Yersiniosis in Rabbits: Bacterial Infection, Diarrhea, and Fever

Yersiniosis is an infection caused by bacteria in the Yersinia group, most often Yersinia pseudotuberculosis. In rabbits, it is considered uncommon but important because it can affect the intestinal tract, nearby lymph tissue, and in severe cases spread more widely through the body. Merck lists yersiniosis as a zoonotic disease associated with Y. pseudotuberculosis, meaning people can also be exposed in some situations through contaminated material or infected animals.

In a rabbit, this infection may show up as diarrhea, poor appetite, weight loss, fever, and low energy. Some rabbits develop more vague signs at first, which can make the problem easy to miss. Because rabbits are sensitive to dehydration and gastrointestinal imbalance, even a short period of diarrhea or not eating can become serious.

Yersiniosis is not the most common reason a rabbit has diarrhea. Diet problems, coccidia, inappropriate antibiotic exposure, and other infections are often higher on the list. That is why your vet will usually approach this as part of a broader workup for gastrointestinal disease rather than assuming one cause right away.

Yersiniosis is caused by infection with Yersinia bacteria, especially Yersinia pseudotuberculosis. Merck notes that this organism is found in temperate regions and is typically spread by ingestion of contaminated material. In practical terms, a rabbit may be exposed through contaminated food, water, feces, bedding, or a dirty environment. Wild birds, rodents, and other animals may also contribute to environmental contamination.

Rabbits are more likely to become sick when normal gut defenses are disrupted. Stress, overcrowding, poor sanitation, sudden diet changes, low-fiber feeding, and concurrent illness can all make intestinal disease more likely. VCA also notes that rabbit diarrhea has many possible triggers, including bacterial infection, parasites, diet imbalance, toxins, and inappropriate oral medications.

Not every exposed rabbit becomes seriously ill. Some may carry bacteria with few outward signs, while others develop intestinal inflammation, enlarged lymph nodes, or systemic infection. That variation is one reason your vet may recommend a broader diagnostic plan instead of treating based on symptoms alone.

Diagnosis starts with a careful history and physical exam. Your vet will want to know when the diarrhea started, whether your rabbit is still eating hay, what the droppings look like, whether there has been weight loss or fever, and if there were any recent diet, housing, or medication changes. Because diarrhea in rabbits has many causes, the first step is usually to stabilize the rabbit and narrow the list of possibilities.

Testing often includes fecal evaluation to look for parasites such as coccidia, along with bloodwork to assess hydration, inflammation, and organ function. If bacterial infection is strongly suspected, your vet may recommend fecal culture, culture of affected tissue, or other laboratory testing to identify the organism and help guide antibiotic choices. Imaging such as radiographs or ultrasound may also be used to check for gut slowdown, gas buildup, enlarged organs, or other complications.

In some rabbits, yersiniosis is only confirmed after more advanced testing or, in severe cases, tissue sampling. That can sound frustrating, but it is important because treatment decisions in rabbits need to be careful. Some antibiotics are safer than others in this species, and the wrong medication can worsen gastrointestinal disease.

Prevention starts with good rabbit husbandry. Keep housing clean and dry, remove soiled bedding promptly, wash food and water containers regularly, and protect hay and pellets from contamination by rodents, wild birds, and insects. Fresh water and a high-fiber diet centered on hay help support normal gut function, which is one of a rabbit's best defenses against intestinal disease.

Try to avoid sudden diet changes, overcrowding, and unnecessary stress. VCA notes that rabbit diarrhea can be triggered by low-fiber feeding, rapid diet shifts, inappropriate medications, and infections, so prevention is often about reducing several risks at once rather than focusing on one germ. Quarantining new rabbits before introducing them to the household can also lower the chance of bringing in infectious disease.

Because yersiniosis is considered zoonotic, basic hygiene matters for people too. Wash your hands after handling a sick rabbit, cleaning litter areas, or touching feces. If anyone in the home is immunocompromised, pregnant, very young, or elderly, ask your vet and physician about extra precautions while your rabbit is being evaluated.