Difference between revisions of "Feline Immunodeficiency Virus"

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*Infected cats develop antibody whether or not they are able to clear the virus
 
*Infected cats develop antibody whether or not they are able to clear the virus
 
Two versions:
 
Two versions:
*Avirulent:
+
*'''Avirulent''':
 
**Transient infection with no CD4 decline
 
**Transient infection with no CD4 decline
*Virulent:
+
*'''Virulent''':
 
**Progressive CD4 decline with three stages (may present indistinct)
 
**Progressive CD4 decline with three stages (may present indistinct)
 
**#'''High circulating virus''' for 1-10 weeks with resulting lymphoid depletion and CD8CD4 double positive Tcell destruction, '''thymic aplasia''' esp in kittens
 
**#'''High circulating virus''' for 1-10 weeks with resulting lymphoid depletion and CD8CD4 double positive Tcell destruction, '''thymic aplasia''' esp in kittens
 
**#'''Remission''': decrease in circulating virus as immune response increases, followed by '''immune exhaustion'''
 
**#'''Remission''': decrease in circulating virus as immune response increases, followed by '''immune exhaustion'''
****Increase in CD8+ production and antibody response
+
**#*Increase in CD8+ production and antibody response
****Paracortical T cells and lymphoid follicles expand in primary and secondary lymph tissue and may be visible as '''white nodules'''
+
**#*Paracortical T cells and lymphoid follicles expand in primary and secondary lymph tissue and may be visible as '''white nodules'''
 
**#'''Rapidly progressing infection''' with high virus present  
 
**#'''Rapidly progressing infection''' with high virus present  
****Feline AIDS presents in a minority of cases
+
**#*Feline AIDS presents in a minority of cases
****Nonregenerative anemia
+
**#*Nonregenerative anemia
****Leucopenia
+
**#*Leucopenia
****Neutropenia
+
**#*Neutropenia
****Usually followed by secondary infection as a result of '''immunosuppression'''
+
**#*Usually followed by secondary infection as a result of '''immunosuppression'''
****Virus-ridden T cell destroy normal T cells, causing chronic immunosuppression
+
**#*Virus-ridden T cell destroy normal T cells, causing chronic immunosuppression
  
 
====Epidemiology====
 
====Epidemiology====

Revision as of 18:55, 20 October 2008



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VIRUSES
RETROVIRIDAE



Antigenicity

  • Unrelated to HIV
  • No vaccinal protection between USA Petulama prototype and UK (Hayling Island) isolate

Hosts

  • Cats, including large cats on game reserves

Pathogenesis

  • Receptor: CD134, found on monocyte-derived macrophages and activated T cells
    • Net effect: disruption of acquired immune response
  • Infected cats develop antibody whether or not they are able to clear the virus

Two versions:

  • Avirulent:
    • Transient infection with no CD4 decline
  • Virulent:
    • Progressive CD4 decline with three stages (may present indistinct)
      1. High circulating virus for 1-10 weeks with resulting lymphoid depletion and CD8CD4 double positive Tcell destruction, thymic aplasia esp in kittens
      2. Remission: decrease in circulating virus as immune response increases, followed by immune exhaustion
        • Increase in CD8+ production and antibody response
        • Paracortical T cells and lymphoid follicles expand in primary and secondary lymph tissue and may be visible as white nodules
      3. Rapidly progressing infection with high virus present
        • Feline AIDS presents in a minority of cases
        • Nonregenerative anemia
        • Leucopenia
        • Neutropenia
        • Usually followed by secondary infection as a result of immunosuppression
        • Virus-ridden T cell destroy normal T cells, causing chronic immunosuppression

Epidemiology

  • Transfer via saliva, though usually through a bite (FIV is the disease of enemies)
  • Can transfer via milk or mutual grooming in multicat households
  • Also transferred via mating
  • Particular concern amongst stray males: 3.5% of healthy UK cats are seropositive, but in stray toms, up to 10% are positive
  • Four-fold more common in diseased cats than in healthy cats

Diagnosis

  • ELISA for serum antibody
    • False positives occur, particularly in the presence of maternal Ab
  • Positives can be confirmed by lab work (Western blotting)

Control

  • No UK vaccine
  • Healthy positive cats should have diagnose confirmed by further testing
  • Isolate and castrate
  • Preventative neutering of males