Pasteurellosis is a common bacterial disease in rabbits, causing a range of health issues. Widespread in rabbit populations, it can lead to various clinical signs and serious complications.
Understanding the Disease
The bacterium Pasteurella multocida is the primary cause of pasteurellosis in rabbits. This gram-negative bacterium is frequently carried by rabbits without showing signs of illness; 30% to 90% of healthy rabbits may be asymptomatic carriers. Rabbits often acquire P. multocida soon after birth, with colonization increasing up to about five months. Most adult rabbits are believed to harbor this bacterium.
Transmission of Pasteurella multocida occurs primarily through direct contact with infected rabbits, especially via respiratory secretions and aerosol droplets from sneezing. Contaminated environments, including bedding, food, and water bowls, can also facilitate indirect spread. Once the bacteria enter the body, typically through the nose or open wounds, they can colonize nasal passages and spread to other organs.
Certain factors can predispose rabbits to developing an active infection. Stress is a trigger, as it can suppress the immune system, allowing the bacteria to proliferate and cause disease. Poor environmental conditions, such as inadequate ventilation, high humidity, and ammonia buildup from soiled bedding, also increase the risk. Overcrowding further contributes to stress and facilitates rapid transmission within a group.
Recognizing Symptoms
The clinical signs of pasteurellosis in rabbits are diverse, depending on the affected body system. A common manifestation is an upper respiratory tract infection, known as “snuffles.” This condition often begins with sneezing and watery nasal discharge, progressing to a thick, mucopurulent discharge. Affected rabbits may make snuffling or snoring sounds due to mucus obstruction.
Rabbits often groom their faces with their front paws, leading to matted fur on their forepaws from nasal discharge. The infection can also spread to the eyes, causing conjunctivitis with redness, soreness, and discharge. Tear duct infections (dacryocystitis) may also occur, leading to excessive tearing and fur staining below the eyes.
Ear infections, specifically otitis media and interna, are another common presentation. If inflammation extends to the vestibular apparatus, rabbits may develop neurological signs like torticollis, or “wry neck.” This can lead to head tilt, loss of balance, circling, and involuntary eye movements (nystagmus).
Skin abscesses are frequently observed as firm swellings containing thick pus. These can occur anywhere, including under the skin, in the jaw, or at tooth roots. Less common but severe forms include infections of internal organs, such as pneumonia or reproductive tract infections like metritis or orchitis, which can cause vaginal discharge or infertility. In some cases, septicemia, a systemic bacterial infection, can occur, leading to acute death without obvious signs.
Diagnosis and Treatment
Diagnosing pasteurellosis involves observing clinical signs and conducting laboratory tests. A veterinarian will perform a physical examination, noting respiratory sounds, discharges, or swellings. While clinical signs suggest pasteurellosis, definitive diagnosis often relies on bacterial cultures from affected areas, such as nasal or eye discharge, or abscesses. These cultures identify Pasteurella multocida and determine antibiotic susceptibility.
Imaging techniques, such as X-rays or CT scans, may be used in severe cases to assess internal damage, particularly for pneumonia, ear infections, or deep abscesses. Blood tests, including a complete blood count (CBC) and chemistry profile, provide information on overall health and systemic infection. A positive culture alone does not always indicate active disease, as many healthy rabbits are asymptomatic carriers. Serological tests, like ELISA, can detect antibodies to Pasteurella and help identify carriers.
The primary treatment for active pasteurellosis involves antibiotic therapy. Antibiotic selection is guided by bacterial culture and sensitivity testing to ensure effectiveness against the specific Pasteurella multocida strain. Commonly used antibiotics include enrofloxacin, trimethoprim-sulfa, chloramphenicol, penicillin G, and azithromycin.
Antibiotic treatment is often prolonged, typically lasting 14 to 30 days, or even several months, to control the infection. Complete eradication can be challenging, and recurrence is possible, especially during stress or if treatment stops prematurely. Supportive care is also important, including cleaning discharge, managing abscesses through surgical drainage or removal, and providing fluids or assisted feeding if the rabbit is anorexic or dehydrated. Veterinary consultation is recommended for proper diagnosis and a tailored treatment plan.
Prevention Strategies
Preventing pasteurellosis in rabbits involves maintaining excellent husbandry practices and minimizing environmental stressors. Good ventilation in housing areas reduces airborne bacteria and ammonia, which can exacerbate respiratory issues. Regular cleaning and disinfection of cages, bedding, food dishes, and water bottles also reduce bacterial load.
Stress reduction plays a role in preventing active infections, as stress can suppress a rabbit’s immune system. This includes avoiding overcrowding, ensuring a stable environment, providing appropriate nutrition, and managing social dynamics. A balanced diet and clean water contribute to a robust immune system, helping rabbits fight off infections.
Implementing quarantine for new rabbits before introducing them to an existing group is a preventive measure. New rabbits should be isolated for about one month to observe for illness and prevent pathogen spread. Even healthy rabbits can be asymptomatic carriers, making quarantine a valuable step.
While some commercial vaccines against Pasteurella multocida exist, their effectiveness can vary. Current vaccines may not protect against all strains, nor fully prevent nasal colonization or eliminate the carrier state. They may help reduce the severity of clinical signs and mortality rates. Ultimately, a healthy, low-stress environment combined with diligent hygiene practices forms the foundation for minimizing pasteurellosis risk.