Difference between revisions of "Feline Leukemia Virus"
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(Redirected page to Feline Leukaemia Virus) |
m (moved Feline Leukemia Virus (FeLV) to Feline Leukemia Virus) |
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− | + | {{unfinished}} | |
+ | |||
+ | {{toplink | ||
+ | |linkpage =Viruses | ||
+ | |linktext =VIRUSES | ||
+ | |sublink1=Retroviridae | ||
+ | |subtext1=RETROVIRIDAE | ||
+ | |pagetype =Bugs | ||
+ | }} | ||
+ | <br> | ||
+ | |||
+ | ====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 |
Revision as of 12:02, 23 May 2010
This article is still under construction. |
|
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