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 7–10 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. Kittens and young cats are more frequently affected than adults, in part because their immune systems are still developing and in part because they are more likely to be in high-density environments during the early weeks of life. 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 appear within two to ten days of exposure and resolve over the course of seven to fourteen days without lasting complications. Kittens, immunosuppressed cats, and those with pre-existing airway disease may experience more severe or prolonged illness, and in some cases the infection can progress to involve the lower airways or lead to secondary bacterial pneumonia. 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 be noticed as warmth to the touch, particularly at the ears, or 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

Purpose: Listening to the trachea and chest can reveal harsh airway sounds, wheezing, or crackles that suggest inflammation or mucus in the airways. The pattern of nasal discharge, the presence of fever, and the cat's overall demeanour help distinguish upper respiratory infection from pneumonia or other systemic illness.
Considerations: The findings are often non-specific; many respiratory pathogens produce similar signs. A normal examination does not rule out infection, particularly in the early stages or in cats that are carriers without active illness.

Bacterial culture and sensitivity

Purpose: A swab taken from the nasopharynx or trachea and submitted for culture can identify *Bordetella bronchiseptica* and determine which antibiotics the organism is sensitive to. This is the most direct way to confirm the bacteria are present.
Considerations: Collection requires sedation or anaesthesia in many cats to reach the trachea, and results take several days. A negative culture does not definitively exclude infection, because shedding can be intermittent and sampling technique affects yield. The test is most useful when the diagnosis will change management—such as in a cattery outbreak or in a cat with severe or recurrent signs.

Radiography

Purpose: Chest radiographs show whether the infection has extended into the lower airways or lung tissue, revealing patterns of bronchial thickening or patchy infiltrates that suggest bronchopneumonia.
Considerations: Radiographs are typically reserved for cats with persistent cough, laboured breathing, or systemic signs such as lethargy and inappetence. Mild upper airway infection often produces normal chest films, and the findings do not identify the specific pathogen.

Polymerase chain reaction (PCR) testing

Purpose: PCR detects *Bordetella bronchiseptica* DNA in respiratory samples and can identify the organism more rapidly and sensitively than culture. It is often performed as part of a respiratory panel that screens for multiple viral and bacterial pathogens simultaneously.
Considerations: PCR tells you the organism is present but does not distinguish between active infection and asymptomatic carriage. It also does not provide antibiotic sensitivity information, so culture may still be needed if treatment is not responding as expected.

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, while younger or more severely affected cats may benefit from antibiotics or supportive care. 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: Supportive care alone may be sufficient for mild cases in healthy adults, but it does not shorten the duration of illness or eliminate bacterial shedding. Cats that are not eating, are lethargic, or have laboured breathing may need more active intervention.

Antibiotic therapy

Antibiotics such as doxycycline are often used in cats with moderate to severe signs, in young kittens, or when there is concern about progression to pneumonia. Treatment typically lasts 7–14 days. 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 and may shorten the period of bacterial shedding, though they do not always eliminate carriage entirely. Doxycycline can cause oesophageal irritation in cats if tablets lodge in the throat, so giving it with food or water and ensuring the cat swallows fully is important. 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* survives poorly in the environment but spreads readily through direct contact and respiratory droplets, so physical separation and hygiene measures are more effective than surface disinfection alone.

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* is available and may be used in high-risk environments such as shelters or boarding facilities. The vaccine is typically given to kittens from four weeks of age and may reduce the severity of illness and the duration of shedding in cats that are subsequently exposed.

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 mild nasal discharge for a few days 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

Misconception:

"Bordetella only affects dogs, so a cough in a cat must be due to something else."

Reality:

*Bordetella bronchiseptica* infects both dogs and cats, and transmission between the two species can occur, though cat-to-cat spread is more common in practice. 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.

Misconception:

"If a cat is still coughing after a course of antibiotics, the treatment has failed and the infection is resistant."

Reality:

A cough can persist for days to weeks after the bacterial load has been reduced, 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.

Misconception:

"Once a cat has recovered from Bordetella, it cannot become infected again."

Reality:

Infection does not confer lasting immunity, and cats can be re-infected if exposed again, particularly in environments where the bacteria circulate continuously. 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, nasal discharge, and oral ulceration. Distinguishing between the two often requires laboratory testing, as the clinical picture may be similar.

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.

Chronic Bronchitis in Dogs

Chronic bronchitis in dogs shares a pattern of airway inflammation and cough with Bordetella infection in cats, though the underlying drivers and typical species affected differ. Both conditions involve damage to the lining of the bronchi and may produce a persistent, harsh cough that prompts investigation.

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.

Last reviewed: 12 September 2026 · Dr Alastair Greenway MRCVS