sudden rabbit deaths

Question
QUESTION: I have been keeping pet house rabbits for the past 4 years and during that period three of them have died suddenly in separate incidents but with exactly the same symptoms. The first died 3 years ago, the second the year after and the third, Clementine , died suddenly last night. She was exhibiting no clinical symptoms when I fed her at 7pm and she ate her food.
However I started to worry about her after an hour or so when I noticed she still hadn't come out of her enclosure for a run. She had produced some slightly soft droppings that were stuck together but with no mucus, and she was lethargic. I gave her some metoclopramide and meloxicam hoping that she would pick up and I also syringe fed her later on. At 2am she suddenly developed laboured breathing and ataxia, and was falling about so I rushed her off to the emergency vets but she was dead on arrival.
None of the vets I have seen have been able to identify the cause of such sudden death in my rabbits, even the exotic specialist I took one of them to previously. The original rabbit, Fern became ill after I obtained two pedigree kittens that arrived with a virus that made all my pets ill at the time and I am worried that my cats are still carrying a virus that might be the cause of the rabbits' deaths.
Obviously this is a very upsetting situation for me and I would be extremely grateful if you could offer any advice or information on what you feel may be causing this problem as nobody else seems to be able to help.

Thank you.

ANSWER: Dear Julie,

I am very sorry for these tragic, sudden deaths.

Were necropsies performed on any of the rabbits?  Without information from gross necropsy and histopathology on all major organs, there is no way to positively ascertain the cause of death.

Since this happened to three different rabbits, I have to wonder if there was some toxin involved.  Were they all eating the same food?  Was there pesticide sprayed in the house?  Other sources of poison?

Still, the only way to know for sure is via necropsy.  I know it is too late for that now.  And I hope you don't have cause for a necropsy in the near future.

Dana

---------- FOLLOW-UP ----------

QUESTION: Hello Dana

Thank you for your reply.

We did consider a toxin such as contaminated food but thought it unlikely as none of my other rabbits were affected at the time of the deaths, including each rabbits bonded partner. Also it would be exceptionally bad luck to buy contaminated food on 3 separate occasions. Unfortunately there are no local facilities that perform rabbit post mortems so I was unable to establish any further facts.

Each of the deaths has occurred in the summer so I was wondering whether you are aware of any bacterial/viral disease that may be carried by flying insects, etc that may be more prevalent in the warmer weather? All my rabbits are vaccinated for myxi and VHD so neither of those should be a problem. Obviously I am very worried that this is something virulent that could affect my remaining and any future rabbits I acquire.

Also, it may be worth noting that all of the rabbits who died were young, no more than a year old, so I am wondering whether my older rabbits have developed some resistance to whatever is causing the issue?   

Thanks again for your help.

Julie

Answer
Dear Julie,

Your idea about the younger rabbits not having immunity to something the older ones do is an interesting one, and not unreasonable.  But there is no way to know for sure without necropsy.

Unfortunately, that's where this ends up.  Without necropsy, everything else is a guess.

I am very sorry.

Sincerely,

Dana