Internal rabbit parasites

There are differing types of internal rabbit parasites that can be found in the intestinal tract, and elsewhere, in rabbits. Some are rare, others not so.

Internal rabbit parasites include worms (nematodes) and other microscopic organisms (protozoa).

Nematode adult worms consist of about 1000 cells of which hundreds are involved in reproduction. Parasitic nematodes (pinworms and oxyurid) are bacteria feeding round worms that live in the lower portion of intestines.

With early treatment, most parasite infections aren't life- threatening and worm invasion can be eliminated easily with medication.

Healthy house rabbits living in clean conditions are rarely affected, since the appropriate conditions are not present indoors for development of the larval stages. Thereby, if the rabbit is kept indoors 100% of the time, there is no problem.

However, most house rabbits are still let out in the garden, to run around or let into a run at some stage.

Many parasites are heteroxenous (multihost). This means that to reproduce they must live in several host intermediates before affecting the final host, in this case, the rabbit.

For example,, the different juvenile forms of the 'liver fluke' (fasciola hepatica) are found in particular types of snails in the grass of marshy areas, before entering the rabbits digestive tract.

The 'little fluke larvae' (dicrocoelium lanceolatum) need to live in snails and ants before becoming infective in rabbits. So these particular rabbit parasites are rarely found in house rabbits as their life cycle is broken owing to the lack of intermediate hosts in a house.

The other kind of parasite is single host (monoxenous). Their larval stages are usually found in wet grassland, stagnant water or hay, before being ingested by the final host, the rabbit. Such worms are more commonly found in rabbits.

They can cause loss of condition and ill health in rabbits and they can pose a risk to humans.

It’s not always easy to tell if your rabbit is infested as often there aren’t any outward signs of ill health. Coccidiosis, (single celled protozoa) is the most common of internal rabbit parasites, caused by the Eimeria species of protozoa, a microscopic parasite that invades the rabbit's liver or intestine.

The parasite multiplies and lays eggs in the faeces.

There are at least 4 species of coccidia that live in the intestines and one that grows in the liver.

Rabbits, like other animals, tolerate bacteria and worms and tolerate moderate numbers of some species of coccidia without showing illness, since not all species of coccidiosis are equally harmful. The Eimeria species invade the cells of the intestines, the Eimeria magna ,E media ,E perforans and E irresidua are the more dangerous types and result in diarrhoea, weight loss, dehydration and in extreme cases, are fatal, affecting younger rabbits worse.

E irresidua can cause severe tissue damage.

Eimeria stiedae is the one species that multiplies in the liver by entering the intestine wall and migrating to the bile duct where it reproduces. The species will cause damage to the liver and bile duct. The appetite decreases and a pot belly develops. Infection can be confirmed by the finding of the eggs (oocysts) in the faeces or the intestinal contents.

The parasites hatch out of their shell in the intestines and shed eggs in the host's faeces intermittently, so while one sample may show parasites, the next may not.

Ideally, several faecal samples would be collected at different times which would be negative (meaning no eggs are seen) before it can be sure that the parasites are really all gone.

However, a judgement has to be made whether the numbers of parasites present is sufficient to account for the disease problem as other disorders may produce similar signs.

Even if there are coccidia in a sample they may not be cause for an intestinal problem as most rabbits are infected without becoming sick.

Coccidia can live for years in untreated environment as they have protective cysts/capsules but can be killed by thorough cleaning.

Control of intestinal coccidiosis is mainly dependant on minimizing the dangers, (cleaning) such as the rabbits feed, water and living environment, hutches etc. If treating a rabbit for rabbit parasites, you need to clean/decontaminate and dry the rabbit's hutch/cage/litter areas thoroughly, as oocysts passed out in faeces need moisture and warmth to sporulate (release spores).

This cleaning needs to be done during the same period that the rabbit is receiving medicated treatment.

Good hygienic methods can eliminate coccidiosis or keep it to a low level.

Infected rabbits have to be separated from other rabbits until treatment is complete. It is important to prevent faecal contamination of feed and water and it is important to break the life cycle of the organism.

Young rabbits should be separated from others as soon as possible, since suckling rabbits are especially susceptible to coccidiosis. Rabbit parasites that may attack rabbits range from worms to protozoans (intracellular parasites). Protozoans are explained above.

Tape worms and flukes do not often cause problems to rabbits, neither do worms in the droppings, which are treated for aesthetic reasons as much as anything else.

If infected, tapeworm segments could be seen in faeces or near the rabbit's anus. Rabbits are infected with tapeworm by swallowing fleas while grooming. Once inside the rabbit’s gut, the worm larvae carried by the flea develops into an adult worm.

All of these rabbit parasites can be treated easily with de-worming medications.

Rabbits become infested by eating fresh grass that has mites or ants on it (for tapeworms) or snails (for flukes).None of these parasites can infect humans.

However, pets like dogs and cats often carry parasites that cause blindness in children, skin problems, and potential birth defects, as well as illness in rabbits and other pets. For public health reasons and the safety of your rabbit, if you also have dogs or cats they need to be de-wormed and have their stools checked regularly. Cats hunting outdoors are a definite problem.

To prevent worm invasion and rabbit parasites, forage or greens from the garden, should not to be given to rabbits from areas where there are dogs cats or the possibility of rodents.

All forage, fresh greens and vegetables must be washed thoroughly.

Bedding , litter area, hay and, if given, straw should be changed daily.

If hay is not changed daily, it should be given on a feed rack, in this way the hay will not be soiled with faeces or urine.

Such worm invasion can be eliminated easily with medication.

A common parasite called Encephalitozoon cuniculi (E. cuniculi). is caused by a microscopic parasite and is common in the UK.

Figures of rabbits exposed to this parasite suggest that it may as high as 50%. The disease is particularly nasty. It often causes a rabbit’s head to tilt on one side and perhaps twisting backwards. It can also cause seizures, loss of balance or seem that the rabbit is having a fit. Other effects can be kidney disease, hind limb weakness or loss of vision.

The parasite spreads by way of infected urine or from a mother rabbit to the baby and it can live in the environment for several weeks.

For this reason areas/hutches/runs that contain a large number of rabbits, are often infected.

In colour, roundworms are pale white to beige and are coiled like a spring in appearance. They grow to approximately 4"(10cm) in length and the first you may be aware of the problem is when you see them in your rabbit’s faeces.

Rabbits pick up roundworms by eating their larvae and the adult worm then develops inside the body with worms and eggs being passed out in faeces.

These eggs develop into larvae and the cycle starts over again.

All rabbit parasites are treatable and a visit to the vets will help to work out the correct medication.