CONDITION
Bordetella in Cats
Bordetella is a bacterial infection of the airways caused by *Bordetella bronchiseptica*. The bacteria settle in the trachea and bronchi, triggering inflammation that leads to the respiratory signs an owner may observe. It is one of several infectious organisms that can contribute to upper respiratory disease in cats, particularly in environments where multiple cats live together. An owner most commonly notices sneezing, a harsh cough, nasal discharge, or noisy breathing. The signs often develop within a few days of exposure and typically last 7 to 10 days in otherwise healthy cats, though younger or stressed cats may experience more severe or prolonged illness. Some cats remain well but carry and shed the bacteria for several months after exposure, which means they can pass the infection to other cats even when they appear healthy. This page explores the signs that may prompt concern, what is happening in the airways during infection, how the condition is investigated, and the range of approaches that exist for managing it.
Why this matters now
Bordetella bronchiseptica tends to cause illness in settings where cats live in groups: shelters, catteries, breeding facilities, or multi-cat households. Young kittens are more likely to become seriously ill. Pneumonia is usually seen in kittens under 12 weeks old, although older cats can be affected. Stress, overcrowding, poor ventilation, and concurrent viral infections such as feline herpesvirus or calicivirus can all increase the likelihood that exposure will lead to clinical illness rather than silent carriage.
In most otherwise healthy adult cats, respiratory signs usually appear within a few days of exposure (2 to 6 days in experimental infections) and resolve over the course of 7 to 10 days without lasting complications. Young kittens and cats under high levels of stress carry a greater risk of the infection extending beyond the large airways into bronchopneumonia, which can bring laboured breathing, blue-tinged gums, and, in severe cases, death; this can get worse quickly, unlike the gradual course typical of adult cats. A proportion of cats, particularly those in shelter or cattery environments, will carry and shed the bacteria for weeks to months after signs have resolved, which means the infection can persist in a population even when individual animals appear well.
Signals & patterns
Early signals
Sneezing and nasal discharge
An owner may notice repeated sneezing and clear or cloudy discharge from one or both nostrils. The discharge can become thicker and more coloured over the first few days as inflammation develops in the nasal passages and sinuses.
Harsh, dry cough
Some cats develop a distinctive cough that sounds harsh or hacking, often described as though the cat is trying to clear something from the throat. This reflects irritation and inflammation in the trachea and larger airways where the bacteria have attached.
Noisy or rapid breathing
Breathing may become audible: wheezy, rattling, or congested, particularly during activity or sleep. The cat may also breathe faster than usual as the inflamed airways narrow and the effort of moving air increases.
Reduced appetite or quiet behaviour
A cat with upper respiratory infection may eat less or show less interest in normal activity. Nasal congestion reduces the ability to smell food, and the general discomfort of illness can lead to withdrawal or longer periods of rest.
Later signals
Persistent or worsening cough
In some cases the cough does not resolve within the first week or two, or it becomes more frequent and productive. This can indicate that inflammation has extended deeper into the bronchi or that secondary infection has developed.
Laboured breathing or open-mouth breathing
If the infection spreads to involve the smaller airways or lung tissue, the cat may begin to breathe with visible effort, using the chest and abdominal muscles more than usual, or may breathe with the mouth open, which is uncommon in cats and reflects significant respiratory distress.
Fever or lethargy
Some cats develop a fever, which may show as increased lethargy and reluctance to move. Fever indicates a more systemic response to infection.
Click to read about the biological mechanisms
How this is usually investigated
Investigation typically begins with a detailed history: recent exposure to other cats, the environment in which the cat lives, and the timeline of respiratory signs. Physical examination focuses on listening to the airways, assessing nasal discharge, and looking for signs of concurrent illness. When the clinical picture suggests bacterial involvement or when signs are severe or persistent, targeted tests may be used to confirm the organism and guide decisions about treatment and isolation.
Physical examination
Bacterial culture and sensitivity
Radiography
Polymerase chain reaction (PCR) testing
Options & trade-offs
Management is shaped by the severity of signs, the cat's age and immune status, and the setting in which the cat lives. Many otherwise healthy adult cats recover without specific treatment, but guidance favours antibiotics when *Bordetella* is thought to be causing the signs, with supportive care given alongside. The goal is to support the airways while the immune system clears the infection, reduce the risk of complications, and limit spread to other cats when relevant.
Supportive care
This involves keeping the cat comfortable and well-nourished while the infection runs its course. Measures include using a humidifier to ease airway congestion, encouraging appetite with palatable food, and ensuring the cat remains hydrated. Keeping stress low and avoiding exposure to smoke or strong fumes can reduce airway irritation.
Trade-offs: The European Advisory Board on Cat Diseases (ABCD) advises antibiotics when *Bordetella* is thought to be causing the signs, even when they are mild, because the infection can spread down into the lower airways. Supportive care is therefore usually given alongside treatment rather than instead of it. Cats that are not eating, are lethargic, or have laboured breathing may need more active intervention.
Antibiotic therapy
Antibiotics such as doxycycline are used when *Bordetella* is thought to be causing the signs, including mild cases, and matter most in young kittens or when there is concern about progression to pneumonia. Treatment typically lasts 7 to 10 days, and sometimes longer in chronic or slow-to-respond cases. The choice of antibiotic may be guided by culture and sensitivity results, particularly in catteries or shelters where resistant strains have been encountered.
Trade-offs: Antibiotics can reduce the severity and duration of clinical signs, but they may not stop the cat shedding the bacteria. Treating cats that have recovered but still carry the bacteria has little effect on shedding, so a treated cat may still be infectious to other cats. Doxycycline can cause oesophageal irritation in cats if tablets lodge in the throat, so giving it with food or water can reduce this risk. A liquid formulation can also help, but the doxycycline products authorised for cats in the UK are all tablets, so a liquid would be prescribed under the veterinary medicines cascade. Some cats are difficult to medicate, which can limit the practicality of a full course.
Isolation and environmental management
In multi-cat households, shelters, or catteries, isolating affected cats and improving ventilation, reducing crowding, and disinfecting surfaces can slow the spread of infection. *Bordetella* can survive in the environment for one to two weeks, so shared bowls, bedding and surfaces can spread it as well as direct contact and respiratory droplets. It is killed by common disinfectants, so physical separation and routine cleaning are used together.
Trade-offs: Isolation can be logistically challenging in busy environments and may increase stress in some cats, which can in turn prolong recovery or trigger shedding. Carrier cats, those that appear well but continue to shed bacteria, are difficult to identify without testing, so eliminating transmission entirely is often not achievable in practice.
Vaccination
An intranasal vaccine against *Bordetella bronchiseptica* has been used in high-risk settings such as shelters and boarding catteries. Its licence in Great Britain lapsed in October 2025, although it is still authorised in Northern Ireland, so it may not be available in Great Britain. It can be given from four weeks of age, at least 72 hours before the period of risk, and may reduce the severity of illness in cats that are later exposed. It is a live vaccine, so vaccinated cats can shed the vaccine strain for about six weeks and on and off for a year or more. It is not advised for cats that live with someone whose immune system is weakened.
Trade-offs: Vaccination does not prevent infection entirely and is most useful when given before exposure, so it is less relevant for cats already showing signs. Some cats sneeze or develop a mild, short-lived nasal discharge after receiving the intranasal vaccine. The vaccine is not part of routine core vaccination protocols and is usually considered only in situations where the risk of exposure is high.
Common misconceptions
"Bordetella only affects dogs, so a cough in a cat must be due to something else."
*Bordetella bronchiseptica* infects both dogs and cats. Cats can catch it from dogs with kennel cough, and living with a dog that has recently had a respiratory infection is a known risk factor. A harsh, persistent cough in a cat, particularly a young cat or one living in a group setting, can be caused by this bacterium, among other respiratory pathogens.
"If a cat is still coughing after a course of antibiotics, the treatment has failed and the infection is resistant."
A cough can take some time to settle after treatment, because the airway lining takes time to heal and inflammation can continue even as the infection is clearing. Some cats also carry the bacteria without active infection, so ongoing shedding does not always mean treatment failure. Culture and sensitivity testing can clarify whether resistance is present or whether the cough has another cause.
"Once a cat has recovered from Bordetella, it cannot become infected again."
It is not known how long immunity lasts after infection, so a cat that has recovered may not be protected if it is exposed again. Cats that have recovered may also remain carriers for weeks to months, shedding intermittently without showing signs, which means they can be a source of infection for other cats even when they appear well.
Related conditions
Feline Calicivirus
Feline calicivirus is another common cause of upper respiratory infection in cats, and it can occur alongside Bordetella bronchiseptica in multi-cat environments, producing overlapping signs of sneezing and nasal discharge. Calicivirus characteristically also causes oral ulceration, a feature not typical of Bordetella infection, so its presence points towards calicivirus, though laboratory testing may still be needed when the picture is mixed.
Feline Herpesvirus (FHV-1)
Feline herpesvirus type 1 is a frequent contributor to upper respiratory disease in cats and may co-infect with Bordetella bronchiseptica, particularly in settings where cats are housed together. Both organisms can trigger sneezing, nasal discharge, and eye inflammation, and infection with one may make the airways more susceptible to the other.
Chronic Upper Respiratory Disease in Cats
Chronic upper respiratory disease in cats can develop following acute infections with Bordetella or other respiratory pathogens, particularly when inflammation persists or when the cat becomes a carrier. Some cats continue to show intermittent sneezing or nasal discharge long after the initial infection has cleared.
Feline Asthma
Feline asthma can present with coughing and respiratory difficulty that may initially resemble the signs of Bordetella infection, particularly in cats with no prior history of airway disease. Distinguishing between an infectious cause and an allergic or inflammatory airway condition often requires examination of the pattern over time and response to different interventions.
Understanding how *Bordetella* fits into the broader picture of feline respiratory disease can be useful, particularly in multi-cat settings where several infectious organisms may be circulating at once. The page on Immune & Inflammatory Health explores how infection, environment, and immune function interact in cats. For cats with persistent cough or recurrent respiratory signs, conversations about the range of diagnostic options and the practical limits of testing in different settings can help clarify what is knowable and what remains uncertain in an individual case. Infection in people is rare. Most human cases are in people with a weakened immune system, and in a few of them a cat was suspected as the source; washing hands after handling a coughing cat is a reasonable precaution for the household. In a young kitten, breathing that becomes visibly laboured, or gums that look pale or blue-tinged, represents a different and faster-moving picture than the gradual, self-resolving course typical of adult cats.
Last reviewed: 9 October 2026 · Dr Alastair Greenway MRCVS