Todayโs path rounds are on ๐ก๐๐ฉ๐๐ญ๐ข๐ ๐๐จ๐๐๐ข๐๐ข๐จ๐ฌ๐ข๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ฉ๐๐ญ๐ข๐ ๐๐จ๐๐๐ข๐๐ข๐จ๐ฌ๐ข๐ฌ is an infection of the liver with ๐๐จ๐๐๐ข๐๐ข๐, which are small single celled protozoans. Typically, these protozoa cause intestinal disease, making hepatic coccidiosis a somewhat unique presentation for this parasiteโs life cycle.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
This disease is typically seen in rabbits!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Hepatic coccidiosis in rabbits is caused by the coccidian ๐๐ข๐ฆ๐๐ซ๐ข๐ ๐ฌ๐ญ๐ข๐๐๐๐. This protozoa enters the rabbit in contaminated feed or water. From there, they invade into the small intestine and migrate to the liver. Once in the liver, they make themselves a house in the cells lining the bile ducts, and begin to replicate. These protozoa will then release their infective egg form into the bile, to eventually be excreted in the animalโs feces and continue the life cycle.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
The bile duct cells donโt love having protozoa in them, so they will often become ๐ก๐ฒ๐ฉ๐๐ซ๐ฉ๐ฅ๐๐ฌ๐ญ๐ข๐ (increase in number) and ๐ก๐ฒ๐ฉ๐๐ซ๐ญ๐ซ๐จ๐ฉ๐ก๐ข๐ (increase in size) as a response to their new friends. The protozoa will also stimulate a lot of inflammatory cells to come into and around the bile ducts, which can give the bile ducts a white appearance that can be seen at necropsy. Cool!
Ultimately, having the bile ducts going crazy and having an inflammation party in the liver can lead to liver disease, which makes the rabbits feel quite sick. These rabbits may stop eating and will not grow to their full size. Sometimes they can even die from infection if it is severe enough.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
The best way to diagnosis this disease is on a necropsy, where you see white nodules on the liver representing the proliferating and inflamed bile ducts. In a living rabbit however, the best diagnosis would be a fecal float to detect the protozoal eggs, combined with an ultrasound to visualize the nodules on the liver.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Unfortunately treatment is very difficult for these little guys. The rabbits must have a long course of ๐๐จ๐๐๐ข๐๐ข๐จ๐ฌ๐ญ๐๐ญ๐ฌ (medications that prevent coccidial replication) to reduce the shedding of the infective eggs, combined with environmental changes to reduce transmission of any eggs that are shed. Thankfully, if a rabbit does successfully recover from infection with complete clearing of the protozoa, they are immune and will not get re-infected.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-5) Some wonderfully spotty livers showing the white nodules of bile duct proliferation!
6) What a pathologist would see under a microscope! I have tried to identify as many different life stages of the protozoa as I can.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Mayer, J. Parasitic diseases of rabbits. Merck Vet Manual 2021.
Terio, KA, McAloose, D, St. Leger, J. Pathology of Wildlife and Zoo Animals. 2018.
Photos 1-6 ยฉ Noahโs Arkive contributors Acland, Leathers, Jakowski, Reyes-Gomez licensed under CC BY-SA 4.0.
