Did you know that rabbits are the third most popular pet in the UK?

As SQPs, a rabbit’s health is something we advise our customers on all the time; whether it’s  promoting products for disease prevention (and subsequently advising our clients on the best products to use and the dosage rates) to discussing parasite control as an important step in helping to keeping rabbits healthy and to avoid any other significant health problems, such as against blowfly, mites, fleas and worms (with some of these parasites zoonotic to humans). But in rabbits, there’s only one internal parasite we really tend to focus on.

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What is E. cuniculi?

E. cuniculi is caused by a microsporidian – a single-celled organism very similar to a protozoa – with the full name Encephalitozoon cuniculi. Affecting the nervous system and the kidneys, E. cuniculi is spread between rabbits via urine, or during pregnancy. In kits infected while still in the uterus, eye signs may develop as they reach early adulthood. 

A hardy parasite, E. cuniculi can survive for extended periods in the environment. Although infection from the bunny’s mother is the most common route of infection. 

The most frustrating aspect of E. cuniculi is its unpredictability. More than half of all rabbits have antibodies to the parasites. This means at some point in their lives they have been exposed to the spores. Thankfully, the actual numbers of rabbits who suffer with signs of clinical infection are much lower than this. But this means it can be incredibly difficult to prevent rabbits being exposed, or to predict which rabbits will show signs of infection.

It is worth remembering too that the parasite is infectious to humans (although clinical infection is very rare). And potentially to other species such as dogs, although disease is very unlikely. The main route of infection is via urine, so good hand hygiene when cleaning out bunny enclosures is advised.

What are the signs?

The signs of E. cuniculi vary depending on the rabbit, along with the severity and route of the infection. Signs can include:

  • Back leg weakness
  • Paralysis
  • Head tilted to one side
  • Falling over/rolling
  • Fits
  • Increased thirst and urination
  • Weight loss
  • Cataracts

It is worth noting that most rabbits show no signs of an infection at all, and conversely some acutely infected animals can die rapidly. It is thought that periods of stress can cause rabbits who are infected and showing no signs to start being ill.

How can it be prevented?

With the likelihood of E. cuniculi infection being so high, and the risk of infection already having occurred from your rabbit’s mother, it is impossible to completely protect your rabbit from this parasite. The best ways to protect your rabbit are:

  1. Stable environment. Whilst being kept alone would technically be safer, we do not recommend keeping rabbits alone as their welfare can be severely impacted. Stable groups are best in terms of disease management, and for the general health and behavioural health of your rabbit.
  2. Monitoring. If you see any changes in your rabbit’s eating and drinking habits, balance, or eyes, then always get them checked over by a vet, who will be able to help diagnose and support them.
  3. New friends. If you want to introduce a new rabbit to your group, consider a quarantine period before the new friends are allowed to mingle. During this time, give all your rabbits a course of medication against E. cuniculi. Do not forget, your own rabbits may have a silent infection, which can flare up with the stress of a new addition to the family.
  4. Cleanliness. Routine disinfectants should kill off any E. cuniculi, so make sure to clean your rabbit’s areas thoroughly.

What else can we do?

There is a medication available, that does not need a prescription, and is designed to be used for the control and treatment of E. cuniculi. This product belongs within the Small Animal Exemption Scheme; this is a category of medicines that are produced for small animals without the requirement for a full pharmaceutical licence.

Containing the active ingredient Fenbendazole (0.187gm per 1gm), Panacur Worming Paste for Rabbits is administered orally by squeezing the paste from the syringes provided into the side of the mouth. One syringe graduation per 2.5kg bodyweight should be administered daily for nine consecutive days for prevention.

It is usual practice to advise owners to give an anthelmintic as a preventative measure, I would recommend two to four times a year in high-risk animals, including when the rabbit is brought, prior to mating and when mixing with other rabbits. However, not all rabbits will need treating all the time – so you should always start by talking to your vet or SQP.

If a customer has any concerns about their rabbit or rabbit health then it is important that a veterinary surgeon checks it to make sure there are no further health problems.

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Further Reading