FIV in Cats: Feline Immunodeficiency Virus Explained
- FIV is a lifelong viral infection that weakens immune defenses over time, but many FIV-positive cats stay well for years and may have near-normal lifespans with regular monitoring.
- It spreads mainly through deep bite wounds from cat fights, so casual contact like sharing bowls, grooming, or using the same litter box is considered low risk in stable households.
- A positive screening test is often followed by confirmatory testing, especially in low-risk cats, recently exposed cats, or kittens with possible maternal antibodies.
- Most care focuses on prevention and early treatment: indoor living, routine exams every 6 months, parasite control, dental care, balanced nutrition, and prompt attention to infections.
- See your vet promptly if your cat has mouth pain, weight loss, chronic sneezing, diarrhea, fever, swollen lymph nodes, poor coat quality, or wounds that heal slowly.
What Is FIV (Feline Immunodeficiency Virus)?
Feline immunodeficiency virus, or FIV, is a lentivirus in the retrovirus family that infects cats and targets important immune cells. Over time, this can reduce the body’s ability to respond to infections, inflammation, and some cancers. FIV is species-specific, which means it does not infect people, dogs, or other non-feline pets.
One of the most important things for pet parents to know is that an FIV-positive result is not a hopeless diagnosis. Many cats remain symptom-free for long periods, and some never develop severe illness. With indoor living, regular checkups, good dental care, balanced nutrition, and prompt treatment when problems appear, many FIV-positive cats enjoy a good quality of life for years.
FIV does not usually make a cat sick overnight. Instead, it tends to act slowly. A cat may go through an early phase with mild fever or enlarged lymph nodes, then appear completely normal for months or years. Later, if immune function declines, secondary infections and inflammatory conditions become more likely.
Because the course of disease varies so much, the goal is not to predict one exact outcome. It is to work with your vet on a care plan that matches your cat’s age, symptoms, home environment, and overall health.
Symptoms of FIV in Cats
- No symptoms for months to years after infection; many cats appear completely healthy during the long latent phase
- Recurring respiratory, skin, ear, or urinary infections that seem to come back or take longer to clear
- Severe gingivitis or stomatitis causing bad breath, drooling, pawing at the mouth, or trouble eating
- Weight loss or muscle loss, especially if paired with reduced appetite or chronic inflammation
- Chronic diarrhea or poor stool quality that lasts more than a few days
- Poor coat condition, dandruff, or reduced grooming
- Enlarged lymph nodes, especially under the jaw or behind the knees
- Eye inflammation such as redness, squinting, cloudiness, or vision changes
- Slow wound healing, persistent skin sores, or abscesses after fights
- Less common neurologic changes such as behavior shifts, weakness, disorientation, or seizures
Many FIV-positive cats feel normal for a long time, so the first clues are often secondary problems rather than the virus itself. Repeated infections, mouth pain, weight loss, and poor healing matter more than one isolated sneeze or one soft stool.
See your vet sooner rather than later if symptoms are recurring, lasting more than a few days, or affecting eating, drinking, breathing, comfort, or energy. See your vet immediately if your cat cannot eat because of mouth pain, is struggling to breathe, has a high fever, seems suddenly weak, or has a bite wound with swelling or drainage.
How Do Cats Get FIV?
FIV spreads primarily through saliva introduced by deep bite wounds. That is why the highest-risk cats are typically intact or previously intact males, outdoor cats, and cats with a history of fighting. Casual contact is much less efficient for transmission.
In most homes, sharing food bowls, water bowls, litter boxes, and resting spaces is considered low risk, especially when cats get along and do not fight. Mutual grooming is also thought to be a much less common route than biting. This is why some mixed FIV-positive and FIV-negative households can work, but the decision depends on the personalities of the cats and the risk of aggression.
Transmission from a mother cat to kittens can happen, but it is considered uncommon compared with bite-wound spread. The virus is also fragile outside the body, so it does not persist well in the environment. Routine household cleaning is enough; FIV is not a virus that lingers in the home the way some hardier pathogens can.
If your cat has been in a fight, especially with an unknown outdoor cat, ask your vet whether testing now and retesting later makes sense. Recently infected cats can test negative before antibodies become detectable.
How Is FIV Diagnosed?
FIV is usually diagnosed with a blood antibody test, often an in-clinic ELISA or SNAP-style screening test. These tests look for the cat’s immune response to the virus rather than the virus itself. A positive result often means infection, but context matters.
Your vet may recommend confirmatory testing if the result does not fit the cat’s history, if the cat is low risk, or if there is any question about accuracy. This is especially important because recently infected cats may test negative at first, while kittens can test positive because of maternal antibodies they received from an infected mother.
Kittens with a positive result are often retested when they are older, commonly around 6 months of age, because maternal antibodies can fade over time. Cats tested very soon after a bite exposure may also need repeat testing several weeks later if the first result is negative.
A positive FIV test is only one part of the picture. Your vet may also recommend a physical exam, complete blood count, chemistry panel, urinalysis, FeLV testing, and dental evaluation to look for anemia, inflammation, kidney issues, oral disease, or other conditions that affect day-to-day management.
Treatment Options for FIV-Positive Cats
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Conservative
- In-clinic FIV screening test and follow-up confirmatory testing if needed
- Baseline exam with focused history on fighting, appetite, weight, and dental comfort
- Indoor-only or securely contained lifestyle to reduce exposure and prevent bite transmission
- Balanced commercial diet and avoidance of raw meat, raw eggs, and unpasteurized dairy
- Prompt treatment of minor infections, wounds, or abscesses when they appear
- Routine parasite control and at least twice-yearly wellness visits
Standard
- Semiannual exams with weight tracking and oral health checks
- Baseline and periodic lab work such as CBC, chemistry panel, urinalysis, and FeLV testing if status is unknown
- Dental cleaning and dental imaging when indicated for gingivitis, stomatitis, or tooth root disease
- Targeted treatment for secondary infections, including antibiotics, pain control, fluids, or supportive care as needed
- Individualized vaccine review based on lifestyle and risk
- Nutrition review, body condition monitoring, and parasite prevention plan
Advanced
- Referral-level dentistry for severe stomatitis, including multiple extractions or full-mouth extraction when appropriate
- Advanced imaging, biopsy, or specialist workup for chronic weight loss, masses, eye disease, or neurologic signs
- Oncology or internal medicine consultation if lymphoma, immune-mediated disease, or complex chronic infection is suspected
- Hospitalization for dehydration, severe infection, or inability to eat
- Longer-term pain management and nutrition support for cats with significant oral disease or chronic inflammatory complications
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About FIV
Bring these questions to your vet appointment to get the most out of your visit.
- Do you recommend confirmatory testing for my cat’s positive or negative result, and when should that be done? Timing matters after recent exposure, and kittens or low-risk cats may need follow-up testing for a clearer answer.
- How often should my cat have exams, blood work, and urinalysis now that they are FIV-positive? Monitoring schedules vary by age, symptoms, and overall health, and a clear plan helps you catch changes early.
- Can my FIV-positive cat safely live with my other cats in this specific household? The answer depends less on bowl sharing and more on whether the cats are stable, bonded, and unlikely to fight.
- What signs of mouth disease or stomatitis should I watch for at home? Oral inflammation is common in FIV-positive cats and can affect comfort, appetite, and weight before it becomes obvious.
- Which vaccines, parasite prevention products, and routine screenings do you recommend for my cat’s lifestyle? Preventive care still matters, but the plan should be individualized rather than one-size-fits-all.
- If my cat gets sick, when is home monitoring reasonable and when should I come in right away? FIV-positive cats may need earlier treatment for infections, wounds, fever, or appetite loss.
- What is the likely cost range for routine FIV monitoring versus dental care or treatment if complications develop? Understanding likely costs helps you plan for both expected care and possible flare-ups.
How to Prevent FIV
The most effective way to prevent FIV is to reduce the chance of cat fights and bite wounds. For most pet parents, that means keeping cats indoors or in a secure outdoor enclosure, and neutering cats who might otherwise roam or fight.
Testing matters too. If you are adopting a new cat or bringing a cat into a multi-cat household, ask your vet about FIV and FeLV testing before introductions. This is especially helpful when the new cat has an unknown history, has lived outdoors, or has visible scars from previous fights.
There is no commercially available FIV vaccine in North America today, so prevention relies on lifestyle and screening rather than vaccination. If you already have an FIV-positive cat, prevention shifts toward protecting that cat from avoidable infections: indoor living, routine dental care, parasite control, balanced nutrition, and prompt veterinary attention when symptoms appear.
An FIV-positive diagnosis should not automatically rule out adoption. Many FIV-positive cats are affectionate, stable companions who can do very well in the right home. The key is matching the home setup to the cat’s health and behavior, then building a realistic care plan with your vet.