Pasteurellosis in Rabbits
TL;DR. Pasteurellosis, or 'snuffles,' is a highly contagious bacterial infection in rabbits that causes respiratory issues, eye discharge, and abscesses, requiring long-term veterinary management due to its tendency to recur.
A clean, well-ventilated environment is essential for preventing and managing pasteurellosis in rabbits.
What is it?
Pasteurellosis is a highly contagious bacterial infection in rabbits caused by the bacterium Pasteurella multocida. Among rabbit owners and breeders, this condition is frequently referred to as 'snuffles' due to the characteristic wet, snuffly breathing sounds affected rabbits make. While it is one of the most common infectious diseases diagnosed in domestic rabbits, it is also one of the most complex and persistent.
To understand this disease, it is helpful to understand how a rabbit's respiratory system works. Rabbits are obligate nasal breathers, meaning they must breathe through their noses. Any inflammation, swelling, or accumulation of mucus in the nasal passages significantly compromises their ability to breathe. Pasteurella multocida primarily colonizes the upper respiratory tract, specifically the nasal cavity and sinuses.
However, this bacterium is opportunistic and highly invasive. If a rabbit's immune system is compromised or stressed, the bacteria can easily migrate to other parts of the body. This can lead to a multi-systemic disease. The bacteria can travel down into the lungs to cause pneumonia, move through the eustachian tubes into the middle and inner ear, migrate into the tear ducts and eyes, or enter the bloodstream to cause deep-tissue abscesses and life-threatening septicemia (blood poisoning).
The anatomical connection between the nasal passages, eyes, and ears allows Pasteurella to spread easily.
Causes & risk factors
The primary cause of pasteurellosis is the transmission of Pasteurella multocida bacteria. This transmission occurs rapidly through direct contact between rabbits, inhalation of airborne droplets generated by sneezing, or contact with contaminated surfaces such as food bowls, water bottles, and bedding.
Many rabbits are subclinical carriers of the bacteria. This means they harbor Pasteurella multocida in their nasal passages without showing any outward signs of illness. The bacteria can remain dormant for months or even years, kept in check by the rabbit's immune system. However, certain triggers can disrupt this balance, allowing the bacteria to multiply rapidly and cause active disease. These risk factors include:
- Environmental stress: Sudden temperature fluctuations, drafts, high humidity, or poor ventilation.
- Poor sanitation: A buildup of ammonia from accumulated urine in the litter box or cage. Ammonia gas is highly irritating to the delicate linings of the rabbit's nasal passages, making it easier for bacteria to invade.
- Overcrowding: Housing too many rabbits together increases stress levels and facilitates the rapid spread of pathogens.
- Nutritional deficiencies: A diet lacking high-quality grass hay and essential nutrients weakens the immune system.
- Co-existing illness: Other underlying health issues, such as dental disease or parasitic infections, drain the rabbit's physical resources.
There are no documented breed predispositions for pasteurellosis. Any breed of domestic rabbit, from the smallest dwarf to the largest giant, is equally susceptible to contracting the infection if exposed and stressed.
Signs to watch for
The clinical signs of pasteurellosis can vary widely depending on which organ systems the bacteria have invaded. Because rabbits are prey animals, they instinctively hide signs of illness until they are severely compromised. Owners must observe their pets closely for subtle changes.
- Sneezing (Cardinal): Frequent, wet sneezing fits are often the first sign of upper respiratory involvement.
- Mucopurulent nasal discharge (Cardinal): A thick, sticky, white-to-yellow mucus discharging from the nostrils. In healthy rabbits, the nose should be dry and clean.
- Conjunctivitis (Common): Redness, swelling, and watery or pus-like discharge from one or both eyes. This occurs when the bacteria travel up the nasolacrimal (tear) ducts.
- Matted fur on the forepaws (Common): Because rabbits groom their faces constantly, they will use their front paws to wipe away nasal and ocular discharge. Wet, matted, or crusty fur on the inside of the front legs is a classic sign of 'snuffles' even if you do not see active nasal discharge.
- Head tilt (Occasional): Also known as 'wryneck,' a head tilt occurs when the infection spreads into the middle or inner ear (otitis media or interna), disrupting the rabbit's sense of balance.
- Dyspnea (Occasional): Labored, heavy, or open-mouth breathing. Because rabbits are obligate nasal breathers, open-mouth breathing is a severe, life-threatening emergency indicating that the lungs are compromised (pneumonia) or the nasal passages are completely blocked.
- Subcutaneous abscesses (Occasional): Firm, pain-free or tender lumps under the skin. Rabbit pus is extremely thick and caseous (resembling toothpaste), meaning these abscesses do not drain easily on their own.
Matted fur on the forepaws is a classic sign of 'snuffles' caused by grooming nasal discharge.
How vets diagnose it
Diagnosing pasteurellosis requires a thorough physical examination and targeted diagnostic testing. Because other pathogens (such as Bordetella bronchiseptica or Pseudomonas) and non-infectious issues (such as dental disease) can cause similar respiratory signs, accurate testing is vital.
Your vet will likely recommend the following diagnostic steps:
- Deep nasal swab culture and sensitivity [GOLD STANDARD]: To perform this test accurately, the vet must insert a sterile swab deep into the nasal cavity, often requiring mild sedation to prevent injury to the rabbit's delicate nasal turbinates. A simple shallow swab of the outer nostril is rarely useful, as it primarily collects harmless environmental bacteria. The collected sample is sent to a laboratory to grow the bacteria and identify the specific strain of Pasteurella multocida. Crucially, the 'sensitivity' portion of the test determines which specific antibiotics will be most effective at killing that particular strain.
- PCR (Polymerase Chain Reaction) for Pasteurella multocida: This highly sensitive molecular test detects the DNA of the bacteria. It is exceptionally useful for identifying the pathogen even if the bacteria are present in low numbers or if the rabbit has already started antibiotic therapy, which can interfere with traditional cultures.
- Skull radiographs (X-rays): If your rabbit exhibits a head tilt, chronic nasal discharge, or suspected dental issues, skull radiographs are essential. X-rays allow the vet to evaluate the middle ears (tympanic bullae) for fluid accumulation or bone destruction. They also allow for the assessment of the tooth roots; because rabbit teeth grow continuously, overgrown tooth roots can impinge on the tear ducts and nasal passages, mimicking or exacerbating pasteurellosis.
Skull radiographs help veterinarians evaluate the middle ears and tooth roots for signs of deep infection.
Treatment options
Treating pasteurellosis is challenging and requires a prolonged course of targeted antibiotic therapy. Because rabbits have a highly specialized and delicate digestive system, choosing the correct antibiotic and route of administration is a matter of life and death.
First-Line Therapies
- Enrofloxacin (Fluoroquinolone Antibiotic): This is one of the most commonly prescribed broad-spectrum antibiotics for rabbits. It is well-tolerated, penetrates tissues effectively, and can be administered orally or via injection.
- Sulfadiazine/Trimethoprim and Sulfamethoxazole/Trimethoprim (Potentiated Sulfonamide Antimicrobials): These oral antibiotics are highly effective against many bacterial respiratory pathogens. They are generally safe for the rabbit's gastrointestinal tract and are often selected for long-term management.
Second-Line Therapies
- Penicillin G (Natural Penicillin Antibiotic): Penicillin G is highly effective against Pasteurella multocida, but it carries a critical safety warning. Penicillin G must only be administered via subcutaneous injection (parenterally).
CRITICAL SAFETY WARNING: Never administer penicillin or related antibiotics (like amoxicillin or ampicillin) orally to a rabbit. Oral administration destroys the beneficial Gram-positive bacteria in the rabbit's cecum, leading to a rapid, fatal overgrowth of toxin-producing bacteria (a condition known as enterotoxemia or gut dysbiosis).
Supportive Care
In addition to antibiotics, supportive care is vital to help your rabbit recover:
- Nebulization: Using a pediatric nebulizer with saline solution (and sometimes prescribed antibiotics or bronchodilators) helps loosen thick mucus in the nasal passages, allowing the rabbit to breathe more easily.
- Anti-inflammatory medications: Non-steroidal anti-inflammatory drugs (NSAIDs) may be prescribed to reduce pain and inflammation in the nasal passages or ears.
- Nutritional support: If your rabbit's appetite decreases, syringe-feeding a high-fiber recovery formula is critical to prevent gastrointestinal stasis (a life-threatening shutdown of the digestive tract).
Prognosis
The long-term prognosis for rabbits diagnosed with pasteurellosis is guarded to fair.
While veterinary treatment can successfully resolve active clinical signs (such as sneezing, runny eyes, and lethargy), completely eradicating Pasteurella multocida from the rabbit's respiratory tract is incredibly difficult. The bacteria often retreat deep into the nasal turbinates, middle ear, or encapsulated abscesses where antibiotics cannot easily reach them.
Consequently, many rabbits become chronic carriers. They may remain healthy and symptom-free for long periods, but the infection can recur during times of physical or emotional stress. Managing pasteurellosis is often a lifelong commitment to maintaining an optimal environment and monitoring your rabbit closely for the first signs of a flare-up.
Prevention
Because Pasteurella multocida is highly contagious and difficult to eliminate once established, prevention is the most effective tool for protecting your rabbit.
- Quarantine protocols: Always isolate any new rabbit brought into your home for a minimum of four weeks. Monitor the new rabbit closely for any signs of sneezing, eye discharge, or matted paws before introducing them to your existing rabbits.
- Optimize ventilation: Ensure your rabbit's living area is well-ventilated. Avoid solid-walled glass tanks or plastic cages, which trap ammonia fumes and moisture. Wire-sided enclosures or open-pen setups are highly preferred.
- Rigorous hygiene: Clean litter boxes daily to prevent the buildup of ammonia. Wash food bowls and water bottles regularly.
- Stress reduction: Keep your rabbit's routine as consistent as possible. Provide plenty of hiding spaces, a balanced diet consisting of unlimited grass hay, fresh leafy greens, and a limited amount of high-quality pellets.
- Avoid sudden environmental changes: Protect your rabbit from extreme temperature changes, drafts, and damp conditions.
When to call your vet
You should schedule a veterinary appointment if you notice any mild signs of respiratory distress, such as occasional sneezing, clear nasal discharge, or slightly watery eyes.
Seek immediate emergency veterinary care if your rabbit exhibits any of the following red-flag signs:
- Labored breathing, wheezing, or open-mouth breathing
- A sudden, severe head tilt
- Complete loss of appetite (anorexia) lasting more than 12 hours
- Extreme lethargy or inability to stand
- Blue or pale gums and tongue
Sources
Because specific textbook citations were not provided in the source record, the clinical guidance in this article is based on standard-of-care veterinary consensus and established clinical protocols for exotic companion mammal medicine.
