Is FIP or FIV Contagious to Other Cats?

Name: Is FIP or FIV Contagious to Other Cats?
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

FIP in cats contagious to other cats? The short answer is no, not in the way most people fear. Feline infectious peritonitis itself does not pass from cat to cat, but the common coronavirus that can lead to it does spread easily between cats. FIV is different. It spreads mainly through deep bite wounds, so casual contact between friendly housemates is a low risk. This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

FIP is not spread directly from one cat to another. It develops when a common feline coronavirus already living in a cat mutates inside that individual cat [1].
The coronavirus that can lead to FIP is contagious between cats, mostly through feces and litter box contact, but most infected cats never develop FIP [1][2].
FIV spreads mainly through saliva delivered by bite wounds, not through shared bowls, grooming, or sneezing [3][4].
Cats in stable, non-fighting households are at little risk of catching FIV from an infected housemate [3].
If any cat in your home has a new diagnosis, talk to your veterinarian about testing and separating resources before you make big changes.

What FIP and FIV Actually Are

These two diseases get grouped together because both have "feline" in the name and both can make cats very sick. Beyond that, they are completely different problems caused by different viruses.

FIP is a severe disease caused by a feline coronavirus [1]. Coronaviruses are a family of viruses that mostly cause respiratory or intestinal infections. Many cats carry a feline coronavirus in their gut without any serious trouble. In a small number of cats, the virus changes and the cat's immune response goes the wrong way, and the result is FIP [1]. FIP is most common in cats 6 months to 2 years old, though cats of any age can develop it [1]. Purebred cats, including Persians, Abyssinians, Bengals, Birmans, Himalayans, Ragdolls, and Rex breeds, are more likely to be affected [1].

FIV attacks the immune system. Infected cats may look completely normal for months or years, but over time the immune system weakens and everyday bacteria, viruses, and fungi can cause serious illness [3]. Cats with FIV also have a higher risk of certain blood cancers [4]. Once a cat is infected, it stays infected for life [4]. The good news is that many FIV-positive cats live average life spans if they are not also infected with feline leukemia virus [3].

If you want a deeper look at the disease itself, see FIP in Cats: Symptoms, Diagnosis, and How It Is Treated Today.

Is FIP in Cats Contagious to Other Cats?

This is the question that worries multi-cat owners most, and the answer has two layers.

FIP itself is not contagious. A cat with FIP does not shed the mutated virus in a way that infects housemates with FIP [1]. You cannot catch FIP from your cat, and your other cats cannot catch FIP directly from a cat that has it.

The coronavirus behind FIP is contagious. Feline coronavirus spreads readily among cats, especially in groups. Kittens raised in infected colonies can pick up the virus from their mothers or from carriers (infected cats with no obvious signs) when maternal immunity drops at 5 to 6 weeks of age [1]. The virus is common worldwide, and a large number of cats may be infected without ever developing the severe form of the disease [1]. Only a few of those cats go on to develop FIP, and it is not fully understood why. A mutation within the virus plus an inappropriate immune response in that individual cat are thought to be responsible [1].

So the practical takeaway is this. If one of your cats has FIP, your other cats are not at risk of catching FIP from that cat. They may already carry their own feline coronavirus, which is extremely common. Whether any of them develops FIP depends on their own immune response, not on contact with the sick cat.

Is FIV in Cats Contagious to Other Cats?

FIV is contagious, but it is not easy to catch. The primary route is bite wounds from an infected cat [3]. The virus lives in saliva, and it takes a deep bite to move it from one cat into another cat's tissues [4].

Casual, non-aggressive contact does not appear to spread FIV efficiently. Sharing water bowls, mutual grooming, and living in the same space are not considered effective routes of transmission [3]. Cats in households with stable social structures, where housemates do not fight, are at little risk of acquiring FIV from each other [3]. Sexual contact is not a significant means of spread among cats [3].

There is one important exception. On rare occasions, an infected mother cat can pass FIV to her kittens. If the mother becomes infected during pregnancy, the risk to the kittens goes up [3].

Cats that roam outdoors, male cats, and older cats are more likely to become infected [4]. That pattern fits the bite-wound route, since roaming and fighting go together.

How FIP and FIV Spread: A Side-by-Side Look

Feature	FIP	FIV
What causes it	Feline coronavirus that mutates in an individual cat [1]	Feline immunodeficiency virus [3]
Does the disease itself spread cat to cat	No [1]	Yes, but mainly by bite wounds [3]
Main transmission route	The coronavirus spreads between cats, often through feces and shared litter areas [1]	Saliva entering a bite wound [3][4]
Risk from shared bowls or grooming	Coronavirus can spread in group settings, FIP cannot [1]	Low risk with casual contact [3]
Risk from fighting	Not a factor for FIP itself	High, this is the main route [3]
Mother to kitten	Possible with coronavirus in infected colonies [1]	Rare, higher if the mother is infected during pregnancy [3]
Who is most at risk	Cats 6 months to 2 years, some purebreds [1]	Outdoor cats, male cats, older cats [4]

Signs Owners Notice

FIP signs can be vague at first. Cats may have a fever, lose weight, stop eating well, or just seem off. Some cats develop fluid in the belly or chest, and others have eye or neurologic problems. Because the signs are not specific, diagnosis is genuinely difficult, and veterinarians rely on a combination of lab tests, history, and clinical signs to improve accuracy [2].

FIV often looks like nothing at all early on. Shortly after infection, a cat may have a fever and enlarged lymph nodes, but those signs go away and the cat can appear healthy for months or years [4]. Later, FIV-positive cats are more likely to get infections affecting the gums, mouth, digestive tract, urinary tract, and skin [4].

If your cat has been sneezing or has nasal discharge, that is usually a separate issue from FIP or FIV. Two articles that cover those signs are Cat Sneezing a Lot: Allergies, Infection, or Something Else? and Why Is My Cat sneezing with blood? Upper Respiratory Infection and Nasal Polyps.

Causes and Risk Factors

For FIP, the risk factors are age, breed, and environment. Cats between 6 months and 2 years old are affected most often, and certain purebreds are overrepresented [1]. Living in a crowded group with a lot of coronavirus circulating raises the chance that a cat will be exposed to the virus in the first place [1].

For FIV, the risk factors are behavioral. Cats that go outdoors, male cats, and older cats are more likely to be infected [4]. A stable, indoor, non-fighting household is the lowest-risk setting [3].

One more thing worth knowing is that cats can carry more than one infection at once. In a group of 100 cats diagnosed with FIP, coinfections included feline calicivirus in 27 cats, feline foamy virus in 22, feline herpesvirus in 6, FIV in 4, and feline leukemia virus in 2 [5]. That does not mean one caused the other. It means testing for multiple infections can matter when a cat is sick.

How These Conditions Are Diagnosed

FIP diagnosis is a puzzle. Veterinarians combine laboratory tests, the cat's history, and clinical signs because no single test gives a clean yes or no [2]. Newer tools are being studied, including a serum exosomal miRNA signature that showed promise as a non-invasive early diagnostic marker in one analysis [6]. Genetic studies continue to examine specific mutations in the virus, such as M1058L and S1060A in the spike protein, though their exact role in causing disease is still debated [7].

FIV diagnosis is more straightforward. A veterinarian will typically start with a screening test and may confirm with a different method. If you want to understand the difference between rapid in-clinic tests and laboratory testing, this article explains it: Feline Leukemia FeLV and FIV Testing: Snap Tests vs PCR Differences.

Treatment Options

FIP used to be considered fatal, and euthanasia was commonly recommended after diagnosis [8]. That has changed. Antiviral therapies, especially nucleoside analogues such as oral GS-441524, have made FIP a treatable and frequently curable disease [8]. GS-441524 is the most extensively studied antiviral for FIP, with treatment success rates often exceeding 90% [8]. Remdesivir is primarily reserved for specific situations, and other antivirals such as molnupiravir are also part of the discussion, though availability varies around the world [8].

Cats that also carry a retrovirus can still do well with treatment. In one survey of 17 cats positive for feline leukemia virus or FIV and treated with GS-441524 for effusive FIP, the 12-week survival rate was 94% and the one-year survival rate was 82% [9]. Treatment was adjusted in many of those cats, with the starting dosage increased in 65% and treatment extended in 35% [9]. That is a decision your veterinarian makes based on the individual cat.

Newer options are being studied too. One experimental antiviral, VV116, improved survival to 75% in infected cats and reduced viral loads in most organs in a research setting [10]. It is not a standard treatment today, but it shows where the field is heading.

FIV has no cure [3]. Treatment focuses on managing secondary infections, dental disease, and other problems as they come up. Your veterinarian will calculate any medication dose from your cat's weight and health status.

Recovery, Outlook, and Long-Term Management

For FIP, the outlook is far better than it was a decade ago. With antiviral treatment, many cats recover, though some relapse and some need longer or higher-dose therapy [8][9]. Follow-up monitoring matters, and your veterinarian will set a schedule for rechecks.

For FIV, the outlook can still be good. Cats with FIV commonly live average life spans as long as they are not also infected with feline leukemia virus [3]. Long-term care means regular veterinary visits, attention to dental health, and prompt treatment of any new infection [4].

In a multi-cat home, long-term management is mostly about reducing stress and preventing fights. Stable social groups are the goal, since that is what keeps FIV risk low [3].

Prevention

There is no effective vaccine for FIP, and no definitive cure, which is why prevention focuses on reducing coronavirus spread in groups [2]. Keeping litter boxes clean, avoiding overcrowding, and limiting exposure to cats outside your home all help lower the amount of virus circulating.

For FIV, prevention is about behavior. Keeping cats indoors and preventing bite wounds is the most direct step, since roaming and fighting drive transmission [3][4]. If you bring a new cat into the home, test before introductions and give the cats time to adjust with separate resources at first.

If you are managing wounds or skin issues in a multi-cat home, do not reach for human antiseptics without checking first. This article covers one common question: Can You Use Povidone Iodine On Cats.

Limitations and When to Contact a Veterinarian

No article can tell you what is happening with your specific cat. Individual cases need a veterinarian who can examine the cat, review the history, and run the right tests.

Contact your veterinarian the same day if your cat stops eating, has a fever that will not go away, is losing weight, or has new swelling in the belly or chest.

Go to an emergency clinic now if your cat is struggling to breathe, collapsing, having seizures, or cannot stand.

Schedule a routine visit if you are planning to add a cat to the household, if a housemate was recently diagnosed with FIV or FIP, or if you have not had your cats tested and you want a clear baseline.

Frequently Asked Questions

Can I catch FIP or FIV from my cat?

No. Neither FIP nor FIV infects people. These viruses are specific to cats, so you do not need to worry about household transmission to humans.

Should I separate my cats if one has FIP?

Separation is not needed to prevent FIP itself, because FIP does not pass directly between cats [1]. However, the coronavirus that can lead to FIP does spread in groups, so good litter box hygiene and reduced crowding are still smart. Ask your veterinarian what fits your household.

Can two FIV-positive cats live together safely?

Yes, generally they can. FIV spreads mainly through bite wounds, and cats in stable households that do not fight are at little risk of passing it to each other [3]. The main concern is stress and fighting, so introductions should be gradual.

Do I need to re-test my other cats after one is diagnosed?

It depends on which disease and what your veterinarian recommends. Testing is most useful when there has been a bite wound or a new cat entered the home. Your veterinarian can decide which cats need testing and when.

Is FIP always fatal?

No, not anymore. FIP was once considered fatal, but antiviral treatment with drugs such as GS-441524 has changed the outlook, with success rates often above 90% [8]. Early diagnosis and prompt treatment give the best chance of a good outcome.

References

Feline Infectious Peritonitis (FIP) - Cat Owners. Merck Veterinary Manual.
Feline Infectious Peritonitis: A Challenging Diagnostic and Therapeutic Labyrinth. Animals : an open access journal from MDPI, 2026.
Feline Immunodeficiency Virus (FIV). Cornell University College of Veterinary Medicine.
Feline Immunodeficiency Virus (FIV) - Cat Owners. Merck Veterinary Manual.
Viral Coinfections Potentially Associated with Feline Chronic Gingivostomatitis in Cats with Feline Infectious Peritonitis. Viruses, 2025.
The value of serum exosomal miRNA signature profiles for the early diagnosis of feline infectious peritonitis. Experimental biology and medicine (Maywood, N.J.), 2026.
Single-site mutation (M1058L) of feline infectious peritonitis virus (FIPV) spike protein in domestic cats of Northern Vietnam. Archives of virology, 2026.
Update on Treatment of Feline Infectious Peritonitis: European Advisory Board on Cat Diseases (ABCD) Guidelines. Viruses, 2026.
Clinical Features and Outcomes of Treatment for Effusive Feline Infectious Peritonitis with GS-441524 in Seventeen Retrovirus-Positive Cats. Pathogens (Basel, Switzerland), 2026.
VV116 exerts potent efficacy against feline infectious peritonitis. Veterinary microbiology, 2026.