Feline Immunodeficiency Virus

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Also known as: FIV

Description

Agent

Transmission and Epidemiology

Feline Immunodeficiency Virus is commonly abbreviated to FIV

  • Unrelated to HIV
  • No vaccinal protection between USA Petulama prototype and UK (Hayling Island) isolate
  • Cats, including large cats on game reserves
  • 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

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
        • Skin infections
        • Usually followed by secondary infection as a result of immunosuppression
        • Virus-ridden T cell destroy normal T cells, causing chronic immunosuppression


Diagnosis

Clinical Signs

Laboratory Tests

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

Pathology

Control

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


(FIV)

  • Lentivirus
  • Subtypes A, B and D
  • Causes increased susceptibility to infections and neoplasia
  • Specifically destroys CD4+ T cells
  • Virus is present in saliva, blood and other bodily fluids
  • Feral and outdoor cats (mostly tom cats) are most at risk
  • Virus replicates in lymphoid tissue
  • Can remain asymptomatic
  • Causes pyrexia and lymphadenopathy
  • Transmitted by biting
  • Diagnosis:
    • ELISA
    • Rapid-Immuno-Migration
    • Western Blot
    • Virus Isolation
    • Immunofluorescence
    • PCR
  • Treatment:
    • Antibiotics for secondary infection
    • Anti-retroviral therapy
  • For vaccinations see here