Clostridiosis (also known as enterotoxemia) in rabbits is life-threatening and often caused by an overgrowth in the intestines of the anerobic bacterium Clostridium, of which several strains may be responsible.

©Jessica Death

Young rabbits around the age of weaning (5-8 weeks) and those kept in colonies, especially in crowded and unsanitary conditions, are more at risk of acute and serious cases of enterotoxemia. However, occasionally well-kept pet rabbits can be affected, as can rabbits that have been treated with certain types of antibiotics.

Enterotoxemia causes a sudden onset of liquid, watery, foul-smelling diarrhea, which may be also covered in mucous. The diarrhea can be intermittent to begin with but will become more severe as the disease progresses. Other signs that develop include abdominal pain and painful tooth grinding, lack of or loss of appetite, listlessness, and depression, rapidly followed by collapse and death. Many affected rabbits succumb to the disease within 1-3 days.

Transmission of the bacteria from one rabbit to another occurs through eating food contaminated with the bacteria from infected rabbit’s feces and is one reason why rabbits kept in crowded conditions are more at risk. Young rabbits are more at risk as their immune system and microflora within the digestive system are not fully established. Higher stress levels at this time, increases their risk further. In adult rabbits, other factors that can cause infection include high levels of stress, some antibiotics, and diets that are high in carbohydrates and sugar, and low in fiber. Feeding large amounts of fruit, grains, cereal based treats and other inappropriate foods increases the risk, as do sudden dietary changes which disrupt the healthy microflora in the intestines (cecum).

After a rabbit becomes infected with a pathogenic (disease-causing) strain of either Clostridium spiroforme, Clostridium perfringens or Clostridium difficile the bacteria start to colonize the small intestine and cecum, multiplying and producing enterotoxins, which rapidly disrupt the normal intestinal microflora and overwhelm the rabbit’s digestive system, and can also enter the bloodstream, causing dehydration, toxemia, electrolyte loss and rapid death.

In severe cases treatment is often not successful and most rabbits are found dead or dying, since the progression of clinical signs and disease is rapid. When treatment is attempted, it must be prompt and aggressive. Intravenous fluid therapy and supportive care are required. Antibiotics are likely to be prescribed and your rabbit will require hospitalization for intensive nursing care. The prognosis is extremely guarded, and the majority of rabbits do not recover. In adult rabbits whose signs may not be as severe, treatment is more likely to be successful, but in all cases the quicker the veterinary treatment is started the more likely it is to succeed.

With all rabbits, keep stress levels to a minimum. Avoid overcrowding, proximity to predators, extremes of temperature and anything else that might cause stress, such as loud noises and disturbance, or bullying from other rabbits. Keep your rabbits in compatible pairs or groups in a clean environment which is large enough to meet their needs – a minimum of 3m x 2m for 2 average sized rabbits, with quiet hiding and sleeping areas they feel secure. Do not allow your rabbits to mix with other rabbits, and especially do not allow them to graze on grass that other rabbits have had access to. Feed a diet that is high in fiber with the correct about of carbohydrate – this should be at least 85% hay and grass, 10% rabbit friendly herbs and greens, such as parsley, coriander, mint, basil, greens, celery etc, avoiding fruits and carrots, and 5% good quality pellets. Do not be tempted to feed human food to your rabbit and avoid ‘treats’ which are high in sugar, grains and seeds. Any treats should be hay based to ensure they are healthy. And finally, make sure you use a rabbit-savvy veterinarian who is aware what antibiotics to avoid in rabbits.