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Feline Immunodeficiency Virus (FIV)

A lentivirus (similar to HIV in humans) that progressively weakens the cat's immune system. Cats can live many healthy years with FIV before becoming immunocompromised. NOT transmissible to humans.

Last updated: 2026-05-09

Severity

moderate

When to Act

See Vet Soon

Symptoms & Signs

Often asymptomatic for years

Most FIV-positive cats appear completely healthy initially — sometimes for 5-10+ years after infection.

Always present

Stomatitis/gingivitis

Severe oral inflammation is one of the most common clinical signs.

Very common

Recurrent infections

Bacterial, fungal, and parasitic infections that are more severe or harder to treat than in FIV-negative cats.

Very common

Weight loss

Progressive wasting as the immune system deteriorates.

Sometimes occurs

Neurological signs

Behavioral changes, dementia, neuropathy in advanced stages.

Rarely occurs

Behavioral Changes to Watch For

Pets can't tell us what's wrong. These behavioral changes are often the first clues that something is wrong.

🐾 Increased aggression (intact males)

FIV is primarily transmitted through deep bite wounds — intact males that roam and fight are at highest risk.

What You May Notice:

Your outdoor male cat comes home with fight wounds — this is the highest-risk behavior for FIV transmission.

Causes & Risk Factors

Causes

  • •Infection with feline immunodeficiency virus (FIV) — a lentivirus
  • •Transmitted primarily through deep bite wounds (saliva-to-blood)
  • •Less commonly: vertical transmission from queen to kittens (less efficient than FeLV)
  • •Unlike FeLV, casual contact (grooming, sharing bowls) is a very low-risk route

Risk Factors

  • ⚠Intact outdoor male cats (highest risk — roaming and fighting)
  • ⚠Stray and feral cats
  • ⚠Multi-cat households with inter-cat aggression

How It's Diagnosed

  • 1In-clinic ELISA (SNAP FIV test) — detects antibodies
  • 2Kittens from FIV-positive queens may test positive from maternal antibodies — re-test at 6 months
  • 3PCR testing available but has high false-negative rate
  • 4A positive antibody test in a low-risk (indoor, altered) cat should be confirmed with another method

Treatment Options

lifestyle

Proactive Healthcare Management

FIV-positive cats can live long, healthy lives with excellent care.

Steps

  1. 1.Indoor-only lifestyle — protects the cat from pathogens AND prevents transmission to other cats
  2. 2.High-quality nutrition
  3. 3.Prompt and aggressive treatment of any infections
  4. 4.Regular veterinary check-ups every 6 months
  5. 5.Dental care is especially important
  6. 6.Spay/neuter to reduce roaming and fighting

Expected Outcome

FIV-positive cats often live normal lifespans with good care, dying from age-related causes rather than FIV/AIDS.

Precautions

  • !FIV-positive cats can coexist peacefully with FIV-negative cats if there is no fighting
  • !Separate during introductions and any tension

Common Medications Used

MedicationUsageImportant Notes

Prevention

  • ✓Keep cats indoors or provide supervised outdoor access (catio, leash walks)
  • ✓Spay/neuter — reduces roaming and fighting behavior
  • ✓Test new cats before integrating into the household
  • ✓FIV vaccine exists but is not recommended by most experts (interferes with testing, variable efficacy)

When to See a Veterinarian

  • ⚠️Any infection that doesn't resolve with standard treatment
  • ⚠️Oral inflammation, bleeding gums
  • ⚠️Weight loss
  • ⚠️Any new cat before household introduction (testing)

Frequently Asked Questions

Can I catch HIV/AIDS from my FIV-positive cat?
No. FIV is species-specific — it cannot infect humans. It is a lentivirus that only infects felines. Similarly, HIV cannot infect cats. The two viruses are related but distinct. There is no risk of FIV transmission from cats to humans, including immunocompromised individuals.

Prognosis

Generally good. The virus itself is slowly progressive — most cats live 5-10+ years after diagnosis with appropriate care. They typically die from secondary diseases facilitated by immunosuppression rather than FIV directly. Many FIV-positive cats live full, normal lifespans.

References

  • [1] AAFP — FIV Management Guidelines
  • [2] Cornell Feline Health Center

📝 Related Articles

Cat Health

Indoor vs. Outdoor Cats: Health Risks, Lifespan, and the Data

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