Feline Retroviral Diseases Flashcards

1
Q

What are the 2 major Retroviruses that affect cats?

A
  1. feline leukemia virus (gamma)
  2. feline immunodeficiency virus
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2
Q

What are the FeLV proteins that are found on its core and envelope?

A

CORE = p27 - produced by infected cells and detected by FeLV antigen tests

ENVELOPE = gp70 - responsible for attachment to infect cells, neutralizing Ab produced against it

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3
Q

What signalment is most commonly affected by FeLV? What are the 2 modes of transmission?

A

young, outdoor kittens in large populations

  1. high amounts in plasma - close contact, bite, mutual grooming
  2. vertical - in utero, nursing

(short survival in the environment)

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4
Q

What are the 5 steps to the pathogenesis of FeLV?

A
  1. oronasal exposure
  2. viral replication in local lymphoid tissue
  3. lymphocytes infected, circulate, and cause low-level viremia
  4. systemic infection of lymphoid tissue = LNs, spleen
  5. bone marrow infection = persistent high-level viremia affecting granulocytes and platelets
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5
Q

What are the 3 possible outcomes of FeLV infection?

A
  1. progressive infection = permanent, systemic infection and viremia, high risk of clinical disease, FeLV test positive
  2. abortive infection (regressor) = virus never spreads beyond local lymphoid tissue, no viremia
  3. regressive infection (transient, latent) = no persistent viremia, viral DNA incorporated into genome of infected cells
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6
Q

FeLV:

A
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7
Q

What is prognosis of FeLV like?

A
  • 80% die within 3 years, will most likely develop disease
  • survival time can possibly be extended with supportive care
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8
Q

What is the most common disease related to FeLV? What does it make these cates predisposed to?

A

potent immunosuppression

  • recurrent infections
  • FIP, FIV
  • hemotropic mycoplasma
  • chronic stomatitis and rhinitis
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9
Q

What is the most common hematologic disorder seen with FeLV? What is this a result of?

A

nonregenerative anemia - red cell aplasia due to a lack of early erythroid precursors = MACROCYTOSIS

infection of bone marrow elements

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10
Q

What 6 other hematologic disorders can be seen with FerLV?

A
  1. aplastic anemia - pancytopenia due to a lack of production of all cell lines
  2. hemolytic anemia
  3. anemia of chronic disease
  4. myelophthisis - normal marrow space is infiltrated and replaced by nonhematopoietic or abnormal cells
  5. thrombocytopenia
  6. neutropenia
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11
Q

What 2 things is hemolytic anemia due to FeLV associated with?

A
  1. immune-mediated
  2. Mycoplasma haemofelis infection due to immunosuppression
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12
Q

How can patients with FeLV develop neoplasia? What neoplasias are associated?

A

recombination of FeLV-A with a cellular oncogene forms and recombinant virus

  • FeLV-B or feline sarcoma virus
  • lymphoma
  • fibrosarcoma
  • leukemia
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13
Q

What are the 2 most common neoplasias associated with FeLV? Why does it make diagnosis difficult?

A

lymphoma and leukemia

cats with lymphoma will likely test negative on FeLV antigen tests

  • high prevalence of viremia in mediastinal lymphoma
  • low prevalence of viremia in alimentary lymphoma
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14
Q

What immune-mediated, reproductive, and neurologic diseases are associated with FeLV infection?

A

IMMUNE - glomerulonephritis, polyarthritis, uveitis

REPRO - infertility, fetal absorption

NEURO - spastic pupil syndrome, urinary incontinence, paresis

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15
Q

What 4 miscellaneous syndromes are associated with FeLV infection?

A
  1. enteritis
  2. hepatopathy
  3. Fading Kitten Syndrome - newborn kittens fail to thrive and are likely to expire prematurely, usually prior to weaning
  4. osteochondromatosis
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16
Q

How is FeLV diagnosed? How does it compare to other methods?

A

SNAP ELISA detects p27 soluble antigen not seen in cells

very sensitive and specific —> more sensitive than IFA

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17
Q

When can FeLV-positive patients begin to test positive on SNAP tests? How is it confirmed?

A

within 4 weeks of infection

repeat test or perform an IFA

18
Q

What are 3 possible causes of a positive FeLV ELISA?

A
  1. viremia present
  2. progressive or regressive infection
  3. (rare) false positive
19
Q

What are 4 possible causes of a negative FeLV ELISA?

A
  1. no exposure
  2. recently exposed, but not viremic
  3. abortive or regressive infection
  4. false negative
20
Q

How does an FeLV IFA test work? When is it positive?

A

detects p27 antigen in cells (WBCs, platelets) on a blood smear or bone marrow biopsy/aspirate

progressive infection

  • early transient viremia does NOT result in a positive IFA, since the virus is not in the cells
  • false positive likely
21
Q

What are the 2 possibilities of negative FeLV IFA tests?

A
  1. not exposed
  2. transient viremia or cytopenias = false negative
22
Q

What can a positive ELISA and negative IFA in a possible FeLV patient mean?

A
  • transient viremia
  • low level cell-associated viremia (cytopenia)
  • false positive ELISA (rare)
23
Q

What can a negative ELISA and positive IFA in a possible FeLV patient mean?

A

most likely a false positive IFA

24
Q

What 6 types of cats should be tested for FeLV?

A
  1. newly acquired - at adoption AND 28 days later
  2. known exposure to infected cells
  3. ill cats
  4. cats with high risk lifestyles
  5. prior to FeLV vaccination
  6. blood donors
25
Q

What is considered a high-risk lifestyle for becoming infected with FeLV?

A
  • outdoor cats
  • those housed with infected cats
26
Q

How is FeLV treated?

A

SUPPORTIVE, treat associated diseases

  • anemia: transfusion, EPO
  • neutropenia: antibiotics, G-CSF
  • myelodysplasia: G-CSF, cytosar
  • gingivitis: dental cleaning, extractions, antimicrobials
  • infections: antimicrobials
  • neoplasia: chemotherapy
  • immune-mediated: glucocorticoids
27
Q

How is FeLV infection prevented?

A
  • keep cats indoors
  • test prior to introduction of new cats
  • vaccination
28
Q

What is the FeLV vaccine like? What should be done before it is given?

A
  • not a core vaccine - recommended for catteries, outdoor cats, FeLV+ household, and kittens regardless of lifestyle
  • efficacy not as high as others, preventable fraction 85-90%

ELISA test —> no need to vaccinate infected cats

29
Q

How does a prior FeLV vaccination affect SNAP ELISA tests?

A
  • DOES NOT cause a positive FeLV test
  • DOES cause a positive FIV test
30
Q

What vaccines are associated with sarcomas? How do they develop? How has this changed how vaccines are given to cats?

A

rabies and FeLV —> risks outweigh rabies and FeLV infection!!

chronic granuloma formation is response to vaccine or adjuvant

commonly administered SQ in distal hind limbs, keep cat to monitor vaccination site —> consider excision if a nodule persists for >3 months

31
Q

How do vaccine-associated sarcomas act?

A

invasive and high metastatic potential —> excise with large margins and perform radiation

32
Q

What are the 5 steps to the pathogenesis of FIV?

A
  1. infection of local lymphatic tissue
  2. viremia with dissemination to other tissue
  3. depletion of CD4+ cells
  4. decreased function of all lymphocytes
  5. immunosuppression
33
Q

What are the 2 major risk factors associated with FIV? What are the modes of transmission?

A
  1. males
  2. outdoor cats

bite wounds and vertical through placenta or nursing

34
Q

What are the 3 most common clinical findings seen with FIV?

A
  1. transient and mild signs in the initial stage
  2. chronic = immunosuppression —> recurrent infections, stomatitis
  3. no signs
35
Q

What is most commonly seen on CBC and chemistry in patients with FIV?

A

CBC = neutropenia, lymphopenia, anemia

CHEM = hyperglobulinemia

36
Q

What are the 2 ways of diagnosing PIV?

A
  1. FIV antibodies seen with ELISA or Western blot
  2. PCR - false negatives and positives possible
37
Q

What are the 4 possibilities of a positive FIV antibody test?

A
  1. infected
  2. vaccination
  3. false positive
  4. maternal antibodies if less than 6 m/o
38
Q

What are the 2 possibilities of a negative FIV antibody test

A
  1. not infected
  2. infected, but not seroconverted - takes 8 weeks to 6 months
39
Q

What treatment is available for FIV? What does it do? What side effect is commonly seen?

A

Azidothymidine (AZT) - nucleoside antiviral

cat remains infected, but it improves clinical condition, QoL, immune status, and survival

anemia in the first month

40
Q

How does the prognosis of FIV compare to FeLV?

A

cats with FIV did not have a significant difference in survival compared to cats without FIV

FIV does NOT affect longevity, unlike FeLV