by Astrid M. Kruse, DVM
The word "Pasteurella" strikes fear into the hearts of many bunny lovers.
It conjures up images of nasty abscesses, of sticky noses, of sick sad
bunnies. An understanding of what Pasteurella is and what it does is
important in keeping your bunny healthy. Pasteurella multocida is a type of
bacterium, a single-celled organism that can be inhibited or killed by
specific antibiotics. Pasteurella can be acquired from anywhere, especially
other bunnies, and often humans who may carry it on their skin or clothing.
The bacteria enter the body via the nose or open wounds and start growing.
Over half of all rabbits carry Pasteurella bacteria in their bodies, but
most are not sick. A healthy immune system either eliminates the bugs from
the system, or keeps their numbers and location tightly controlled where
they are harmless. However, some rabbits are not able to destroy the
Pasteurella that has colonized their bodies and develop pasteurellosis,
clinical disease. Pasteurella infection is diagnosed from positive nasal
cultures, obtained by sticking a sterile swab up the nose, smearing the
bunny boogers on an agar plate, and seeing what bacterial colonies grow.
However, the mere presence of Pasteurella does not establish that
Pasteurella is actually causing the current disease since most bunnies test
Commonly, rabbits with pasteurellosis show upper respiratory disease, also known as "snuffles". Rabbits clean and wipe their runny noses, unlike children, unless they are very ill. The slight crusting around the nostrils may go unnoticed, but the fur on the insides of the forepaws should be checked because this is where the discharge accumulates. With a worsening infection, the clear discharge becomes pus-filled. The infection may spread into the lungs and around the heart, leaving abscesses. Rabbits can also develop conjunctivitis, an eye infection, and blocked tear ducts. The Pasteurella bacteria may travel into the ear via the eustachian tube (what you pop open in an airplane). A middle ear infection is irritating; an inner ear infection is frightening because the balance (vestibular) organ is affected. Rabbits with deep ear infections will tilt their head or roll because their brain thinks the world is spinning due to signals from the infected vestibular organ. Anyone who has ever nursed a bunny through vertigo deserves a medal, and the bunny is entitled to extra treats. Abscesses caused by Pasteurella are all too frequent, and can appear anywhere on the body, although tooth root abscesses are common. The pus in an abscess is composed of dying bacteria and white blood cells (neutrophils) that are fighting the infection. Pasteurella abscesses often contain a dense, cheese-like pus that will not drain but requires surgery to scrape it out. Even after surgery, the infection frequently recurs. Many vets are now implanting beads with antibiotics into the infected site, which release antibiotics in high concentrations into the local tissues and can be very effective in preventing recurrence. New strategies for dealing with these abscesses are being developed- make sure your vet knows the most current therapy.
The risk of Pasteurella infection and illness can be reduced, although not eliminated. After contact with other rabbits and cats (and people?), thoroughly wash hands with soap and warm water and towel dry; you can also add an alcohol-based sanitizing gel. Change your clothes and shoes if you've been visiting the rabbits at the shelter before you enter your own bunnies' area. Clean the litter before an ammonia smell builds up at ground level, which can damage the bunny's respiratory tract and allow bacterial colonization. Keep your rabbit's immune system in top shape by keeping her cool, feeding her fresh vegetables, and having an emotionally healthy rabbit who gets lots of loving attention. Studies show that human blood pressure drops when petting an animal- cuddling is therapeutic for everyone! Above all, if you suspect that your bunny is ill, take him to the vet. Antibiotics can do a lot to help the body fight off bacteria and therapy can cure your bunny. However, some rabbits do develop a chronic low-grade infection that can be kept under control with life-long antibiotics.