Feline Immunodeficiency Virus

Description

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

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

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

(FIV)