What Causes Feline Rhinotracheitis (Cat Flu)?

Disease Prevention πŸ“… August 6, 2026 πŸ‘ 1762

πŸ“ Summary

Cat flu (feline rhinotracheitis) is caused by herpesvirus dormant in nerve cells that flares under stress or poor nutrition, plus calicivirus, chlamydia, mycoplasma and Bordetella. It is not contagious to people but a recovered cat carries the virus for life. Symptoms overlap between agents, so veterinary diagnosis is essential for correct treatment.

1 What Is Cat Flu?

New cats often show sneezing, nasal discharge, red swollen eyes and ocular/nasal discharge a few days after arriving home. The herpesvirus that causes it sleeps in nerve cells and erupts under stress or poor nutrition – which is why a healthy breeder cat falls ill at a new home. Cat flu does not infect people, but a recovered cat carries the virus for life and can spread it for months, so think carefully before adding a new cat.

2 The Infection Sources

While feline herpesvirus causes most cases, cat flu is not herpes alone. Viral agents include feline calicivirus; non-viral agents include chlamydia, mycoplasma and Bordetella. All can trigger the syndrome.

3 Symptoms by Agent

Herpes: fever, sneezing, nasal discharge, weepy inflamed eyes, sometimes mouth ulcers. Calicivirus: similar signs plus frequent mouth ulcers and joint pain. Chlamydia: fever, sneezing, weepy eyes, swollen lymph nodes. Mycoplasma: weepy eyes, swollen lymph nodes, anemia. Bordetella: fever, sneezing, nasal discharge, cough, weepy eyes, possible lymph swelling. See a vet for an accurate diagnosis and treatment.

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