FeLV si FIV Boli pisici an 5 curs Diagnostic si Profilaxie
Dr. Dragos Cobzariu
Sef Lucrari, FMV Bucureşti
Leucemia Infectioasa si Imunodeficienta Felina
DR. Dragos Cobzariu DVM PhD
FeLV si FIV Introducere
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are
among the most common infectious diseases of cats. Risk factors for
infection include male gender, adulthood, and outdoor access, whereas indoor
lifestyle and sterilization are associated with reduced infection rates.2–6
The retroviral status of all cats should be known. Cats may require
retrovirus testing at different times in their lives. Here are some general
principles for retrovirus testing:
A cat with a confirmed-positive test result should be diagnosed as
having a retroviral infection– not clinical disease. Diseases in cats infected
with FeLV or FIV may not necessarily be the result of the retrovirus infection.
Cats infected with FeLV or FIV may live for many years.
A decision for euthanasia should never be made solely on the basis of
whether or not the cat is infected. No test is 100% accurate at all times under all
conditions. All test results should be interpreted along with the patient’s health
and prior likelihood of infection.
All positives should be confirmed by another test method.
While they can be life-threatening viruses, proper management can
give infected cats longer, healthier lives.
Feline leukaemia virus (FeLV) is a retrovirus, which may induce
depression of the immune system, anaemia and/ or lymphoma
■ It affects cats worldwide. The prevalence of infection in Europe is
low(≤5%), although it may exceed 20% in some regions from
East Europe ( prevalenta 5-20% datorita lipsei de informare a
proprietarului si a vaccinarii, comertului cu animale fara a
cunoaste provenienta acestora, si lipsei metodelor de testare)
■ Over the past 25 years, the prevalence of FeLV infection has
dropped in US (datorita actiunilor sustinute de informare-
profilaxie si datorita testelor si vaccinurilor), thanks to reliable
diagnostic tests and vaccines.
Retrovirusurile sunt specifice fiecarei specii . Acest lucru înseamnă ca un
retrovirus felin, FIV va infecta numai pisicile, un retrovirus uman, HIV va
infecta numai omul.
Retrovirusurile sunt alcătuite din ARN. În gazdă, ARN-ul este transcris în
ADN și încorporat în ADN-ul celulelor gazdei.
Retrovirusurilor sunt fragile, fiind ușor inactivate de lumina ultravioleta,
caldura, detergenti, și uscare.
Particularitati structurale virusul FeLV
Cats with transient viremia
may develop persistent bone
marrow infection-Fast tests used
spleen, lymph node or small intestine
Peyer’s patches and timus develop
neutralizing antibodies clear blod viremia
Once marrow infected, remain latent infection for years ( 3-4
Latent infection can be present even though
serological tests are negative
blood and bone marrow are negative for virus by
Imunofluorescence, ELISA or viral culture, but viral genom can be
FeLV defective viruses that transduce cellular oncogenes – PCR
used to find them
■ Transmission of infection occurs through viral shedding (saliva,
faeces,nasal secretions, milk) by FeLV infected cats.(transmiterea
virusurilor se realizeaza prin secretii, excretii, lapte, bolurile de apa si
mancare custile de transport, litierele venite in contact cu pisicile
Transmission between cats occurs mainly through friendly
contacts(mutual grooming), but also through biting. (transmiterea se
poate face doar prin contact, muscatura, zgarietura)
■ In large groups of cats: ( distributia viremiei)
30-40% will develop persistent viraemia,
30-40% show transient viraemia and
20-30% seroconvert; a minority(IgM IgG)
(~5%) shows antigenaemia in the absence of viraemia
■ In viraemic queens, pregnancy usually results in embryonic death,
stillbirth or viraemic, ‘fading’ kittens(mortalitate embrionara, pisoi
■ Young kittens are especially susceptible to FeLV infection.
With age, cats become increasingly resistant( receptivitatea maxima o
au pisoii mici in primele saptamani de viata)
Clinic – suspicionam FeLV?
■ Most common(frecvent) signs of persistent FeLV viraemia are:
Anemia(mainly non-regenerative) Anemie
Imunosupresion (predisposition to other infections) Imunosupresie
Limfoma(thymic, alimentary, multicentric or atypical)Limfom
Most persistently viraemic cats die within two to three years
■ Less common(atipic):
Immune-mediated disease (haemolytic anaemia,
glomerulonephritis, polyarthritis) Boli autoimune
Chronic enteritis (crypt necrosis) Enterite cronice
Reproductive disorders (foetal resorption, abortion,
neonatal death and fading kittens) Probleme Reproductive
Peripheral neuropathies (anisocoria, mydriasis, Horner’s syndrome,
abnormal vocalisation, hyperesthesia, paresis, paralysis)
Neuropatii SN periferic
Patogeneza si Diagnostic
Replication in tonsils
Replication in draining lymph
Bone marrow Thymus Peyer’s patches
Protective Immune Response Inadequate Immune Response
PCR on Bone Marrow
Infection by oral route Infection by bite
genome (2 copies)
RNA dep. DNA pol
Soluble-antigen tests are preferred for initial screening.
Immunochromatographic FAST tests:
Agrolabo FeLV IC
Agrolabo FeLV/FIV IC
Agrolabo FeLV ELISA Ab Anti GP70
Agrolabo FeLV ELISA antigenic
While screening tests detect the presence of free antigen in
the circulating blood, the IFA tests for the presence of
antigen within infected white blood cells and platelets.
■ Supportive therapy (including fluid therapy if required) and good nursing care
■ Secondary infections should be treated promptly
■ Feline interferon omega may reduce clinical signs and extend the survival time
■ AZT (azidothymidine) may be used, but side effects may occur
■ Blood transfusions may prolong survival (Agrolabo RapidVet-H feline)
■ Asymptomatic FeLV + cats may live many years and end up dying of an
■ FeLV + cats need special care to avoid infections
■ FeLV infected cats should remain indoors and receive a regular clinical
check-up (every 6 months) (Carantina)
■ Corticosteroids, other immune-suppressive or bone marrow-suppressive
drugs should be avoided (Atentie! Imunosupresori – corticosteroizi)
■ The virus does not survive for long outside the host and is readily destroyed
by disinfectants, soap, heating and drying (Rezista putin in mediu)
■ However, the virus may survive in faeces; it remains viable if kept moist
at room temperature
■ All cats of uncertain FeLV status should be tested
prior to vaccination (Se recomanda testarea tuturor
pisicilor inainte de vaccinare, folosind testele rapide )
■ All healthy cats with a potential risk of exposure
(outdoor access, FeLV endemic area) should be vaccinated
■ Kittens should be vaccinated at 8 to 9 weeks of age, with a
second vaccination at 12 weeks, followed by a booster one
year later (Vaccinarea se face la varsta de 8-9 saptamani, cu
rapel la 12 saptamani, apoi la un an)
■ Inactivated vaccines are recommended
1.All cats of uncertain FeLV status should
be tested prior to vaccination!
La achizitionarea unei pisici solicitati
testarea ei cu:
pentru ai stabili statusul:
- Libera de FeLV
2. Most persistently viraemic
cats die within 3 to 4 years!
3.Anaemia in a cat with persistent
4.Alimentary lymphoma associated
with FeLV-clinical enteric sindrom
6.Primary visible signs of an FeLV
non-healing skin lesions
respiratory infections Haemobartonella felis
skin Ringworms-Microsporum, Tricophiton (Agrolabo - Dermakit)
5.Thymic lymphoma filling thethorax
of an FeLV infected cat
Prezentare de caz Stinky
Stinky's chronic problems
Stinky, a 4 year old neutered male, was presented to the clinic
in August 1992. He had been depressed and anorexic and for the
previous two days he had diarrhea with lots of mucous. Owner had
noticed a wound on the right side of his abdomen.
We examine Stinky and find:
Depressed, T= 39.5o, Pulse =144, yellow mucous membranes. Wound on right lateral
abdomen with palpable firm tract going ventrally. Oral cavity- large red plaque with small
white plaques under tongue - some ocular discharge - 8% dehydrated. When placing IV
catheter cat went into cardiac arrest - revived with external cardiac massage. Positive
pressure ventilation, IV epinephrine, bicarbonate, dexamethasone - later given mannitol IV.
CBC: Neutropenia with left shift and 2+ toxic change. PCV 0.24 - non regenerative SADB
(small animal data-base): bilirubin 40. 2+ icteric serum UA (urinalysis): strong positive for
bilirubin +2 blood 1+ bilirubin crystllauria SG 1.068.
Stinky's rescords show:
Stinky had a long history of chronic infections and problems that are summarized below:
Normal until 1990, except:
Chronic non-parasitic otitis externa overweight - 8kg, Began losing weight in mid-1990.
Developed suspicious number of abscesses and infected scratches after skirmishes with
workup shows :whitish grey plaques bilaterally in ear-canal - biopsies non-diagnostic no
radiographic evidence of otitis media... otitis resolved after antibiotic treatment
Stinky's rescords show:
Spring 1991: Hair coat shows marked thinning,
presumably pruritic as cat is constantly grooming.
Skin and hair samples show evidence of
Culture on dermatophyte medium – Dermakit-
heavy growth of Trichophyton equinum and another
obscure dermatophyte that is not normally pathogenic
treated with oral ketoconazole –resolved in 2 weeks, hair coat improved.
Fall 1991: Upper respiratory tract problems but no etiological agent could
Spring 1991: Alopecia and pruritus returned. URT problems still there.
alopecia treated with oral vitamin E
You decide to see if Stinky's chronic problems are related to FeLV infection.
• What should you do?
• What samples do you need to take?
• What does the tests determine?
• What do the results mean?
Stinky's test show that he is FeLV ELISA-FastKit: positive, FeLV PCR:
What is you opinion?!
Prezentare caz Emily-4luni
Emily was a 4 month old female Siamese. She was apparently healthy until the
previous day when she was caught under the leg of a recliner chair. She has
had difficulty breathing since then. A physical examination showed that Emily
had trouble breathing - Inspirational effort, marked pleural effusion present.
Her chest showed more than normal resistance to compression.
There is a medium to large volume of pleural fluid with associated lung
collapse. The mediastinum is abnormally dense. The heart is difficult to assess.
Progress exam. No.1 - There is an increased volume of pleural fluid with further
Progress exam No 2 - Again there is an increase in pleural fluid indicating
active fluid formation or hemorrhage, as the case may be.
Reassessment of the abdomen indicates an almost certain cranial mediastinal
mass as seen in the dorsoventral view.
This latter diagnosis, although unsuspected in the context of the proposed
trauma, was confirmed on the basis of the palpable mass in the mediastinum.
the reason for the rapid fluid formation is uncertain. Possibly, trauma might
cause hemorrhage in a mass or a mass may erode regional vasculature to
produce such blood tinged fluid as it is removed from this cat's thorax on
Gross necropsy: Ventral mediastinal area contains a nodular, grey-
white mass-- approximately 3 X 3 X 6 cm in size. Both right and left
lung lobes appear atelectatic and there is a 2 cm tear in the posterior
mediastinum. A single sub lumbar lymph node is visibly enlarged.
Sections of mediastinal mass contain a uniform population of
lymphoblast like cells. These cells have roughly circular nuclei, some
have prominent nucleoli and most have minimal cytoplasm that has ill
defined margins. There are scattered foci of necrotic cells and
hemorrhage. Similar cells have replaced the sub lumbar lymph node
that was sectioned and are also present in sinusoids and portal areas of
A section of the liver shows cells that stain with anti GAG antibody as
well as antibody against CD3.
• How would you interpret the results of the immunohistochemistry?
• Was the tumor induced by a feline retrovirus?
• How did a young 4 month old kitten develop rapidly
growing retrovirus induced tumor?
Feline immunodeficiency virus- FIV
First isolated in 1986, (FIV) is a retrovirus-lentivirus
closely related to HIV. Most felids are susceptible to FIV,
but humans are not.
■ FIV is endemic in domestic cat populations worldwide
(4 subtypes A and B are most common in Europe)
■ Seroprevalence of FIV varies greatly between regions
■ Sick adult cats, male cats and free-roaming cats are
most likelyto be infected
■ FIV loses infectivity quickly outside the host and is
susceptible to all disinfectants including common soap
Infectia cu FIV
■ Most FIV infections are acquired by bites (fights,
mating) from persistently infected cats. The risk of
transmission is low in households with “socially well-
adapted cats” (Transmiterea – frecvent prin muscaturi)
■ Transmission from mother to kittens may occur,
especially if the queen is undergoing an acute
infection (Transmiterea de la mama la pui frecvente
■ FIV infected cats are persistently infected in spite of
their ability to mount antibody and cell-mediated
Patogeneza infectiei cu FIV
(virus shed in saliva)
Virus infects B-cells,
T-cells and macrophages
(Swollen Lymph nodes)
Reversed CD4:CD8 ratios
(Opportunistic infections, B-cell Lymphomas)
Clinic – suspicionam FIV?
Infection has a long latent or ‘asymptomatic’ phase. Infected cats
generally remain free of clinical signs for several years, and some
cats never develop disease. (Perioada de latenta – lunga.
Semnele clinice pot lipsi ani de zile sau pe tot timpul vietii)
Clinical signs are not caused by FIV, but are the consequence of
immunodeficiency(CD4+/CD8+ decreased ratio)
■ Typical manifestations are:
May last a few days to few weeks (cateva zile cateva saptamani)
Fever and malaise may go unnoticed (febra)
Acute enteritis (diarrhea), stomatitis, dermatitis, conjunctivitis,
respiratory tract disease (enterite, stomatite, dermatite,
conjunctivite, inflamatii ale tractusului respirator)
Generalized lymph node enlargement common (marirea in volum a
Clinic – suspicionam FIV?
Follows acute phase
Appear clinically healthy
May last for years
Use to say would become ill within 5 years
Now know that many FIV + cats can live “normal
lives” for much longer
FIV is not a death sentence
Clinic – suspicionam FIV?
- No good predictor of when this phase will occur
- Characterized by opportunistic infections, neoplasia or other
syndromes such as wasting (infectii oportuniste, neoplasm)
bacterial, fungal, and protozoal (Toxoplasmosis, Ringworms)
treatment is directed at the secondary condition
- Chronic gingivostomatitis (stomatita cronica)
- Lymphadenopathy (limfadenopatie)
- Renal failure associated with immune-mediated
glomerulonephritis (glomerulonefrita autoimuna)
- Chronic rhinitis and - weight loss (rinita cronica, pierdere in
Examenele de laborator
None are specific for FIV but
Resolves as progresses to asymptomatic phase
CBC and chem panel normal during asymptomatic phase
Clinically ill cats may have
anemia, neutropenia, lymphopenia (seen in 1/3 –
1/2 of cats), thrombocytopenia
Cytopenias may reflect secondary disease or may be
suppression of bone marrow precursors by the FIV
FIV produces a persistent, life-long infection, so detection of
antibodies in peripheral blood has been judged sufficient for
routine diagnostic screening (screening epidemiologic) if
the cat has not been previously vaccinated against FIV and has
not acquired FIV antibodies in colostrum.21, 22
ELISA and other immunochromatographic tests are the
preferred screening tests:
Agrolabo FIV ELISA antibody
Agrolabo FIV IC
Agrolabo FeLV/FIV IC
Confirmation of positive screening tests should include a
different method or at least an antibody test from a different
■ Vaccination of cats against FIV induces anti-FIV antibodies . These
antibodies persist for at least one year and can be transferred in
colostrum to kittens.
■“Discriminant ELISA” was reported by Dr. Levy and co-workers from
the University of Florida, can differentiate between antibodies
produced after FIV vaccination and antibodies produced after FIV
■ While polymerase chain reaction (PCR) assays may help distinguish
cats infected with FIV from cats vaccinated against FIV, one study
found marked variability in diagnostic accuracy among commercial
■ Positive in-practice ELISA test results obtained in a low-prevalence
or low-risk population should always be confirmed by a laboratory
■ Western blot or IFA are the ‘gold standard’ laboratory test for FIV
■ PCR-based assays (for proviral DNA) are variable in performance and
may even be inferior to serological tests
Diagnostic-rezultate fals pozitive!
Want to confirm diagnosis with IFA –CYF or Western
Immunoblot antibody testing in asymptomatic cats
IFA same accuracy of ELISA but may decrease
technical error by sending to lab
Western blot considered “gold standard” for
confirming a positive
Kittens from FIV infected queens may test seropositive
due to persisting maternal antibodies, and should be
retested at 16 weeks of age. Exceptionally, kittens may
remain seropositive until 6 months of age
Diagnostic-rezultate fals negative!
False negatives occur due to:
Anergic stage of disease (terminal phase)
Early infection and lack of seroconversion
Lack of seroconversion due to immunosuppression or
seroconversion occurs later in disease (up to 6 months
*Most cats seroconvert within 2-4 weeks post-exposure but
may take up to 8 weeks
■ Cats should never be euthanised only on the basis of an FIV
positive test result, cats may live as long as uninfected cats.
■ Neutering is recommended to reduce aggression and decrease
■ FIV infected cats should receive regular (6 monthly) veterinary
health checks including routine biochemistry, haematology and
■ Prompt and accurate diagnosis of any secondary illness is essential
■ FIV infected cats can be housed in the same ward as other
patients, but should be kept in individual cages separate from
cats with contagious conditions
■ In rescue shelters, cats should be housed individually to avoid
(at the very least, FIV positive cats should be segregated)
■ Feline interferon omega may reduce clinical signs and
extend the survival time (interferon)
■ AZT (azidothymidine) may be used, but side effects may
■ Surgery is well-tolerated by asymptomatic FIV infected
cats, but perioperative antibiotic treatment should be used
in all cases (obligatoriu – antibiotic post-operator)
■ Care must be taken to avoid iatrogenic virus
transmission (e.g. by thorough decontamination of
surgical instruments that have been used on seropositive
■ Avoid use of Griseofulvin for dermatophyte infections
(increased susceptibility to neutropenia)
■ In Europe at present there is no FIV vaccine
■ Vaccination against routine pathogens can be
considered for healthy seropositive cats but is not
recommended for sick, FIV infected cats
■ Fel-O-Vax® FIV (Fort Dodge)
new vaccine available on the market
minimal side effects
Efficacy quoted to be 82% but heavily disputed
Protects against Subtype A and D of FIV
Subtype B FIV probably more common
Vaccine titer and infectious titer not distinguishable on ELISA or
Western blot testing and will make diagnosis of the disease very
1.FIV positive cats (like this one) may live
as long as uninfected cats
2.Chronic infections may arise
due to FIV Infection
3. Cats should never be euthanised
on the basis of an FIV positive
4.Chronic infections may arise
due to FIV Infection gingivitis,
stomatitis, otic infections
5.Weight loss and haemorrhagic
enteritis in an FIV positive cat
FeLV Algoritmul de Diagnostic
All positive results should be confirmed, especially asymptomatic and
low-risk cats. Re-test immediately with IFA/ELISA
Negative screening test results are highly reliable. However, if results are
negative but recent infection cannot be ruled out, testing should be repeated
a minimum of 30 days after the last potential exposure (Supraveghere
epidemiologica – 3 testari la un interval de 30 de zile efectuate pe un numar
cat mai mare de animlae – preferabil toate animalele din efectiv)
Discordant results may be due to the stage of infection, the variability of
host responses or technical problems with testing. It is not usually possible
to determine the true FeLV infection status of cats with persistently
discordant test results.
Negative results for either FeLV or FIV are much more reliable because of the
low prevalence of infection in most cat populations.
No test is 100% accurate all the time, under all conditions. In cat populations
with a low prevalence, for example less than 0.5%, more than half of the cats
that test positive are likely to be uninfected.26
FIV Algoritmul de Diagnostic
Cats vaccinated with a whole-virus vaccine will test antibody-positive. Re-test with another
Negative screening test results are highly reliable. However, if results are negative but recent
infection cannot be ruled out, testing should be repeated a minimum of 60 days after the last
potential exposure. (Necesitatea repetarii testului dupa 60 de zile)
If positive after kitten reaches 6 months old, consider FIV-infected and continue appropriate
management program. (Anticorpii maternali persista in organism maximum 6 luni de zile)
May also consider utilizing alternative test methods such as culture or PCR where available.
If negative at any interval, consider free of infection and begin wellness program.
Kittens may be tested for FeLV and FIV at any age. Most kittens test negative, indicating no
infection. Antibody tests for FIV can detect antibodies passed in colostrum from an infected or
vaccinated mother, which can be mistaken for infection in the kitten.
FeLV vaccinations will NOT induce positive test results.
FIV vaccinations WILL induce positive test results.
Managmentul Cazurilor Pozitive
Examinations should be performed at least twice a year and at each visit:
Update medical history. Monitor for any signs of weight loss.
Perform a thorough physical exam; pay close attention to lymph nodes,
eyes and oral cavity.
Perform a complete blood count, biochemical analysis, urinalysis, and
fecal examination at least once a year. FeLV cats may need a complete
blood count twice a year.
Spay or neuter intact cats. Control internal and external parasites.
Vaccinate as lifestyle indicates. Most retrovirus-infected cats mount
adequate immune responses when vaccinated, and there is no need to
modify standard vaccination intervals.28
There is controversy about the use of inactivated versus modified-live
vaccines. Current recommendations are to use inactivated vaccine
products due to the theoretical risk of a modified-live product regaining
its pathogenicity in cats with compromised immune systems.
Infected queens should not be bred and should be spayed if their
condition is sufficiently stable to permit them to undergo surgery.
Managmentul Cazurilor Pozitive
Prompt and accurate diagnosis is essential to allow early therapeutic
intervention and a successful treatment outcome. Therefore, intensive
diagnostic testing should proceed early in the course of illness for
Many cats infected with FeLV or FIV respond as well as their uninfected
counterparts to appropriate medications and treatment
strategies,although a longer or more aggressive course of treatment
may be needed.
Few attempts have been made to evaluate anti-viral drugs,
immunomodulators, or alternative therapies in large controlled studies
of naturally infected cats. To date, no treatment has been shown to
reverse well-established retrovirus infection in cats.
Clients with a healthy or ill retrovirus positive cat may be frightened by
the initial diagnosis.
It is important to alleviate these fears when appropriate and offer
encouraging advice on the proper care and management of the cat.
LIMITAREA TRANSMITERII FeLV-FIV
In the veterinary Practice
Retroviruses are unstable outside their host animals and can be quickly
inactivated by detergents and routine disinfectants.13–17
Simple precautions and routine cleaning procedures will prevent transmission
of these agents in veterinary hospitals.
As a guide:
All infected patients should be housed in individual cages and not in
isolation/contagious wards where they may be exposed to infectious agents.
Staff should wash their hands between patients and after cleaning cages.
Because FeLV and FIV can be transmitted in blood transfusions, donors
should be tested prior to donating. A real-time PCR test for FeLV is also
recommended for blood donors as proviral elements in seronegative cats with
regressive FeLV infection may cause infection in transfusion recipients.
Dental and surgical instruments, endotracheal tubes and other items
potentially contaminated with body fluids should be thoroughly cleaned and
sterilized between uses.
Fluid lines, multi-dose medication containers and food can become
contaminated with body fluids (especially blood or saliva) and should not be shared
LIMITAREA TRANSMITERII FeLV-FIV
Limiting transmission – At home
Confine – Infected cats should be confined indoors so they do not pose a
risk of infection to other cats and so they are protected against infectious
hazards in the environment.
Isolate – The best method of preventing spread to other cats in the
household is to isolate the infected cat from interacting with its
housemates. Isolation to a separate room is recommended, but a simple
screen or chain-link barrier is adequate. Generally, FIV transmission is low
in households with stable social structures where housemates do not fight,
but FeLV can still be transmitted via friendly interactions.
Don’t Introduce – If separation is not possible, no new cats should be
introduced in the household to reduce the risk of territorial aggression.
If owners choose not to separate retrovirus-infected housemates from their
other cats, the uninfected cats should be consideredfor vaccination.
Vaccinated cats should be isolated from infected cats for at least two
months after the vaccine series is completed.
LIMITAREA TRANSMITERII FeLV-FIV
Prevention of FeLV and FIV transmission in Shelters and Catteries
As for pet cats, it is ideal for all cats in shelters and catteries to be tested for FeLV and FIV.
Testing at admission is optional for singly-housed cats in shelters, but all cats in breeding catteries should be
tested. Testing is highly recommended for group-housed cats. If not performed prior to adoption, testing
should be recommended to the new owner before exposure to other cats.
Testing should be repeated 60 days after the initial test and annually for cats kept in long-term group
Each cat should be individually tested. Testing representative kittens in a litter or colony and extrapolating
results to other cats in the group is unreliable. Procedures such as pooling multiple samples for use in a single
test reduce test sensitivity and should not be performed.
Both foster families and adopters should have their own resident cats tested prior to fostering or adopting a
FeLV vaccination is optional for singly housed cats. Cats should test negative prior to vaccination. FeLV
vaccination is highly recommended for all cats housed in groups and for both foster cats and permanent
residents in foster homes.
In catteries that follow testing guidelines and maintain retrovirus-negative status, vaccination against FeLV
and FIV is not necessary.
Vaccination is not 100% effective and should never be used in place of a test and segregate program.
In contrast to the case for feline panleukopenia, herpesvirus and calicivirus vaccines, the value of a single FeLV
vaccine for feral cats has not been determined. Therefore, FeLV vaccination is not recommended for feral cat
trap-neuter-return programs if program resources are needed for higher priorities.
FIV vaccination is not recommended for use in shelters or feral cats.
Strict adherence to universal precautions is required to prevent iatrogenic transmission of retroviruses in the
shelter environment via contaminated equipment and secretions.
“You don’t have to consider it a death sentence. First of all, you’d do
well to have the animal retested after about three months, since
the original test may have yielded a false positive.
Secondly, some FeLV-infected cats develop an effective immune
response, which controls the viral infection and results in a
transient viremia instead of a persistent viremia.
In these cats, subsequent FeLV tests will show that the cat no
longer has virus in its blood.
Finally, while there is no complete cure for FeLV or FIV infection,
newer treatments and supportive care can often result in several
years of relatively good health.”
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of Feline Practitioners’ feline retrovirus management guidelines.
Journal of Feline medicine & surgery 10 (3): 300-316.
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of feline leukemia virus and feline immunodeficiency virus infection
among cats in North america and risk factors for seropositivity.
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