Rabbit hemorrhagic disease (RHD), a rare and reportable disease, has been identified in a pet rabbit from Winnipeg, Manitoba. The affected adult male rabbit was taken to a veterinary clinic in March after being lethargic for a short period of time. It was diagnosed with liver failure and subsequently died. The rabbit’s body was forwarded to the Manitoba Ministry of Agriculture, Food and Rural Initiatives animal health laboratory. Various tests were performed and rabbit hemorrhagic disease was identified.

Rabbit hemorrhagic disease is a viral disease caused by a calicivirus. It is a serious infection that has high death rates and spreads very rapidly between rabbits through direct contact and through contaminated items such as cages and bedding.  It does not affect people. Caliciviruses are non-enveloped viruses – viruses of this kind are very hardy, and can survive in the environment for long periods of time. RHD is reportable in Canada, and has not, to my knowledge, been identified in the country before. It’s endemic in wild rabbits in many countries, and is thought to have made its way to North America in 1988 in a shipment of frozen rabbits from China to a supermarket in Mexico City. It’s been found in the US in sporadic outbreaks since 2000.

Finding RHD in a Canadian rabbit perhaps isn’t too surprising, since it’s been identified in the US periodically over the past decade. However, this is a strange situation. The affected Manitoba rabbit lived in an apartment with two other pet rabbits, and did not have any outdoor access or contact with any other rabbits (or any other wildlife). These other two rabbits were fine. They were quarantined initially but have since been released from quarantine since they stayed healthy and tests for the virus were negative.

So, where did the virus come from? That’s a baffling question, because this virus is a rare and exotic disease that is not known to be elsewhere in Canada. It would have been a lot less surprising if this was in a rabbit with outdoor access or that had had contact with other rabbits (outside of a confined household group). No source has been reported, but I assume authorities have looked at aspects like the owner’s contact with rabbits or wildlife, the owner’s contact with areas where wild rabbits might live, when the other rabbits were obtained and from where, and whether the owner has brought rabbit meat into the house. Although mice and similar rodents aren’t known to be susceptible to the virus, checking for a rodent infestation in the house would be another consideration at in a strange situation like this.

Why were the other rabbits unaffected? That’s surprising as well, considering how easily the virus is normally transmitted.

Another thing this story highlights is the usefulness of diagnostic testing. I’m impressed that the owners and veterinarian submitted the rabbit’s body for testing. Too often, an animal that dies of a strange disease is just buried or cremated. That’s understandable from an emotional aspect, but often it occurs because testing is not even discussed after an animal has died, or because people don’t think about why it might be useful. Cost is an issue, as testing is not typically subsidized for non-food-animals (in this case, even though it was a pet, I presume the rabbit was treated as a food animal, with a lot of testing done for free). While testing won’t help the dead animal, it can provide useful information at times, beyond finding a rare foreign disease. It’s not uncommon for me to get a call from someone saying "my dog recently died of some strange disease, is it safe for me to get a new puppy or do I have to do something first?" or less commonly "I’m sick and the doctors haven’t figured it out. My dog died last month of something strange, do you think they could be linked?‘ With only a vague clinical description, there’s often not much I can say.

Rare diseases are just that – rare. The odds of encountering one are quite low, but they do happen. Arriving at a diagnosis can help identify risks to other pets and people, and it is often money and time well spent.