Feline Retroviruses Flashcards
what are exogenous feline retroviruses
feline leukemia virus (FeLV)
feline immunodeficiency virus (FIV)
feline syncitium forming virus (FeSFV)
what are endogenous feline retroviruses
endogenous FeLV
RD-114
what type of virus is feline leukemia virus
retroviridae
do cats recover from feline leukemia virus
most do
diseases only in persistently infected cats
high mortality rates in persistently infected cats (young cats)
how is FeLV spread in the cat
oropharynx
regional lymph nodes
bone marrow
other organs
salivary glands
If persistent infection occurs in the bone marrow, infected white blood cells and platelets leave the bone marrow with ultimate infection of epithelial structures including salivary and lacrimal glands
how is FeLV transmitted
prolonged contact with an infected cat saliva and nasal secretions
grooming or sharing common water or food sources
the organism doesn’t survive in environment (fomite transmission unlikely)
where does latent FeLV occur and what is the significance of latent infections
Bone marrow:
- Role of VN antibodies
Significance:
- No FeLV diseases
- Reactivation
- Steroids
- Pregnancy
- Transmission
what are the outcomes of FeLV infection
what is the pathogenesis of FeLV
Mutation
- FeLV subgroup C
Recombination
- FeLV subgroup B
- FeSV
Insertion
- Apoptosis
- Oncogenes
- Myc, fes
what are the main diseases caused by FeLV
immunosuppression
anemia
neoplasia
what are the malignant diseases causes by FeLV
lymphoma
leukemia
fibrosarcoma
what are the lypmhomas that felv causes
thymic
alimentary
multicentric
what are the leukemias that felv causes
myeloid
erythroid
reticuloendotheliosis
what other diseases can felv cause
immunosuppression
anemia
- myelofibrosis
- pure red cell aplasia
- medullary osteosclerosis
Glomerulonephritis
infertility
what causes anemia in the FeLV positive cat
immunosuppression
- haemobartonella fellis
FeLV-C
- pure red cell aplasia
neoplasia
- myelophthesis
- hemorrhage
- organ dysfunction
auto-immunity
what are the patterns of FeLV infections
Mutlicat FeLV +ve households
- All cats exposed to infection
- Many cats viremic (40%)
Single cat households
- Lower frequency of exposure to FeLV (50%)
- Few cats viremic (1%)
Age related resistance
- Young cats overrepresented
what is the immune response to felv
felv neutralizing antibodies
- Directed against gp 70
- Inactivate virus
- Protect against challenge
- Significant lag phase between recovery and detection
cytotoxic T cells
- higher numbers found in recovered cats
NK cells, complement etc
- largely unknown
when would you want to test for felv
Sick cat
Revaccination
Breeding cat screening
what are the methods of diagnosis of felv
RIM assay
CITE assay
ELISA
Virus isolation
Immunofluorescence
how is felv treated
Healthy cats
- ISOLATE + RETEST IN 12 WEEKS
- No practical treatment
In contact cats
- Vaccinate
Sick cats
- Euthanasia
- Immunosuppression, anemia, neoplasia
how is felv controlled
test and remove
vaccination
describe a control programme where all cats are tested in a household and what outcomes if a cat tests positive/negative
what are the vaccines for felv
Inactivated virus
- Fevaxyn
- FeLV-A +/- FeLV-B
Subunit
- Leukocell 2
- FeLV-A, B & C
Recombinant surface protein
- Leucogen, Nobivac, Leucofeligen
- FeLV-A
Recombinant viral vector
- Purevax
- FeLV-A
what are the issues with felv vaccine
Efficacy of vaccines
- Target subgroup
- VN antibodies
- Varied
- Protection fraction of population
Use of vaccines
- Timing
- Pre-vaccination testing
- Age related susceptibility
what are the features of lentiviruses
genomic variability
cell to cell transmission
persistent infections
long incubation periods
what type of virus is feline immunodeficiency virus
retroviridae subfamiliy lentivirus
what is the mode of transmission of FIV
FIV replicates in oral lymphoid tissues
biting behaviour is primary route of transmission – older, male outdoor cats susceptible
transplacental and perinatal transmission occurs from infected queens to kittens
what are the stages of FIV infection
PNL
- pyrexia, neutrophilia, lymphopenia
Latency
PGL
- persistent generalized lymphadenopathy
ARC
- AIDS related complex
AIDS
- acquired immunodeficiency syndrome
what are the primary diseases associated with FIV
Increased risk of tumours
- 5x more than average normal healthy cat
- But lower than FeLV
Neurological disorders
- Virus can get into brain
Lymphadenopathy
Lymphopenia
Pyrexia
Wasting
what are secondary diseases associated with FIV
Chronic stomatitis/gingivitis?
Chronic URT infections?
Chronic diarrhea?
Chronic skin diseases
- Parasitic — demodex
- Fungal — variety
- Bacterial — mycobacterial
- Viruses — cowpox
Other opportunistic infections?
what has an impact on FIV positive cats wellbeing/disease progression
Management & housing conditions have impact on disease progression and survival times of FIV-positive cats
how is FIV diagnosed
RIM assay
Antigen ELISA
Immunoblotting
Virus isolation
how is FIV treated
Antibiotics
Other specific drugs as infected
Corticosteroids?
Inflammatory
Anti-HIV drugs
- AZT
- PMEA
- ddI, ddC
- Severe side effects and toxic
Euthanasia
what are the lab features of FIV
neutropenia
thrombocytopenia
non regenerative anemia
monocytosis and lymphocytosis
how is FIV controlled in multicat households
Cats that are positive will not revert to being negative (compared to FeLV)
is there FIV vaccine
Problems
- Virus variation
- Nature of immune response
Primucell FIV
- Not proven to be protective
- May cause antibody dependent enhancement
- Interferes with virus testing using ELISA etc
Other solutions?
what is the prognosis of FIV positive cats
impossible to predict the survival of a given cat infected with FIV, cats infected with FIV can live very normal, healthy lives for many years if managed appropriately
for a healthy cat diagnosed with FIV, the most important management goals are to reduce their risk of acquiring secondary infections and prevent the spread of FIV to other cats.
what is the causative agent of feline infectious anemia
formerly known as Hemobartonella
Mycoplasma hemominutum (small)
Mycoplasma hemofelis (large)
what type of anemia does feline infectious anemia cause
regenerative
immunosuppression – severe anemia
what are the hematological findings of feline infectious anemia
anemia (MCV increases with time)
reticulocytes increase
jaundice
coombs test
what are ddx for feline infectious anemia
IMHA
onion poisoning
heinz body anemias (oxidative stress – diabetes mellitus)
how is feline infectious anemia diagnosed
direct ID difficult
- Freshly prepared smears and experience
- Stain artifacts can look very similar
- Many cats have low numbers of parasites
PCR
- asymptomatic infections
what are predisposing factors for feline infectious anemia
FeLV
stress
neoplasia
how is feline infectious anemia treated
tetracyclines induce a temporary remission
- 3 weeks minimum
- Several side effects
- Give water after administration
- Enrofloxacin is a proposed alternative
Prednisolone
- May help if initial response is poor
what are the differences between FeLV, FIV and FIA
FeLV
- disease of young cats, usually fatal
- widespread immunity & vaccines
FIV
- infection of older cats, rarely fatal
- no immunity and no effective vaccines
FIA
- anemia in any cat
- hard to diagnose, worth the effort
what are the core vaccines for cats
feline panleukopenia
feline calicivirus
feline herpes virus 1
what are the non-core vaccines for cats
bordetella bronchiseptica
chlamydia felis
feline leukemia virus
feline immunodeficiency virus
feline infectious peritonitis
rabies
