Pasterellosis is an omnipresent disease in rabbits that is revealed in very various forms. It is called this because it is caused by the '' pasteurella multocida '' bacterium and it may sometimes infect the rabbit as early as birth. Depending of divers factors (the bacterial strain, the condition of the animals’s immune system , diet, stress…), it may cause diverse medical problems but, most frequently, it is implicated in respiratory conditions. Infection of the respiratory system, often known as “snuffles”, associated or not with conjunctivitis, is the most frequent manifestation of the disease. Then, followed by otitis, pneumonia or pleuropneumonia, bacteremia (blood infection), and abcesses (subcutaneous, of the internal organs, the bones, joints, and of the genital organs).
We will start by addressing the disease’s effect of the respiratory system, since it is the condition that is most widespread. Whether it be from birth or later in life, when the rabbit encounters the bacterium (which generally is from the respiratory secretions of an infected rabbit), many scenarios are possible. The animal may resist the infection, may fight off the infection and eliminate the bacterium from its organism, can become a carrier of the bacterium without being sick and may develop an acute or chronic disease. The symptoms will evidently differ with each case.
During acute respiratory infection, the main clinical signs presented are rhinitis and sinusitis, sometimes associated with conjunctivitis. Frequent sneezing, cough, transparent nasal discharge that becomes whitish or yellowish, a change in color of the rabbit’s forepaws fur (since the rabbit often grooms his muzzle), respiratory sounds, rapid or difficult breathing, transparent or whitish ocular discharge and hair-loss beneath the eyes are demonstrated. During the general examination, the veterinarian will auscultate the lungs to verify if they are or are not implicated in the condition. If there is a presence of nasal discharge, a sample should be sent to a laboratory in order to confirm the presence of P.multocida since other microbes could cause similar symptoms. While waiting for the results, an antibiotic will be introduced. The results of the culture will also indicate if the chosen antibiotic is effective or not against the secretions’ isolated micro-organism and if its period of medicinal treatment should be prolonged. If necessary, eye drops are prescribed and may go in the eyes as well as the nostrils, depending of the veterinarian’s recommendations. If the rabbit is severely debilitated, he might have to be hospitalized for a couple of days so that appropriate support treatment can be administered (oxygen administration, rehydration, nourishment, warmth…).
To help your rabbit’s recovery, certain measures should be respected in the home. Cleaning your rabbit’s muzzle several times a day if necessary, is the most important. Rabbits, unlike ourselves, cannot breath through their mouths when there is nasal congestion. If the nostrils become completely obstructed with nasal discharge, the rabbit may die. It is also recommended that the cage be cleaned frequently since the odors caused by the urine and stool are irritating to the airways. Similarly, paper litter is suggested instead of wood shavings. A humidifier may be introduced to help excrete nasal discharge and saline use in the nostrils (like we do with our babies) may also have a beneficial role. Of course, it is imperative that you pay particular attention to its appetite and stool consistency. If the rabbit does not eat enough on its own, he must then be force-fed in order to prevent complications associated to anorexia.
Following treatment of the condition, the rabbit can eliminate the bacterium from its organism or become a chronic carrier and later relapse, especially during periods of a weakened immune system (caused by stress, gestation, another disease…). In that case he may develop frequent and even, daily sneezing and perpetual breathing sounds caused by the destruction of the nasal turbinates by the bacterium. Those that are chronic but are feeling well, do not receive antibiotics unless the condition relapses and becomes significantly worse. Some patients receive antibiotics for life…
Otitis occurs when the respiratory infection reaches the middle ear via the eustachian tube. The rabbit may or may not present signs of concomitant sinusitis or, possibly may have in the pass. The infection of the middle ear is very often asymptomatic or is manifested by scratching of the affected ear or by frequent shaking of its head. If the infection spreads to the inner ear, the typical signs can often be most alarming for the owner. They are; torticollis (head bent to one side), subtle to severe loss of balance where the rabbit has difficulty walking around and abnormal eye movement… A radiograph of the skull may be done to confirm the presence of material (pus) in the bulla. Long term antibiotics will be necessary to try and heal the problem. Despite this, it’s possible that the rabbit’s head never returns straight like before and may keep its head slightly bent as a consequence of its infection. The more severe the disease is at the start, smaller are the chances of success.
A bacteremia, a blood infection, develops if the bacterium strain is highly pathogenic. Generally, the rabbit is suddenly very ill, weak, refuses to eat and drink, develops a fever and quickly dies. Often times, it is too late to react… If the condition is less intense, the bacteria circulates in the blood and can cause disorders elsewhere in the organism and be responsible for example of pneumonia, pericardia, etc. These illnesses can develop insidiously and we may come to realize it only weeks later, if not even months later following a bacteremia. Usually, the rabbit is presented for anorexia, weight-loss, depression and sometimes breathing difficulty. Auscultation and radiographs will be necessary to assess the degree of damage. Prognosis is very poor for most of these rabbits.
Subcutaneous abcesses and internal organ abcesses, as well as cellulitis, are also frequently seen in pasteurellosis. The abcesses are generally well circumscribed, solid, non-painful and do not drain like abcesses seen in cats and dogs. It is recommended to remove the subcutaneous abcesses surgically and introduce antibiotic therapy based on the bacterial culture. It’s complicated if the abcess is located on an internal organ, since surgery is not always possible or desirable. If the genital organs are implicated by the infection, whether it be the testes or uterus, which is quite frequent, sterilization is recommended, followed with the administration of antibiotics. If a bone or joint is implicated, the prognosis is poor since the condition is very painful and difficult to cure.
In summary, pasteurellosis is a common disease among rabbits and can manifest itself in so many different ways.
Treatment is possible according to the manifestation of the infection and chances of success depend on the severity of the condition. Unfortunately, there is no vaccine in existence presently available on the market to fight against this disease.