Feline Influenza and Cat Flu: Symptoms, Treatment & Prevention
Feline influenza, commonly referred to as cat flu, is one of the most frequent respiratory illnesses affecting cats in the UK. While healthy adult cats often recover with veterinary care and time, elderly cats, young kittens, and those with compromised immune systems are particularly vulnerable and can suffer severe consequences. Unlike the mild flu in humans, feline influenza can be serious and sometimes fatal in cats. Fortunately, vaccination against the main causes of cat flu is typically included in your cat’s annual booster, though it doesn’t offer complete protection.
All cat owners should be aware of feline influenza’s nature, symptoms, transmission, and treatment to safeguard their pets and identify the illness early.
What is feline influenza and how does it differ from “cat flu”?
Feline influenza refers to respiratory infections in cats caused by certain influenza A viruses. However, these are relatively rare in cats. The term "cat flu" more commonly describes a feline upper respiratory infection syndrome caused mainly by two non-influenza viruses: feline herpesvirus (FHV-1) and feline calicivirus (FCV).
Other agents such as Bordetella bronchiseptica and Chlamydia felis may sometimes contribute to the illness.
| Aspect | Feline Influenza Virus Infection | Cat Flu (Common Feline URI) |
|---|---|---|
| Cause | Rare influenza A viruses | Feline herpesvirus and calicivirus (non-influenza) |
| Frequency | Rare | Common |
| Symptoms | Upper respiratory signs, occasionally severe systemic illness | Sneezing, nasal and eye discharge, conjunctivitis, lethargy, loss of appetite |
| Contagiousness | Highly contagious among vertebrates | Highly contagious among cats |
| Transmission | Respiratory droplets and contact | Contact with saliva, tears, contaminated objects |
| Carrier Status | Possible, severity varies | Cats may become lifelong carriers |
| Human Transmission | Generally none | No |
| Vaccination | Not commonly part of standard cat vaccines | Recommended for prevention |
Causes and Vaccination Effectiveness
Over 80% of typical cat flu cases are caused by the viruses feline herpesvirus and calicivirus, both of which are included in standard annual vaccinations. These vaccines can significantly reduce the risk and severity of infection, but they do not cover all possible pathogens causing cat flu. About 20% of infections may be due to other viruses or bacteria not covered by vaccination, so a vaccinated cat is reduced in risk but not fully immune.
How is cat flu transmitted among cats?
Cat flu is highly contagious and spreads easily from cat to cat. Transmission occurs via direct contact with infected cats or through airborne particles released by coughing and sneezing. The viruses can also survive on shared items such as bedding, food and water bowls, and even on humans, making it possible for cats to contract the illness without direct physical contact with an infected cat.
Some cats may carry the virus without showing any symptoms, acting as carriers who can transmit the infection to others.
Recognising the Symptoms of Cat Flu
Signs of feline influenza and cat flu include:
- Sneezing
- Nasally congested, noisy or raspy breathing
- Runny eyes and nose
- Sore throat indicated by raspiness or changes in meows
- Dribbling
- Lethargy and subdued behaviour
- Fever or high temperature
- Loss of appetite
The severity can vary with the viral strain. Feline herpesvirus infections often result in more severe illness, including eye ulcers, thick mucky discharge, and swollen eyes that may close shut. Feline calicivirus usually causes milder symptoms but risks mouth ulcers, lameness, and high fever if untreated.
Treatment and Care for Cats with Feline Influenza
There is currently no cure for cat flu, and treatment primarily involves supportive care to help your cat recover. Intensive nursing and comfort are crucial to improving their chances of defeating the infection.
Common treatment measures include:
- Ensuring hydration with water or intravenous fluids if necessary
- Encouraging eating with tasty food, or IV feeding if they won’t eat
- Keeping essentials like litter trays, food, and water close to minimise movement
- Providing warmth and a comfortable resting place
- Cleaning discharge from eyes and nose gently
- Using steam inhalation to ease breathing
- Antibiotics to treat secondary bacterial infections
- Antiviral medications in some cases as prescribed by your vet
- Practising barrier nursing to prevent spread to other cats
Outlook for Cats with Cat Flu / Feline Influenza
Healthy adult cats usually recover fully with prompt care, though recovery can take several weeks. Many veterinary insurers cover treatment costs if vaccinations are up to date.
Cats infected with feline herpesvirus may remain lifelong carriers and can intermittently shed the virus, posing a risk to other cats. Feline calicivirus infections usually clear from the system but can take weeks to months in some cases.
Early detection, vaccination, and good hygiene are key to protecting your feline companion from this common and potentially serious disease.