Hi Grumpybabies,
The symptoms you describe are consistant with ecunculi. This is a protozoa, the simplest form of life onearth, that has invaded the brain. It is spread thru theurine of an infected rabbitor at birth from an infectedmother. Nearly all domestic rabbits have hadexposure. In the best situation, the rabbit's immune systemwill keep this organism under control. However, once itbreaks out, bad things happen. Usually the first indicationof a problem is a "lazy leg"...a leg that might drag every once in awhile. Then the rabbit will become very unstable in the hindquarter and will eventually go down on his side. Over thenext few days, there may be marked improvement with the bun upright andin many cases running around. This is the rabbit's immunesystem mounting a counter attack. However, EC is a wastingdisease that will cause a general decline in health over a period ofmonths and sometimes years. The spores will damage thekidneys and renal failure is very likely over a period oftime. Due to a compromised immune system, a bun with EC isvery likely to have multiple bacterial infections during the course ofthis disease. As the disease progresses, the rabbit will losenearly all of the hind quarter voluntary function and usually one ofthe legs will become very rigid. Urinary incontinence fromthe damaged kidneys will usually result in painful scalding.
The only way to confirm EC by diagnostics is post mortem.There is an "EC Titer" which is an advanced blood panel thatspecifically looks for antibodies to EC. The results aresubject to interpretation. The test is not fool proof, iscostly and only a couple of labs can perform this test.
Treatment is difficult. There are many that claim thativermectin will cure this issue. There are those that claimantibiotics will cure it. Simply not true. It's nota bacteria so an antibiotic will have no effect. Problem withmany of the treatments is getting the drug past the blood/brainbarrier. The latest treatment, with mixed results, is withthe "bendazoles"...with the latest being Panacur. It'sbasically a horse wormer. Standard procedure for treating ECis a daily round for at least 30 days..and we treat for 60.Honestly, and we have treated several here in rescue, I really have notseen any treatment be anything other than marginally effective. Andwith the current treatment, the best we can do is buy time.There is some work on using a drug called "Marquis" that is used totreat Equine Protozoal Myeloencephalitis (EPM) in horses. Nofirm results on that due to the small number of unofficial researchbeing done. Most of this treatment is being done by some ofthe more advanced exotic vets working in the field.
Rabbits with EC can live quite a while after issues arise. Infact, we have known of some buns that go into a type ofremission. Generally, the disease takes away a little at atime. Good husbandry from their humans can make thissituation much better for the rabbit. They will lose muscletone as they have difficulty moving around. A good massageand gently working those rear legs can help. Be on constantguard for bacterial infections that seem mainly to involve eyes, upperrespiratory and urinary tract. Hydration, by sub-q or IV ifnecessary, will be required to support the damaged kidneys as thedisease progresses. The rabbit will lose weight and have ageneral overall decline in all aspects of life.
I can't stress the importance of TLC when dealing with thisissue. Buns will give up quite easily so if EC is theproblem, extra care will help. There are also companies thatcan build very stable carts to assist with mobility. I knowthis post sounds all gloom and doom. I don't mean it to bethat way. Yoda is a very special rabbit that lived with usfor years. As he aged, he developed EC. He lived avery good life right up until the last week or so of hislife. We just could not overcome the kidney damage.But he lived over two years after the first indication of aproblem. We did some aggressive husbandry...but it was worthall the effort. We feel the extra TLC did as much,if not more, than all thedrugs we used in treatingthis.If you have any questions, feel free to contact me byPM. Best wishes.
Randy