Diagnosing Feline AIDS: FIV in Cats

Diagnosing feline AIDS, a chronic, debilitating illness that can end in death, may be a difficult call due to the complexity of the infection. FIV disables your cat's immune system, rendering it unable to fend off bacteria, fungi, parasites and viruses. Cats with FIV may die from opportunistic infections. No cure exists for FIV, though your cat may live more than a decade with the infection. The sooner a correct diagnosis is made, the sooner treatment can begin.

How Your Cat Contracts FIV

An infected mother cat can pass on FIV to her kittens during birth or nursing. FIV can also spread through contact with infected blood and saliva when fighting cats bite and scratch each other.

Symptoms of Feline AIDS

  • Low white cell count
  • High globulin count
  • Fever
  • Fatigue
  • Diarrhea
  • Vomiting
  • Anemia
  • Anorexia
  • Weight loss
  • Swollen lymph nodes
  • Mouth, tooth and gum disease  
  • Depression
  • Dementia

How the Vet Checks for FIV

The vet assesses risk factors. One risk factor is that cats living outdoors are more vulnerable to attacks by other infected cats. Another risk factor is that unsterilized male cats tend to fight more, increasing their exposure to FIV through lacerations to the skin.

The vet documents symptoms of FIV, which usually manifest in three main stages:

  1. Acute stage. Six weeks after contracting FIV, your cat may experience the following symptoms: fever and swollen lymph glands.
  2. Latent stage. For several years after FIV infection, your cat may exhibit virtually no serious symptoms. However, internally, the virus slowly devastates the immune system as it disseminates throughout your cat's body.
  3. Final stage. Your cat's immune system is now effectively destroyed, allowing opportunistic illnesses to set in, including respiratory infections, pneumonia, anemia, skin disease, lymphoma, gastrointestinal disease and mouth infections. Your cat will probably not survive this stage.

The vet will administer a simple blood test to check for the presence of FIV antibodies. Interpreting FIV blood test results conclusively, however, may prove difficult. Positive results may be incorrect. In turn, negative results may also be incorrect.

FIV Test Results Are Categorized:

  • Positive, possibly indicating your cat is infected and will be a carrier for life. However, since false-positive results occur, your vet will retest your cat again in 8 to 12 weeks. Also with a positive result, your cat will undergo further medical testing to assess the stage and severity of the disease.  
  • Indeterminate, or "equivocal," possibly indicating a condition of the blood that interferes with the test. Your vet will likely choose to retest at a later date.
  • Negative, usually indicating your cat is not infected with FIV. However, since FIV antibodies take two to three months after an infection to appear in a blood sample, false negatives may also occur. Your vet may decide to retest an antibody-negative cat after the usual incubation period.

Why Kittens Should Be Tested for FIV

FIV spreads from mother to kitten through breast milk, making testing for the virus as early as possible extremely important. A positive result may not be conclusive, however, as the test may identify the mother's antibodies, still present in the kitten's body. Kittens testing antibody-positive shortly after birth should then be retested after six months of age, when only its own antibodies remain in the blood.