or false: FeLV vaccine prevents transient viremia
false!
it’s like the flu vax - you’ll get FeLV but not a bad case
true or false: vaccination against FeLV will cause a positive test result
false!
what is Feline Immunodeficiency Virus (FIV)? what is transmission?
Lentivirus
virus in salivary epithelium, saliva, lymphocytes, plasma, serum
primarily via bite/fight wounds
vertical transmission possible
tell me about the pathogenesis of FIV. like what happens to the cat once they get an infection?
what is the hallmark of FIV pathogenesis?
progressive disruption of normal immune function
does age of the cat have any bearing on FIV disease progression?
yes! younger animals develop C/S faster
what are the C/S of FIV?
so many lmao
fever, lymphadenopathy, neuro signs, uveitis/conjunctivitis, dermatitis, stomatitis, gingivitis, abscesses, URI, weight loss/emaciation, diarrhea, CKD, neoplasia
how do you diagnose FIV?
CBC:
- neutropenia
- lymphopenia
- anemia
- thrombocytopenia
chem:
- azotemia
- hyperglobulinemia
ELISA snap test (serum)
Western blot
IFA
PCR
true or false: maternal antibodies do not interfere with FIV testing
false. they DO interfere!!!
you test a cat for FIV. tell me what each result means (+ vs -) and what you will do with each
negative = not infected
positive = consider age
<6mo –> likely maternal Ab, retest >6mo
> 6mo –> Western blot or PCR
+ western blot or PCR = infected
- western blot or PCR = retest in 60 days
what should you do if a recently FIV exposed cat tests negative using ELISA?
test again a min of 60 days after exposure to allow time for seroconversion
true or false: you get increased risk of neoplasia with FIV.
true. less than FeLV, but more than normal cats
what type of neoplasia are FIV positive cats most susceptible to?
lymphoma
true or false: FIV vaccine is available in NAm
false. it is not :(
what treatments are available for FIV?
- antivirals (AZT = too expensive)
- complete dental extractions if stomatitis
- human interferon alpha or omega (but not available)
how do you manage a FIV+ cat (hint: they can live for years!)
- indoors
- regular PEs
- vaccinate for other infectious disease
- isolate infected cats from healthy cats
tell me the pathogenesis of FIP
you already know this from research :)
FCoV (FECV) = infectious, lots o cats have this, replicates in enterocytes
FECV mutates to FIPV = mutates in macrophages, goes into da body
this next bit is according to the lecture…. in reality, wet vs dry is not useful as it is a spectrum and any cat can present with any lesions*
FIP mutation leads to these 3 things (not lmao):
- body can clear via cell-mediated response
- dry form: granulomatous lesions form with immune complexes
- wet form: vasculitis, effusion in pleural/abdominal space
what are the clinical findings with FIP?
essentially, a bunch of non-specific signs (incl. icterus)
most often it’s body cavity effusion (mainly peritoneum), also granulomas, ocular or neuro involvement
who does FIP target?
young cats (3mo-3yrs)
old cats (≥13yo)
male intact purebreds
antemortem diagnosis of FIP is really hard. what tests can you do in clinic to see if there’s FIP?
CBC: lymphopenia, NR anemia, thrombocytopenia
Chem: hyperglobulinemia, hyperproteinemia, albumin/globulun ratio<0.8, hyperbilirubinemia
UA: sometimes proteinuria
rads/US: look for effusion/granulomas
Fecal coronavirus antibodies (doesn’t differentiate b/t FECV and FIPV)
effusion analysis: looking for exudate (high protein count >3.5g/dL), low cellularity, pyogranulomatous effusion
RT-PCR on effusion: not definitive diagnosis, but confident
IHC = gold standard definitive diagnosis
how can you treat FIP?
GS-441524 (Remdesivir)
