Ten days ago, I purchased a 9 week old NZ buck. Within a day, he was off his feed completely. And a day later, he was not drinking so I began force feeding water.l with a little ACV, electrolytes and probiotics. He has been urinating. Due to the heat, I decided to bring him inside during the days. About 5 days ago, he has feces/urine dried on his genitalia/anus which we cleaned as best as possible. Today, I found clear jelly like material coming from his anus. It did not smell foul.
I have already decided I was not going to breed him, but keep him as a pet for my kids since he has such a sweet personality. But I have two questions, 1) is this fatal? And 2) could this be transmissible to my children?
Rabbits' guts will produce mucous when they're irritated; I would not be overly concerned about transmissibility, but I would probably keep him away from younger kids that are too young to be conscientious about handwashing. It's probably simply gut upset from the move, but it's hard to say if there is some other pathogen involved that could be carried in the mucous.
Mucoid enteritis isn't necessarily fatal, but it can lead to fatality due to gut stasis (a stalling of the normal gut movements so critical in herbivores). The bunny has a horrible stomach ache and as a result, won't eat anything. Your goal is to keep
something going in and something coming out, to avoid stasis while his gut fauna gets re-balanced.
To deal with mucoid enteritis I usually take the rabbit off pellets (you can leave pellets in his feeder, but I wouldn't force feed him pellets, as those can be part of the problem) and give lots of hay, changing it out often to make sure it stays clean.
However, if he's been like this for more than a week, he's probably past the point where he'll eat the hay or anything else, so I'd agree with
@TKT 's suggestion to try to get some Critical Care for Herbivores into him. Mix it with warm water, making it thin enough to push it into his mouth with a small syringe; start with a
very thin consistency so it will basically run down his throat. Be patient and just get a little bit into him multiple times a day. Remember, he has a bad stomach ache, so you don't have to force a full meal into him; you just want to keep things moving. Just keep squirting a little in until he stops letting it run down his throat. I would probably not add ACV since rabbits don't usually like the taste of that, and you don't want to do anything to discourage him from eating and drinking. I would also leave out the applesauce, since sugar tends to encourage the growth of problematic microorganisms in the gut. I do suggest squirting a bit of Benebac (small animal probiotic) into his mouth once a day; most rabbits like the taste of that very much.
Another thing to try is to leave something very tasty in where he can nibble it when he starts feeling better. Greens like young dandelion leaves, chickweed, and/or wild plantain can sometimes tempt a bunny. Parsley, while it usually isn't their first choice, seems to stimulate appetite when they are willing to taste it.
A key thing we did with Mini Rex bunnies seemed to be holding and petting them (i.e., love!). One little guy that was on death's door with the worst case I ever saw, only ate or drank when he was being held, and he actually survived when we brought him in and did that every few hours.
Sometimes it's also been necessary to give them Neomycin oral if they continue to go downhill due to some particularly nasty microorganism having taken over their gut. Unfortunately, now that's prescription only, but you can still find it in pet stores as Oasis Dry Tail for hamsters. I don't like to use antibiotics unless it's absolutely necessary, but it's an old and safe preparation and I do believe it was what turned a couple of our bunnies around. If you give that, be doubly sure to also give him Benebac.
If he's been dealing with this for 8-10 days, be aware that you might have a hard time bringing him back. But it's worth a try; I've seen some pretty bad cases almost come back from the grave. I certainly would stick with the plan of
not using him for breeding, but the good news is that he'll probably end up the tamest, sweetest bunny ever, after all the love and attention.
EDIT: I forgot something important. If you can find willow trees or bushes, give your bunny some branches with the bark intact. The bark contains a natural analgesic called salicin (it used to be used to make aspirin), as well as several anti-inflammatory compounds. Rabbits will often chew on willow branches even if they're not eating.