Differential diagnosis

There are several differential diagnoses for sudden death in rabbits but the histopathological finding of hepatocellular necrosis is highly suggestive of RHD.  Other causes of  hepatic necrosis  includes:

Poisoning

Poisoning is a concern for many owners of rabbits that die suddenly, especially if there are multiple deaths in the same household. There are no plants that cause acute hepatic necrosis in rabbits. Aflatoxins, copper toxicity and some compounds e.g. norepinephrine can cause liver necrosis, but ingestion of these compounds is unlikely in rabbits kept as pets and death is not sudden. Histopathologically, the type of hepatic necrosis is different from RHD. In the case of aflatoxicosis, there is bile duct hyperplasia and copper toxicity is characterised by the presence of small black or greenish granules in the necrotic hepatocytes.

Heatstroke

The post-mortem findings in cases of heatstroke include pulmonary haemorrhage, necrosis of the liver and signs of disseminated intravascular coagulopathy, such as fibrin thrombi in small blood vessels. The histopathological pattern of hepatocellular necrosis and the circumstances surrounding the deaths are likely to suggest heatstroke as the diagnosis.

Sepsis

Sepsis is a cause of sudden death in rabbits, but it is unlikely that multiple rabbits will be affected. Histopathologically, hepatocellular necrosis and disseminated coagulopathy may be present but the pattern of liver necrosis is different from RHD (Harcourt-Brown et al. 2020). Bacteria may be evident in the tissues.