CATS · Condition guide
Cat flu (feline URI): real veterinary cases
Cat flu — formally feline upper respiratory tract infection (URI) — is the most common infectious disease in cats, especially in kittens, multi-cat households, shelters, and any cat under stress. The main culprits are feline herpesvirus type 1 (FHV-1) and feline calicivirus (FCV), with Chlamydia felis and Bordetella playing smaller roles. Classic signs are sneezing, ocular and nasal discharge, conjunctivitis, mouth ulcers (especially FCV), and reduced appetite.
Most cats recover with supportive care — fluids, appetite stimulants, and warm humidified air — but FHV-1 establishes lifelong latent infection and can reactivate under stress, causing recurrent flare-ups. Severe cases benefit from oral famciclovir for FHV-1 or doxycycline for Chlamydia. Cats with chronic stomatitis or persistent ocular ulceration deserve specialist workup.
What vets typically check for
- Clinical signs are usually enough; PCR (oropharyngeal swab) confirms viral aetiology when needed.
- Fluorescein staining of the eye to detect dendritic ulcers (pathognomonic for FHV-1).
- Supportive care: fluids, syringe-feeding, steam therapy, regular eye/nose cleaning.
- Antivirals: oral famciclovir for severe FHV-1; topical cidofovir for ocular disease.
- Doxycycline for suspected Chlamydia (mucopurulent conjunctivitis).
Not a replacement for veterinary care. Use this to walk into the conversation prepared, not to self-diagnose.
Real cases from the veterinary literature
Peer-reviewed reports our semantic search surfaces for Feline upper respiratory infection (cat flu). Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- Molecular investigation of feline herpesvirus 1 (fhv-1) and feline calicivirus in cats with respiratory system problem
Eurasian Journal of Veterinary Sciences · TR
A group of cats with respiratory problems were tested for two common viruses, feline herpesvirus 1 (FHV-1) and feline calicivirus (FCV). Out of 70 cats showing symptoms, 33 tested positive for FHV-1 and 7 for FCV, with some having both infections. The study found that FHV-1 was more prevalent in cats with respiratory issues. To help prevent these infections and reduce symptoms,
- First report of fatal feline pulmonary tuberculosis caused by the emerging zoonotic pathogen Mycobacterium orygis in a cat from India.
Veterinary research communications · 2026 · India
A 5-month-old stray domestic shorthair cat in India was brought to the vet in severe shock and struggling to breathe. X-rays showed serious lung issues, and tests revealed the presence of a dangerous bacteria called Mycobacterium orygis, which is known to cause tuberculosis. Unfortunately, despite the efforts to diagnose and treat the cat, it passed away within 24 hours. This c
- Evaluation of amyloid A and haptoglobin in the serum of cats with respiratory diseases.
Frontiers in veterinary science · 2026 · Germany
A group of cats with respiratory issues were tested for two proteins, amyloid A and haptoglobin, to see if they could help identify specific diseases. The study found that cats with infections in their lower airways had higher levels of amyloid A compared to those with other respiratory conditions. However, all protein levels were still within normal ranges. Haptoglobin levels
- Lapachol, a dihydroorotate dehydrogenase inhibitor, demonstrates antiviral activity against feline calicivirus in vitro and in vivo.
Antiviral research · 2026 · China
A group of cats infected with feline calicivirus (FCV) showed symptoms like respiratory issues and oral ulcers. Researchers tested a compound called lapachol and found that it significantly reduced the virus in their bodies when given orally. The cats not only shed less virus but also recovered from weight loss and improved their overall health without any harmful side effects.
- Clinical and Laboratory Findings in Cats with Confirmed Avian Influenza A/H5N1 Virus Infection During the 2023 Outbreak in Poland: A Retrospective Case Series of 22 Cats.
Pathogens (Basel, Switzerland) · 2026
A group of 22 domestic cats in Poland were diagnosed with avian influenza A/H5N1 in June 2023, showing symptoms like fever, lethargy, and loss of appetite that quickly progressed to severe breathing problems and neurological issues such as seizures and difficulty walking. Tragically, all the affected cats died or were euthanized within three days of showing symptoms. Many of th
- Sinonasalin a cat with comorbidities.
The Canadian veterinary journal = La revue veterinaire canadienne · 2026 · Canada
A 15-year-old spayed female domestic shorthair cat was brought in for a swollen area over her right eye that turned into an open wound. Despite trying various antibiotics, the wound didn't heal, and tests showed she had a rare infection in her nasal cavities. The vet started her on a specific antibiotic treatment that helped improve her symptoms, but it didn't completely cure t
Frequently asked questions
- Is cat flu contagious to other cats?
- Yes — extremely. Spread by direct contact, sneezed droplets, and shared bowls/litter. Quarantine new arrivals for at least 2 weeks. The viruses are easily killed by household disinfectants but can survive in the environment for days.
- Can I catch it from my cat?
- No. Feline herpesvirus and calicivirus are species-specific. Chlamydia felis is also extremely unlikely to infect humans. Wash hands after handling sick cats as basic hygiene, but you don't need to worry about getting cat flu yourself.
- Will the vaccine prevent it?
- Core vaccines (FVRCP) reduce severity but don't fully prevent infection — once a cat catches FHV-1, the virus stays for life and can flare during stress. Vaccination remains strongly recommended; the goal is mild rather than no disease.