Coccidiosis is caused by a protozoa – a single-celled organism – of the species Eimeria. While there are 25 different Eimeria types that have been found in rabbits, identification of these individual types is very difficult, and treatment is the same for all.
Coccidiosis is spread through contamination with faeces – the coccidiosis parasites reproduce in the intestines and create infective cysts, which are passed out ready to infect the next animal. Ingested parasites may then remain in the intestine, but in some rabbits can also spread into the liver. Young rabbits are especially susceptible to developing signs of an infection, and in some well-developed cases it can be very difficult to completely cure coccidiosis in a rabbit.