Difference between revisions of "Feline Leukemia Virus"

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Feline Leukemia Virus is commonly abbreviated to FeLV
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#REDIRECT[[Feline Leukaemia Virus]]
 
 
====Antigenicity====
 
*Main envelope protein: gp70
 
*3 antigenic subgroups:
 
*Group A
 
**is transmitted between cats
 
**is monotypic: one vaccine covers all isolates
 
**causes '''lymphosarcoma'''
 
*Group B:
 
**is recombinant with transmissible FeLV-A
 
**increases the chance of '''thymic tumors'''
 
*Group C:
 
**is a mutant of A
 
**isolates are rare, and occur as A+C mixtures
 
**increases chances of '''anemia'''
 
 
 
====Pathogenesis====
 
*FeLV is the "disease of friends": transmission usually occurs through '''mutual grooming'''
 
*From the oropharynx, virus spreads to most tissues in the body to replicate, notably:
 
**Bone marrow
 
**Thymus
 
**Salivary glands
 
**Reproductive tract
 
*Most kittens but only 30% of adults become '''viremic''' for life without producing antibody
 
**20% of viremic cats die of tumors
 
**30% of viremic cats die of FeLV-associated disease
 
**80% die within three years of exposure
 
*30% of adults exposed become '''latently infected''' and can become viremic when immunosuppressed
 
*40% of exposed adults remain healthy and develop Ab and CD8+ Tcells after clearing the virus, without becoming reinfected or silent carriers
 
 
 
Clinical Signs:
 
*'''Leukemia'''
 
*'''Multicentric lymphosarcoma''': B or T cell tumors, which may be palpable as enlarged lymph nodes (particularly mesenteric)
 
*'''Thymic lymphosarcoma''': T cell tumors, with only the thymus enlarged
 
**Results in dyspnoea
 
**Confirmed by radiography
 
*'''Alimentary lymphosarcoma''': B cell tumors of the Peyer's patches
 
 
 
FeLV-associated disease:
 
*'''Immunodepression''' causing secondary disease
 
*'''Reproductive failure''': FeLV crosses the placenta, causing fetal resorption or viremic kittens with thymic aplasia
 
 
 
====Epidemiology====
 
*Vertical transmission of FeLV-A from mother to kittens either via placenta, grooming, or milk
 
*Horizontal transmission occurs via saliva during mutual grooming
 
*Recovery linked to age and presence of maternal antibody
 
*Particular concern for intensively bred cats because of crowding, etc.
 
 
 
====Diagnosis====
 
*FeLV should be suspect in any cat with '''recurrent bacterial infections''', '''anemia''' or '''weight loss'''
 
*'''ELISA''' for '''Antigen''' (capsid protein p27 or envelope protein gp70)
 
*'''Immunochromatography''' is now trusted as ELISA testing can give false positives
 
*'''Virus isolation''' from heparinised blood can now be performed to confirm a positive diagnosis
 
 
 
====Control====
 
*Antigen positive sick cats should be destroyed
 
*Healthy positive cats should have diagnosis confirmed
 
*Vaccination:
 
**Should take place once antigen-negative status has been determined
 
**'''Leukogen''': Subunit vaccine (using envelope protein gp70) produced in ''E. coli'' mixed with Quill-A and alhydrogel
 
**Others include inactivated virus and canarypox recombinants, but all MUST include FeLV-A
 
[[Category:Mammalian Type C retrovirus ]][[Category:Cat]]
 
[[Category:To_Do_-_Clinical/Viruses]]
 

Latest revision as of 14:10, 12 August 2010