Parasitic diseases in rabbits: the commonest threats and how to prevent them

Even when they are looked after with the greatest care, pet rabbits remain remarkably vulnerable to a wide range of parasites. Internal and external alike, these unwelcome guests pose a serious threat to a rabbit’s health: they can cause chronic digestive disease, neurological damage and, in the worst cases, death.

Every responsible owner benefits from understanding how the commonest parasites live, how they are detected and — most importantly — how infection can be prevented in the first place. This guide is a thorough reference on parasitic diseases in rabbits.

Internal parasites: a quiet and insidious enemy

Internal parasites are among the greatest challenges in rabbit care. Their presence is often difficult to spot until the infection has reached an advanced stage.

Coccidiosis

Coccidiosis is one of the most common and most life-threatening diseases of young rabbits. It is caused by protozoa of the genus Eimeria. Rabbits may be infected by several species, which attack either the intestines (the intestinal form, the more common of the two) or the liver (the hepatic form, which is rarer).

Infection occurs when a rabbit ingests oocysts shed in the faeces. The oocysts become infective within 24–48 hours and are extremely resistant to ordinary cleaning products. In young animals the signs come on rapidly and include severe watery or mucoid diarrhoea, lethargy, abdominal bloating, loss of appetite and rapid weight loss. The hepatic form leads to an enlarged liver and jaundice. Treatment calls for prompt administration of coccidiostats, often alongside supportive care such as rehydration and a change of diet.

Encephalitozoonosis

This is one of the most insidious diseases of all, frequently misdiagnosed or missed altogether. It is caused by a microscopic protozoan, Encephalitozoon cuniculi. The parasite targets mainly the nervous system (the brain) and the kidneys, and it can also colonise the lens of the eye. In most rabbits the infection is asymptomatic. When it does flare up, the signs are neurological: a head tilt (torticollis), nystagmus, ataxia (loss of coordination), seizures or paralysis. Other signs include kidney failure and ocular changes such as uveitis or cataract. Treatment involves giving fenbendazole over several weeks in order to curb the parasite’s replication and calm the inflammation.

External parasites: skin problems you can see

External parasites are either visible to the naked eye or announce themselves through obvious skin changes that an owner can easily notice while grooming.

Ear mange

This is the commonest parasitic skin problem in rabbits, caused by mites (Psoroptes cuniculi). It shows up as intense itching of the ears, head shaking and scratching. Thick, brown, flaking crusts resembling a shell build up inside the ear canal. Left untreated, ear mange is extremely painful, can lead to secondary bacterial infection and, in advanced cases, to a ruptured eardrum and neurological signs such as a head tilt. Treatment requires topical and systemic antiparasitic medication, for example selamectin or ivermectin as a spot-on. Never pick the crusts off yourself — you risk damaging the delicate ear canal.

Sarcoptic mites, cheyletiellosis, lice and fleas

Other mites call for treatment too. Burrowing mange mites (Sarcoptes/Notoedres) cause intense itching, hair loss and thickened skin, most often on the nose, lips and toes. Cheyletiellosis (Cheyletiella parasitovorax), on the other hand, is recognised by its “walking dandruff”: the mites move about beneath a layer of flaking skin, usually along the back. Lice and fleas are less common in rabbits than in dogs or cats, but they do occur. They need prompt treatment with suitable products — and you must never use preparations intended for dogs or cats without veterinary advice.

Diagnosis: the foundation of effective treatment

Getting the diagnosis right is crucial, because the signs of parasitic disease — the neurological and digestive ones in particular — are often non-specific. To reach an accurate diagnosis, a veterinarian uses the following laboratory methods:

A faecal examination means analysing samples under the microscope using flotation or a direct smear. A blood test shows whether the rabbit has been exposed to the protozoan, and a high antibody titre points to an active infection or a high risk of one developing. A skin scraping involves taking a small sample of surface skin and hair and examining it under the microscope to identify mites.

Prevention and routine care

The best defence against parasites is prevention. Rabbits are highly sensitive to change and to stress, both of which can wake up a dormant infection.

The essentials of prevention:

1. Environmental hygiene. Remove droppings and urine daily and change the bedding and hay regularly. Washing the hutch is not enough to disinfect against coccidia, whose oocysts are exceptionally tough. Use steam cleaning or specialist coccidiocidal products.
2. Quarantine and check-ups. Every newly acquired rabbit must spend at least three to four weeks in strict isolation from the rabbits already at home. Newcomers should have a faecal examination and a test for encephalitozoonosis, and preventive worming with fenbendazole is often recommended.
3. Diet and stress. Unlimited access to hay supports gut health and natural immunity. Keeping stress to a minimum matters enormously, since stress lowers immunity and allows latent disease to flare up.

The most common mistakes

Owners often make a handful of significant mistakes that can undo all the treatment and prevention:

• Using the wrong medication — for example products made for dogs or cats, which are toxic to rabbits (fipronil among them).
• Disinfecting incorrectly: if the product is not effective against coccidial oocysts, the disease returns quickly.
• Ignoring the environment — treating only the animal while leaving the hutch and accessories undisinfected.
• Stopping treatment too soon, which leaves the parasite alive.

Questions and answers

Responsible care depends on reliable information, so here are the answers to the questions we are asked most often:

• Does my rabbit need preventive worming? Worming is recommended for rabbits that go outdoors, mix with other animals or come from an unknown source. Oral fenbendazole is the usual choice, given preventively against encephalitozoonosis and certain roundworms. Always make the decision after talking it through with your veterinarian.
• Can I use flea products made for dogs or cats? Absolutely not. Many popular products are lethally toxic to rabbits. Use only what has been recommended by a veterinarian experienced in treating rabbits.
• How do I disinfect the hutch after coccidiosis? Clean the hutch thoroughly and disinfect it with products active against oocysts (sodium hypochlorite bleach solutions, for instance, or specialist coccidiocidal preparations). Be sure to rinse and dry the hutch completely before the rabbit goes back in.