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
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.