Encephalitozoon Cuniculi, or E. cuniculi. If you have ever heard those words uttered by your vet in reference to your pet rabbit, no doubt you have left the office with more questions than answers. It is by all accounts, a very perplexing disease and I will attempt to shed some light on it here, as well as put some practical applications on it for us who live with rabbits in our home. What is it? What happens when once the rabbit is infected? What are the symptoms? What tests are there for e. cuniculi? What treatments are there? Examples of e. cuniculi rabbits. What now?