E Cuniculi treatment with Panacur

Question
Mid July, my daughter's rabbit, Peanut, started having a head tilt and loss of balance.  We took him to the vet, and they treated him with Pancur and an antibiotic.  Although we didn't have a test run to confirm E Cuniculi, One of the vets in the office had a rabbit with the same problems, and felt strongly that he was a victim of EC.  Peanut got better within a few days, and we finished the prescriptions.  At the time I was under the impression that this medication would kill the parasite.  In September he got the same symptoms only worse, where he would fall completely over and spasm until he could get back upright.  We treated again with the same prescriptions. (Not concerned that the first prescription probably didn't kill the parasite).  Peanut got better again, but last week began with the head tilt again, and this time we called the vet and began a third round of the same prescription.  He has seemingly recovered from the symptoms yet again.  I have now done a little research, but am finding that EC probably isn't something that can be eradicated.  I don't know if we should expect that Peanut will end up with an paralysis or not, but he seems so much better when he is treated with the Pancur than when he is not.  So my question is really related to longterm use of Panacur.  Can it be given to him for the rest of his life? or Should it be?  Do you know of other treatments for E Cuniculi?

Answer
Dear Cindy,

To my knowledge, a 28-day course of Panacur should eradicate the parasites, and unless he's being re-exposed by contacting urine from an infected rabbit, it's not all that likely that these symptoms are still due to E. cuniculi (though it's not impossible).  Note that there are MANY different possible causes for head tilt, and I'd start by reading this excellent article by Dr. Susan Brown, a renowned rabbit vet:

www.rabbit.org/health/tilt.html

It's possible that your bunny has a chronic ear infection that keeps cropping up, and requires antibiotic treatment.  

There is another drug that is under experimental use for E. cuniculi treatment:  Ponazuril (brand name Marquis).  It was developed for use in horses to treat a similar microsporidian parasite, and although it's expensive, it may be something to discuss with your vet.

I hope this gives you some options for your little guy, and gets him on the road to full recovery.

Dana