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Created page with "Feline Leukemia Virus is commonly abbreviated to FeLV ====Antigenicity==== *Main envelope protein: gp70 *3 antigenic subgroups: *Group A **is transmitted between cats **is mono..."
Feline Leukemia Virus is commonly abbreviated to FeLV
====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
(FeLV)
[[Image:FeLV Electron Micrograph.jpg|thumb|right|150px|FeLV Electron Micrograph [http://phil.cdc.gov/phil/home.asp Public Health Image Library] Image #5610]]
[[Image:Kinetics of FeLV 2.jpg|thumb|right|150px|Kinetics of FeLV - Copyright Dr Brian Catchpole BVetMed PhD MRCVS]]
*Oncogenic retrovirus
*Causes neoplasia (lymphoma), myelosuppression (anaemia) and immunosuppression (of [[Lymphocytes#T cells|T cells]])
*2 strains:
**FeLV-A
***Natural strain
**FeLV-B
***Formed through FeLV-A recombining with endogenous retroviral sequences in the feline genome
***Increases the risks of lymphoma
**FeLV-C
***Formed from the spontaneous mutation of FeLV-A
***Is more myelosuppressive
*Virus replicates in the oropharyngeal lymphoid tissue causing a viraemia (virus circulating in the bloodstream) which then spreads to the systemic lymphoid tissue
*Shed in saliva
*Passed by oronasal route, e.g. mutual grooming
*Kittens between 6 weeks and 6 months are most susceptible
*60% of cats will become immune to the disease and recover
*Cats that are persistently viraemic will progress to develop FeLV-associated diseases
*Some cats will become viraemic again if treated with corticosteroids or stressed if the infection lies dormant in the [[Bone Marrow - Anatomy & Physiology|bone marrow]]
*Diagnosis:
**ELISA
**Rapid-Immuno-Migration
**Western Blot
**Virus Isolation
**Immunofluorescence
**PCR
*Treatment:
**Antibiotics for secondary infection
**Anti-retroviral therapy
*For vaccinations see [[Vaccines - WikiBlood#Cat Vaccinations|here]]
[[Category:Mammalian Type C retrovirus ]][[Category:Cat]][[Category:Secondary Immunodeficiency]]
[[Category:To_Do_-_Clinical/Viruses]]
[[Category:To Do - Blood]][[Category:Lymphoreticular and Haemopoietic Diseases]]
====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
(FeLV)
[[Image:FeLV Electron Micrograph.jpg|thumb|right|150px|FeLV Electron Micrograph [http://phil.cdc.gov/phil/home.asp Public Health Image Library] Image #5610]]
[[Image:Kinetics of FeLV 2.jpg|thumb|right|150px|Kinetics of FeLV - Copyright Dr Brian Catchpole BVetMed PhD MRCVS]]
*Oncogenic retrovirus
*Causes neoplasia (lymphoma), myelosuppression (anaemia) and immunosuppression (of [[Lymphocytes#T cells|T cells]])
*2 strains:
**FeLV-A
***Natural strain
**FeLV-B
***Formed through FeLV-A recombining with endogenous retroviral sequences in the feline genome
***Increases the risks of lymphoma
**FeLV-C
***Formed from the spontaneous mutation of FeLV-A
***Is more myelosuppressive
*Virus replicates in the oropharyngeal lymphoid tissue causing a viraemia (virus circulating in the bloodstream) which then spreads to the systemic lymphoid tissue
*Shed in saliva
*Passed by oronasal route, e.g. mutual grooming
*Kittens between 6 weeks and 6 months are most susceptible
*60% of cats will become immune to the disease and recover
*Cats that are persistently viraemic will progress to develop FeLV-associated diseases
*Some cats will become viraemic again if treated with corticosteroids or stressed if the infection lies dormant in the [[Bone Marrow - Anatomy & Physiology|bone marrow]]
*Diagnosis:
**ELISA
**Rapid-Immuno-Migration
**Western Blot
**Virus Isolation
**Immunofluorescence
**PCR
*Treatment:
**Antibiotics for secondary infection
**Anti-retroviral therapy
*For vaccinations see [[Vaccines - WikiBlood#Cat Vaccinations|here]]
[[Category:Mammalian Type C retrovirus ]][[Category:Cat]][[Category:Secondary Immunodeficiency]]
[[Category:To_Do_-_Clinical/Viruses]]
[[Category:To Do - Blood]][[Category:Lymphoreticular and Haemopoietic Diseases]]