A common upper respiratory tract infection is caused by a bacterium called Pasteurella multocida which is carried asymptomatically by healthy carrier rabbits. Clinical signs are often precipitated by stress, extremes of temperature, overcrowding, concurrent disease, or poor ventilation. It can infect the tear ducts, and may result in conjunctivitis, or middle ear disease. It may also cause secondary infections in the skin and internal organs.
Another common condition associated with the bacterium is upper respiratory tract infection known as Snuffles. When the rabbit is under stress the immune system may be compromised, leading to expression of clinical signs. Veterinary treatment may include antibiotics but these are not always successful and ideally antibiotic sensitivity should be carried out prior to commencing treatment.
Prevention is not always possible, but keeping the rabbits generally healthy and stress free can help prevent the onset of clinical signs. The bacterium is easily transmitted by close contact between rabbits, so any new rabbits should be isolated for about one month before introducing them to existing rabbits.