Respiratory Bacterial Infection in Rabbits

Pasteurellosis in Rabbits

Infection with the Pasteurella multocida bacterium can result in a severe respiratory illness, generally characterized by nose infections, sinusitis, ear infections, conjunctivitis, pneumonia, and generalized infection of the blood, among other things. This condition is often referred to as the “snuffles” because of the snuffling breathing sound affected rabbits make. It may also cause abscesses in the subcutaneous (beneath the top layer of skin) tissues, bone, joints, or internal organs in rabbits. The pasteurella bacteria usually co-exist in the rabbit’s body with other, more common bacteria that cause nasal infections.

In rabbits with strong immune systems, these bacteria can reside in the nasal cavity and upper respiratory tract, and are kept in check by the rabbits’ defense system. Indeed, some rabbits do not show symptoms of infection. However, the bacteria is highly contagious, spreading by direct contact, or through the air in close quarters. Many rabbits are infected at birth through vaginal infection, or shortly after birth while in close contact with an infected mother.

If the pasteurella bacteria become active in the nasal passage, the resulting infection can lead to rhinitis (irritation and inflammation of the nose) initially. From that point the infection often will spread into the sinuses and bones of the face, and further via the inner tubes to the ears, via the nasal tear ducts to the eyes, via the trachea to the lower respiratory tract, and through the blood to the joints, bones, and other organ systems.

Not all infected rabbits become severely ill. The outcome of an infection depends on the potential strength of the bacteria and the host's own immune defenses. More potent strains may produce pleuritic infection (an infection of the membranes surrounding the lungs), pneumonia, and thinning bones. In some cases the bacteria can enter the bloodstream, leading to a condition of bacteremia. An infection of the blood fluid may cause fever, depression, and shock.

Symptoms and Types

Symptoms may be mild, moderate, or severe, but typically consist of sneezing and nasal discharge. Other symptoms include:

• Dizzy, disorientated behavior
• Breathing difficulty (dyspnea)
• Shortness of breath if pneumonia or large abscesses are present in the respiratory tract
• Staining of the front paws (due to discharge collected while self-grooming)
• Excess salivation, facial swelling, and loss of appetite (due to sinusitis or head abscess)
• Excess tears or blockage of the tear ducts
• Head tilt, shaking head, and scratching at the ears if the infection spreads to the ears or the brain/nerves
• Anorexia, depression, pain from skeletal abscesses
• Lameness and reluctance to move (when abscesses are present on the soles and toes of the feet)
• Subcutaneous (beneath the surface of the skin) swelling with subcutaneous mammary abscess

Diagnosis

Your veterinarian will need to begin by differentiating the head and face abscesses from other causes of cold and pneumonia. A nasal swab or flush will be taken for assessing the type of infection that is present, and a complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. To determine the extent of abscesses within the respiratory tract, X-rays of the chest and head region will be taken. Computed tomography (CT) and magnetic resonance imaging (MRI) can also be extremely helpful in detecting the extent of bony changes associated with the disease, as well as any organ involvement.

If available, ultrasonography is the best way to determine the extent of disease and which organ system are affected, the extent of subcutaneous swelling, and the nature of abscess development on the bones and respiratory tract.

Treatment

Your rabbit will be treated on an outpatient basis unless surgery is indicated, or the rabbit is exhibiting signs of severe illness, such as blood infection or pneumonia. Treatment will be focused on treating the symptoms of sneezing and fever. Hydration, nutrition, warmth, and hygiene (keeping the nostrils clean) are of primary importance. Antibiotics and antimicrobials will be prescribed for eliminating the bacterial infection, and pain medications or light sedatives may be prescribed while your rabbit recovers.

If your rabbit is having trouble breathing, humidification of the environment often helps to mobilize nasal discharge and makes the rabbit more comfortable. Saline nebulization (application by liquid spray) may be helpful for humidification of the nostrils as well. If indicated, your doctor may also prescribe oxygen supplementation, and quarantine to a low stress environment. Daily treatment will include gently flushing the eyes and nose ducts to clear the passages of solidified materials before they can crust over the open passages.

If surgical intervention was necessary, or if there were abscesses, you will also need to apply wound care to your rabbit's wound as it heals, bandaging and cleansing as necessary. Multiple surgeries may be involved if there are severe abscesses in the head/brain.

 

Living and Management

The Pasteurella multocida bacterium is highly contagious. You will need to quarantine your rabbit from other rabbits until it has been cleared of the infection and take extra care in keeping the environment and your personal self sanitized to prevent spreading the infection. Restrict your rabbit's activity if there is shortness of breath, or after surgery, setting aside a warm, quiet environment where it can recover.

If the rabbit is not too tired, encourage it to exercise (hopping) for at least 10-15 minutes every 6-8 hours, as activity promotes gastric motility. It is absolutely imperative that the rabbit continue to eat regularly during and following treatment. Encourage oral fluid intake by offering fresh water, wetting leafy vegetables, or flavoring water with vegetable juice, and offer a large selection of fresh, moistened greens such as cilantro, romaine lettuce, parsley, carrot tops, dandelion greens, spinach, collard greens, etc., and good-quality grass hay, along with its usual pelleted diet, as the initial goal is to get the rabbit to eat. If the rabbit cannot eat, you will need to feed it a gruel mixture using a feeding syringe.

High-carbohydrate, high-fat nutritional supplements are contraindicated. In some cases this condition may lead to long standing sinusitis with recurrence, the results depend on the length of infection, the strain of the bacteria, and the strength of the rabbit's immune system.