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