ponazuril treatment for E.C.

Question
Hi Dr. Krempels,

One of the bunnies in our sanctuary is suffering from a case of E.C.  we took her to Specialized Care (veterinarian for exotic pets only) the blood test showed a 'moderate' amount of E.C.  I have no idea what a moderate amount is but she said it is not likely an acute attack.  We have started the bunny on the ponazuril.  How long would it normally take to see results?  I have seen nearly immediate results when treating for coccidiosis and I was wondering if the ponazuril actually kills the parasite?  Do the bunnies return to normal after treatment?  Although she is eating, drinking and pooping normally it is killing me to watch her try to get around.  She crawls rather than hops but every once in a while she loses her balance and flops over like a fish and she has a huge fit that looks like a seizure (although I know it is not she is just trying to get her balance).  Before her E.C. attack she had a chronic sneeze for over a year.  She has a deep nasal culture that showed nothing.  She was treated with Baytril and Zithromax and still sneezed.  She never had nasal discharge but we did not put her up for adoption because we did not want a new owner to have to worry about her health issues.  I read an article somewhere on a local HRS site that sometimes they use metacam with the ponazuril to reduce swelling.  

I guess my questions are:

1.  How long for ponazuril to show signs of improvement?
2.  How long will she need to take the ponazuril?
3.  What is the shelf life for compounded ponazuril (it is refrigerated)
4.  Is it possible for the sneezing to be related to the E.C. somehow?
5.  Is there any reason to believe that metacam may help?

I want to learn as much as I can about the bunnies so that I can get them proper care and treatment.  Had I not noticed the very subtle shaking of her head I may not have caught this illness as quickly as I did. Thank you so much for dedicating so much time to helping all bunnies.

Sincerely,

Angela

Answer
Dear Angela

1.  How long for ponazuril to show signs of improvement?

It's pretty much impossible to say.  If this is really E. cuniculi, and not, say, an inner ear infection, then it depends on whether the parasite has caused neurological damage (not generally reversible), or if the abnormal behavior is due to inflammation (will be helped by metacam, and possibly the ponazuril).

No one really knows if ponazuril or Panacur (fenbendazole) actually kills the parasites.  Ponazuril supposedly kills a very similar parasite in horses, but no research has been done on rabbits, to my knowledge.

2.  How long will she need to take the ponazuril?

This, too, is unknown.  If she improves and you take her off and then she gets worse, it could be a lifelong (if intermittent) thing.

3.  What is the shelf life for compounded ponazuril (it is refrigerated)

The Bayer site indicates that it is quite stable.  But there should be an expiration date on the tube.  (Most medications are good for long beyond their "official" expiration, though, with a few exceptions (e.g., metacam).

4.  Is it possible for the sneezing to be related to the E.C. somehow?

Not likely, but the "medium" titer for E. cuniculi could be a Red Herring.  Many rabbits have antibodies for the parasite, but do not show signs of illness from it.  Others may have the parasite and not have a significant titer, but no other pathology can explain their clinical signs (e.g., head tilt, hind limb paresis).

The sneezing *could* be indicative of an intracranial infection, though.  And that could be causing E. cuniculi-like signs.  It's very difficult to know for sure, especially with an inner ear infection that may not be visible even with an otoscope exam.

5.  Is there any reason to believe that metacam may help?

Yes, if the problems are partly due to inflammation.  The metacam will reduce this, and could help.

Unfortunately, we're still on the cutting edge of treatments for E. cuniculi, and most of what we know is anecdotal.  I hope your little gal gets better soon.

Dana