Encephalitozoon Cuniculi

Question
Our 11 month old male rabbit is very sick. He has been seen by our vet twice and will be going back later this evening. He is being treated with anti-biotics and parasite drugs. He had a steroid/cortisone injection yesterday morning. We are not very hopeful. He had paralysis of all four limbs and head tilt, total loss of appetite but maintained bowel and bladder use. We have given two hourly feeds since 9pm on Tuesday throughout the day and night. He started the anti-parasite treatment an hour earlier.

We had another young rabbit who died last August of the same symptoms. The vet thought it was the above parasite. (Both rabbits were not owned at the same time)

He is now eating normally (Not syringe fed)with assistance, has regained some use of his fore legs but hind legs are still paralised. His head tilt has improved.

What are the chances of him regaining his hind leg movement. How long can they be off their feet and recover?

Our first rabbit recovered within 24 hours although he died the following week from what we can only assume was a reoccurance of the same. He was not treated with the parasite drug though as a follow up treatment which we now know may have helped.

We know there is no active treatment but any ideas on treatment or prognosis would be appreciated.

Thanks
Kate

Answer
Dear Kate,

While it's not impossible for such a young rabbit to show such severe symptoms from E. cuniculi, it is pretty uncommon.  Typically, E. cuniculi symptoms come on gradually, and may range in manifestation from hind limb paresis to head tilt.  Renal function may also be impaired, as the parasite infects the kidneys as well as the central nervous system.

I have never heard of a rabbit suffering from paralysis in all four limbs from E. cuniculi--and the symptoms generally do not come on suddenly.  Did this happen all at once?

I don't know why this just came into my head, but I'll share it anyway.  The symptoms you describe could also be consistent with Lyme disease.  You might want to ask your vet about this, since very specific antibiotics must be used to treat this bacterial infection.  In some very severe cases (as when the nervous system is involved), intravenous antibiotics might be necessary.  Lyme disease is sometimes difficult to diagnose, as symptoms can vary greatly between individuals.  But it might be something to ask your vet about, especially if you have *any* ticks in your area. Summer is Lyme disease season.

If this is E. cuniculi, the prognosis could be good if treatment was started quickly and aggressively.  Is he on fenbendazole?  Oxibendazole?  I'm not sure you can get this quickly enough, but another very promising drug is ponazuril (brand name Marquis, made by Bayer), which was developed to treat a similar parasite in horses.

Don't worry about him not being on his feet.  I've had two bunnies who haven't been able to move from their bed for years, and they do just fine.  

I hope your little guy continues to improve, but only time will tell whether his particular infection will respond or not.  The fact that your other bunny died after symptoms subsided really makes me doubt whether this is truly E. cuniculi.  It doesn't sound like the typical presentation of this parasitic infection.

Has the bunny's temperature been taken?  Bloodwork, to check for kidney/liver function?  I also have to wonder whether there is some environmental toxin causing this.  It's just not typical to see full paralysis and head tilt like this with E. cuniculi, especially if onset was sudden.

Please write back if you have more questions.  I hope this is helpful.

Dana