Parasites in Rabbits

Parasitic diseases are a major health concern for pet rabbits. While internal worms are uncommon, rabbits are frequently affected by external mites and a debilitating internal protozoan parasite called Encephalitozoon cuniculi. These parasites can cause conditions ranging from intense itching and fur loss to severe neurological damage.

External Parasites

1. Ear Mites (Psoroptes cuniculi):

   • Cause: This is a common and very painful mite infestation of the ear canal.
   • Signs: The hallmark sign is the presence of a thick, crumbly, brownish crust inside the ear. The rabbit will be in significant pain, shaking its head, and scratching at its ears. If left untreated, the infection can lead to hearing loss and spread to the middle and inner ear, causing a head tilt.
   • Action: This requires a veterinary visit. Do not attempt to clean out the crust yourself. This is extremely painful for the rabbit. A vet will prescribe medication (like ivermectin or selamectin) that will kill the mites, after which the crust will resolve on its own.

2. Fur Mites (Cheyletiella parasitovorax and Leporacarus gibbus):

   • Cause: These mites live on the skin and in the fur. Cheyletiella is often called "walking dandruff" because you can sometimes see the mites moving in the flaky skin.
   • Signs: The most common sign is a large amount of white, flaky dandruff, particularly over the shoulders and back. This may or may not be accompanied by itching and hair loss.
   • Action: A vet will diagnose the mites and prescribe a safe and effective anti-parasitic medication. As with ear mites, over-the-counter products should be avoided.

Internal Parasites

Encephalitozoon cuniculi (E. cuniculi):

This is a microscopic protozoan parasite that is a leading cause of neurological disease in rabbits. It is extremely common, and it is estimated that a high percentage of pet rabbits have been exposed to it. The parasite primarily affects the kidneys and the brain.

• Transmission: The parasite is shed in the urine of an infected rabbit. Other rabbits become infected by ingesting food or water contaminated with the spores.
• Signs: Many rabbits are asymptomatic carriers and never show signs. In those that do, the signs are typically neurological:
  • Head Tilt (Torticollis): This is the classic sign. A persistent and often severe tilt of the head to one side.
  • Loss of Balance: The rabbit may circle, stumble, or be unable to stand.
  • Eye Movement: Uncontrolled, rapid eye movements (nystagmus).
  • Hind Limb Weakness: Dragging of the back legs.
  • Urinary Incontinence: Dribbling urine.
• Action: Diagnosis can be challenging and is often based on clinical signs and blood tests. Treatment involves a 28-day course of an anti-parasitic medication called fenbendazole (Panacur). Supportive care is also critical to help the rabbit with balance and to ensure it continues to eat.

Prevention

• Quarantine: All new rabbits should be quarantined for 30 days and seen by a vet before being introduced to other rabbits.
• Good Hygiene: Keep the cage and litter box clean to prevent the spread of E. cuniculi spores.
• Reputable Source: Obtain your rabbit from a source that practices good parasite control.
• Preventative Treatment: Some vets recommend a prophylactic course of fenbendazole for newly acquired rabbits, especially if they will be housed with other rabbits.

Due to the serious nature of these common parasites, any rabbit showing signs of itching, hair loss, or any neurological abnormalities should be seen by a rabbit-savvy veterinarian immediately.