Moderate severity

Bordetella Infection

A bacterial respiratory infection that spreads rapidly wherever cats are housed together. Mild in most adults, genuinely dangerous in young kittens, where it can descend into pneumonia.

⚠️ Common symptoms

Sneezing and clear nasal discharge, becoming thickerCoughing — less common in cats than dogs, but a strong clue when presentFever and reduced appetiteWatery eyesEnlarged lymph nodes under the jawRapid or laboured breathing in severe casesSudden death in very young kittens, occasionally with few warning signs

Where It Fits Among Cat Flu

Most upper respiratory disease in cats is viral, and feline herpesvirus and calicivirus between them account for the great majority of what owners call cat flu. Bordetella is the bacterial member of the group, and it matters for three reasons: it spreads extremely efficiently in groups, it can cause primary disease rather than merely complicating a viral infection, and in kittens it has a genuine tendency to move down into the lungs.

Because the signs overlap almost completely with the viral causes, Bordetella is rarely distinguished on appearance. It is identified by culture or PCR from a swab, and in practice that testing is usually done when an outbreak is being investigated rather than for an individual sniffly cat.

The Kitten Problem

In adult cats this is typically an unpleasant fortnight. In kittens under about three months, particularly those in crowded or stressful conditions, it can produce a rapidly progressive bronchopneumonia with a real mortality rate. Litters have been lost in shelters to this organism. Any kitten that is breathing quickly, breathing with visible effort, or has gone quiet and stopped nursing needs veterinary assessment the same day — the window in which supportive treatment works is short.

The Zoonotic Question

Bordetella bronchiseptica can, very rarely, infect people. Healthy adults are effectively not at risk, and the handful of documented human cases have almost all involved significant immunosuppression — transplant recipients, people with advanced HIV, those on chemotherapy. If somebody in the household is in that position, ordinary sensible hygiene is worth observing around an infected cat: wash hands, avoid face-to-face contact, and mention the pet's diagnosis to their doctor. For everybody else it is not a practical concern.

Managing an Outbreak

If several cats in a group start sneezing, act on the group rather than the individual. Isolate affected cats, improve ventilation before reaching for disinfectant, clean bowls and litter trays separately, and change clothing between groups. Bordetella is susceptible to routine disinfectants and does not survive long in the environment, so the transmission that keeps an outbreak running is nearly always via hands and shared equipment rather than the building itself.

🔍 Causes

Bordetella bronchiseptica is the same organism responsible for much of what is called kennel cough in dogs, and it infects cats readily. It is spread by direct contact, by aerosolised droplets from sneezing, and on contaminated hands, bowls, bedding and clothing. The bacterium attaches to the cilia lining the airway and disables the mechanism that clears mucus and debris, which is why secondary infections follow so easily. Crowding, poor ventilation, and the stress of rehoming all raise both the infection rate and the severity, which is why shelters, breeding catteries, boarding facilities and rescue situations see it most. Cross-infection between dogs and cats in the same household is documented and reasonably common.

🛡 Prevention

In a home with one or two settled cats, no specific measures are needed beyond ordinary hygiene. In multi-cat environments, the interventions that work are unglamorous: good ventilation, lower stocking density, separating new arrivals for a fortnight, and washing hands between cats. An intranasal Bordetella vaccine for cats exists and is used selectively — it is not part of routine vaccination for a pet cat, but it is worth discussing for cats entering shelters, breeding colonies, or boarding facilities with a history of outbreaks. If a household dog has kennel cough, keep it away from kittens and from any cat that is immunosuppressed.

💊 Treatment

Most otherwise healthy adult cats recover with supportive care alone: warmth, encouragement to eat strongly aromatic food, steam from a bathroom to loosen nasal congestion, and gentle cleaning of discharge from the nose and eyes. Where treatment is indicated, doxycycline is the usual first-line antibiotic and is generally given for one to three weeks — it should be followed by water or food to prevent oesophageal irritation, which is a real risk with tablet forms in cats. Kittens or adults showing signs of lower airway disease need more: hospitalisation, intravenous fluids, oxygen and nebulisation may all be required, since bronchopneumonia in a young kitten can progress within hours. Antibiotics should be chosen on the basis of culture where an outbreak is being managed in a shelter or breeding colony.

When to see a vet: Any kitten with respiratory signs should be seen promptly rather than watched, since deterioration can be fast. Book an appointment for an adult cat whose sneezing persists beyond a few days, whose discharge turns thick or coloured, or that stops eating — a cat that cannot smell its food frequently stops eating altogether, and that brings its own dangers. Go urgently for laboured or open-mouth breathing, blue-tinged gums, or marked lethargy.

⚕️ Medical disclaimer

  • This information is educational only and is not a substitute for veterinary advice.
  • Symptoms overlap between conditions — only a vet can diagnose accurately.
  • Never withhold treatment or self-medicate based on information found online.
  • When in doubt, call your vet. Early intervention almost always leads to better outcomes.

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