Coccidiosis is one of the most important causes of diarrhea, poor growth, and sudden death in young rabbits. It is caused by microscopic parasites called Eimeria that infect either the intestines or the liver. Weanling rabbits between roughly four and twelve weeks old are by far the most vulnerable, especially in crowded or unsanitary conditions, while many adult rabbits carry low levels without obvious illness. The classic signs are diarrhea, a bloated belly, poor weight gain, and lethargy. Because young rabbits can crash quickly, any baby rabbit with diarrhea should be treated as urgent.
Last reviewed: June 2026
What Coccidiosis Is
Coccidiosis is an intestinal or hepatic infection caused by single-celled Eimeria parasites. Rabbits pick up the parasite by ingesting infective oocysts shed in the droppings of infected rabbits, often from contaminated food, water, or bedding. There are two main forms. Intestinal coccidiosis, caused by several Eimeria species, damages the lining of the gut and causes diarrhea and malabsorption. Hepatic coccidiosis, caused by Eimeria stiedae, infects the bile ducts of the liver. As described in Quesenberry & Carpenter's Ferrets, Rabbits, and Rodents, young, recently weaned, and stressed rabbits in high-density environments are at greatest risk, and overcrowding and poor hygiene dramatically increase the parasite load.
The Signs of Intestinal and Liver Forms
The signs depend on which form is present and how heavy the infection is. Intestinal coccidiosis typically causes diarrhea or soft, mucousy droppings, a bloated or painful belly, poor appetite, weight loss or failure to grow, dehydration, and lethargy; severe cases can be rapidly fatal in young rabbits. Hepatic coccidiosis is often quieter, causing poor growth, a pot-bellied appearance, weight loss, and sometimes jaundice or a swollen abdomen from an enlarged liver, and it may go unnoticed until the rabbit is quite ill. Because not eating and gut slowdown are so dangerous in rabbits, the metabolic risks of anorexia compound the problem (Oglesbee & Lord, 2010, JEPM).
How It Is Diagnosed and Treated
A vet diagnoses coccidiosis by examining a fecal sample under the microscope for the characteristic oocysts, and the liver form may be suspected from blood work showing liver changes plus imaging. Treatment uses anticoccidial medications, commonly a sulfa-based drug or toltrazuril, given for a course to bring the parasite under control, along with crucial supportive care: fluids for dehydration, syringe feeding to keep the gut moving, and pain relief. According to the AEMV exotic pet care resources, supportive nursing is as important as the antiparasitic drug itself, because the secondary effects of dehydration and anorexia are often what kill young rabbits (AEMV Pet Care Guides, 2024). Severely affected babies may need hospitalization.
Preventing Coccidiosis
Prevention centers on hygiene, because the parasite spreads through contaminated droppings. Keep enclosures clean and dry, remove droppings frequently, and use elevated or easily cleaned flooring so rabbits cannot constantly re-ingest oocysts from soiled bedding. Avoid overcrowding, which drives up both stress and parasite load, and minimize stress around weaning. Quarantine and fecal-test new rabbits before introducing them to your group, and disinfect housing thoroughly, since the oocysts are hardy in the environment. Provide a proper hay-based diet and clean water to support gut health and a strong immune system. Any new young rabbit with diarrhea should be tested promptly so coccidiosis can be caught before it becomes severe.
When to See a Vet
Call your vet today if:
- A young rabbit has diarrhea, soft droppings, or a bloated belly
- Your rabbit is not gaining weight or appears pot-bellied
- You notice reduced appetite, lethargy, or a rough coat in a weanling
- A recently acquired rabbit develops loose stool
- Multiple rabbits in a group are showing similar digestive signs
Go to the ER immediately if:
- A young rabbit has watery diarrhea and is weak, cold, or collapsing
- Your rabbit has stopped eating entirely and is producing no droppings
- There is severe lethargy, dehydration, or a distended painful abdomen
- The gums are pale and the rabbit is unresponsive
- A baby rabbit deteriorates rapidly over a few hours
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Frequently Asked Questions
What are the first signs of coccidiosis in rabbits?
The earliest signs in young rabbits are usually diarrhea or soft, mucousy droppings, a bloated belly, reduced appetite, and poor weight gain. Affected babies often look rough-coated, lethargic, and pot-bellied. The liver form can be quieter, showing mainly poor growth and weight loss. Because young rabbits decline fast, any weanling with diarrhea or a swollen abdomen should be tested and treated promptly rather than watched.
Is rabbit coccidiosis contagious to other rabbits or pets?
Coccidiosis spreads readily between rabbits through droppings, so an infected rabbit can pass it to others sharing the same space, especially in crowded or dirty conditions. The Eimeria species that infect rabbits are host-specific, so they do not infect dogs, cats, or people. If one rabbit is diagnosed, clean the environment thoroughly, and your vet may recommend testing or treating in-contact rabbits.
How much does it cost to treat coccidiosis in a rabbit?
An exotic vet exam typically runs $75 to $200, with a fecal test adding $30 to $80. Anticoccidial medication for a treatment course usually costs $30 to $100. A severely affected young rabbit needing hospitalization with fluids and syringe feeding can run $300 to $1,000 or more. Because exotic care carries a premium, prompt treatment of mild early cases is far cheaper than an intensive rescue.
Can adult rabbits get coccidiosis?
Yes, but adults are usually far more resistant than young rabbits and often carry low levels of the parasite without obvious illness. Disease tends to appear in weanlings, stressed rabbits, or animals in crowded, unsanitary conditions where the parasite load builds up. An adult rabbit that becomes sick with coccidiosis may have an underlying stressor or immune problem, which is worth investigating with your vet.
How do I prevent coccidiosis in my rabbits?
Keep housing clean, dry, and uncrowded, remove droppings frequently, and use flooring that prevents constant re-ingestion of oocysts from soiled bedding. Reduce stress, especially around weaning, and quarantine plus fecal-test any new rabbit before mixing it with your group. Thorough disinfection matters because the parasite eggs are hardy. A good hay-based diet and clean water support gut health and immune resistance.
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