I’m sorry your bun has e cuniculi but it’s good that you now have a diagnosis.

Most buns probably have been exposed to e cuniculi. I think a study in the UK found that 80% of pet buns were carriers. I don’t know about guinea pigs. There are other rabbit pathogens (pasteurella, bordetella) that guinea pigs are very susceptible to so it’s not recommended you house buns and piggies too close together. Wash your hands between rabbits and piggies etc.

Only a few rabbits develop a symptomatic e cuniculi infection, most remain carriers. In most buns the immune defense probably manages to keep the infection under control. Why some buns get an active infection isn’t known. It is probably a lot more common than previously believed though.

If you can find Virkon S, a desinfectant used in horse-stables, it’s bunny safe , odorless and kills a large variety of bacteria, virus and funghi. It’s a powder you dissolve in water and spray after cleaning with, then let dry. It’s sold where horse supplies are sold. Look for the ssmall sachets, it’s also sold in big buckets but you’re not disinfecting a stable so you don’t need that.

I think laundrying at 60 degrees C (140 F) or above will kill the spores. A bun can get reinfected. It’s not a lot we can do about that though, we can only try to keep stuff as clean as possible. A bun will often remain a carrier of the parasite because it’s very difficult to eradicate.

Some vets suggest that exposed but unsymptomatic buns are treated with Panacur for nine days. It’s not clear if that has any preventative effect or not.