Feline Enteritis

“Feline enteritis” is one of those search terms people use when a cat has sudden vomiting and diarrhoea, or when a vet has mentioned a worrying virus and you’re trying to work out what it means, fast. Sometimes it’s a general label for inflammation of the gut. Sometimes it’s a specific, severe disease: feline panleukopenia (also called feline parvoviral enteritis or feline infectious enteritis), which can move quickly and be deadly in kittens.

Below is a clear way to tell those two situations apart, what signs matter most, how vets confirm a diagnosis, what treatment usually involves, and what prevention looks like in real homes and multi-cat settings.¹

What “feline enteritis” means (and why the wording matters)

Enteritis simply means inflammation of the small intestine. In everyday use, people often say “enteritis” when they mean gastroenteritis (stomach and intestines), which has many causes.

In veterinary medicine, the phrase feline enteritis is also commonly used to refer to feline panleukopenia virus (FPV) infection, a contagious parvovirus disease that targets rapidly dividing cells (including the gut lining and bone marrow). That’s the form most associated with severe dehydration, a low white blood cell count, and sudden collapse in unvaccinated kittens.^{1, 2}

The cause: panleukopenia (FPV) versus other gut upsets

When it’s feline panleukopenia (feline parvoviral enteritis)

Feline panleukopenia is caused by feline panleukopenia virus (a parvovirus). It spreads mainly by the faecal–oral route and via contaminated objects (bowls, bedding, hands, shoes). The virus is tough in the environment and can persist for long periods if cleaning and disinfection are poor.¹

When it’s “enteritis” in the broader sense

Many other problems can inflame a cat’s intestines and produce similar signs, including:

• Other infections (viral or bacterial)
• Intestinal parasites
• Dietary indiscretion (raiding rubbish, sudden diet changes)
• Pancreatitis, toxins, foreign bodies, chronic bowel disease (IBD) and other non-infectious causes

This is why the name alone isn’t enough. The same puddle of diarrhoea can come from very different stories.

Key signs and what they tend to look like

Typical signs of feline panleukopenia

FPV commonly causes some combination of:

• Sudden lethargy and marked depression
• Loss of appetite
• Fever
• Vomiting (often early)
• Diarrhoea (may be present and can be bloody, but is not guaranteed)
• Rapid dehydration

Kittens and unvaccinated young cats are affected most severely, and the illness can progress over just a few days. Sudden death can occur, particularly in very young kittens.^{2, 1}

Red flags that should prompt urgent veterinary care

• A kitten (or unvaccinated cat) with vomiting and/or diarrhoea plus profound lethargy
• Blood in vomit or stools
• Signs of dehydration (dry gums, sunken eyes, weakness, collapse)
• Repeated vomiting (can’t keep water down)
• Multiple cats in the home developing signs

How vets diagnose feline panleukopenia (and why tests can be tricky)

Vets usually combine the history (age, vaccination status, exposure risk) with an examination and targeted testing.

Common tests

• Blood tests (CBC): FPV often causes a very low white blood cell count (panleukopenia/leukopenia), reflecting bone marrow suppression.¹
• Point-of-care parvovirus antigen ELISA: in-clinic “snap” tests can support a diagnosis, but sensitivity is not perfect; a negative result does not reliably rule the disease out in a sick, high-risk cat.^{1, 6}
• PCR (laboratory testing): can be used to confirm infection, particularly when a rapid test is negative but suspicion remains high.⁶

False results: what to know

In shelters and clinics, canine parvovirus antigen tests are sometimes used to detect FPV because the viruses are closely related, and studies show they can detect FPV in feline samples. Interpretation still needs context and follow-up testing where needed.^{7, 6}

Recent vaccination with a modified-live core vaccine can, uncommonly, complicate interpretation of antigen testing in the short window after vaccination, which is one reason vets interpret results alongside clinical signs and may confirm with PCR.⁶

Treatment: what “supportive care” really means

There is no simple at-home cure for FPV. Treatment is largely supportive, aimed at keeping the cat alive and stable while the immune system clears the infection.

Depending on severity, supportive treatment may include:

• Intravenous fluids to correct dehydration and electrolyte imbalance
• Antiemetics (to control vomiting)
• Antimicrobials (to reduce the risk of secondary bacterial infection when white blood cells are low)
• Nutritional support once vomiting is controlled
• Parasite control where appropriate

Severely affected cats often need hospitalisation. Outcomes vary with age, vaccine status, and how quickly treatment starts.^{1, 2}

Home care and infection control (especially with more than one cat)

If your vet suspects FPV, managing the environment becomes part of the treatment plan. The goal is simple: reduce exposure for other cats and avoid re-infecting the recovering cat.

Practical steps that usually matter

• Isolate the sick cat from other cats if possible (separate room, separate bowls and litter tray).
• Limit traffic in and out of the isolation area. Use dedicated clothing or a washable cover-up.
• Clean first, then disinfect: organic matter (faeces, vomit) reduces the effectiveness of many disinfectants.
• Use a disinfectant proven against parvoviruses. Sodium hypochlorite (household bleach) is effective when used correctly, and published work supports its activity against feline panleukopenia virus under appropriate conditions.^{1, 8}

If you’re dealing with an outbreak risk (shelter, rescue, multi-cat household), your vet can advise on products and contact times appropriate for your surfaces and set-up. Avoid mixing cleaning chemicals.

Prevention: vaccination is the quiet workhorse

For panleukopenia, prevention is unusually solid: core vaccines are highly effective and widely recommended.

WSAVA vaccination guidelines describe panleukopenia (FPV) as a core feline vaccine. Kittens typically need a course of vaccinations starting around 8–9 weeks, repeated every 3–4 weeks, with a final dose at 16 weeks of age or older, followed by a booster 1 year later; subsequent boosters are generally no more frequent than every 3 years (depending on product and risk).³

Outbreaks still happen in communities with low vaccination coverage, and rescue/shelter environments can be higher risk because the virus spreads easily where many cats pass through.^{2, 4}

Complications and why the disease can turn severe

The most immediate danger is dehydration from vomiting and diarrhoea, compounded by electrolyte and blood-sugar disturbances. At the same time, FPV can suppress white blood cells, leaving the cat less able to contain secondary bacterial infections. In young kittens, the course can be abrupt.^{2, 1}

Frequently asked questions

Is feline enteritis always panleukopenia?

No. “Enteritis” just describes inflammation of the gut. Some people (and some clinic materials) use it as shorthand for panleukopenia, but many other conditions can cause enteritis-like signs. If panleukopenia is on the table, vaccination status and testing become urgent.¹

Can an indoor-only cat get panleukopenia?

Yes. FPV can be carried into the home on contaminated objects (shoes, clothing, carriers), and the virus is resilient in the environment. Indoor-only reduces risk, but does not eliminate it, which is why FPV is considered a core vaccine.^{1, 3}

If my cat survives, are they contagious?

Cats can shed virus around the time of illness, and hygiene and isolation instructions should come from your vet based on your cat’s situation and household risk. In multi-cat settings, assume careful infection control is needed until your vet clears the risk.¹

What’s the single most useful thing I can do right now?

If a cat (especially a kitten or unvaccinated cat) has vomiting/diarrhoea plus marked lethargy, treat it as urgent and contact a veterinarian. Early supportive care can be the difference between stabilising a cat and losing them to dehydration and complications.^{2, 1}

References

1. Merck Veterinary Manual (Professional) — Feline Panleukopenia (Feline Parvoviral Enteritis/Feline Infectious Enteritis)
2. Merck Veterinary Manual (Pet Owner) — Feline Panleukopenia
3. WSAVA Vaccination Guidelines — Feline vaccination recommendations (including FPV core vaccine)
4. RSPCA NSW — Protect Your Cat from Panleukopenia
5. ASPCApro — Feline Panleukopenia (shelter medicine guidance, diagnosis notes)
6. PubMed — Diagnostic testing for feline panleukopenia in a shelter setting (ELISA vs PCR; interpretation)
7. PubMed — Detection of feline panleukopenia virus using a commercial ELISA for canine parvovirus
8. PubMed — Virucidal disinfectants and feline viruses (sodium hypochlorite efficacy against FPV)