Rabbits – Common Illnesses

Abstract This Veterinary Nurse CPD lecture takes a look at rabbit health and the common illnesses of rabbits. It discusses health concerns such as gastro-intestinal stasis, dental disease, flystrike, arthritis, and many more, and looks at both symptoms and treatment of them.

Learning outcomes

Knowledge of the symptoms of a variety of common rabbit illnesses

Knowledge of the treatment of a variety of common rabbit illnesses.

Course Notes

Basic Rabbit Biological information Bodyweight (kg): 1.5-10 (Netherland Dwarf – New Zealand White) Rectal body temperature (ºC): 38.5-40 Respiratory rate at rest (breaths/min): 30-60 Heart rate at rest (beats/min): 130-325 (New Zealand White – Netherland Dwarf) Gestation length (days): 29-35 (average 31) Litter size: 4-10 Age at sexual maturity (months): Males = 5-8, Females= 4-7 Lifespan (years): 6-10 (sometimes into teens) Water intake per 24hr (mls): 80-100ml/kg

Gastrointestinal stasis When a rabbit’s digestive system is compromised, either due to illness, pain or stress, then their hydration and food intake is likely to be reduced. This causes a reduction in the gut motility. Rabbits are unable to go any significant amount of time without food in their digestive system. If a rabbit stops eating or reduces its food intake then the gastrointestinal tract will go into stasis or ileus, where it slows down or comes to a complete standstill. This in itself can prove fatal within just a matter of hours. A rabbits diet Rabbits require a high-fibre (+25%), moderate protein (12-13%) and low carbohydrate diet in order to maintain optimum gastrointestinal function. The majority of pet rabbits are overfed on concentrated mixes and don’t eat enough hay and grass which should make up the majority of a rabbits daily food intake. Added to this that rabbits who are fed a mix and pick out their favourite pieces of food, which often contain high levels of sugar and minimal amounts of fibre, often suffer with dental problems and GI stasis episodes. Selective feeding can be prevented by changing the rabbit onto either Burgess Excel or Supreme Selective. Both of these are extruded nugget type feeds that prevent selective feeding. Both are high in fibre and contain the correct amount of protein and carbohydrate in order to maintain good GI tract health. The average size pet rabbit should have an egg-cup full of concentrated food, unlimited amounts of hay and grass and a mound of fresh vegetables their own body size each day. Treats, such as those bought from pet shops, should be avoided.

A rabbits digestive system A rabbits digestive system is designed never to be empty and constantly contains food, caecal pellets and hair ingested during grooming. Fur-blockage is still thought, by some vets, to be a primary cause of GI stasis, but in truth it is normal to find some hair in a rabbits digestive system. Problems occur when the hair dries out due to a decrease in appetite and hydration and as such should be treated as a secondary problem due to the stasis and not a primary cause of stasis. The exception to the rule may be in long-haired rabbits, where true fur-blockage may be a primary cause of GI stasis. The colon is responsible for sorting digestible and indigestible fibre. The rabbit eliminates the indigestible fibre as the hard; round droppings as these have no nutritional value to the rabbit. The digestible fibre components are moved into the caecum where microbial digestion takes place. The digestible fibre is excreted in the form of caecotrophs; small, clumps of smelly droppings covered in mucous. These are usually eaten directly from the anus by the rabbit and contain amino acids, fatty acids and vitamins B and K, from previously undigested foods. Consumption of the caecal pellets is important for the GI tract and overall health of the rabbit. The mucous protects the caecal pellets from the acidic pH of the rabbits stomach. What goes wrong? There are many potential reasons for a rabbit to reduce or cease eating and drinking, and are just some of the more common causes: Dental problems causing pain Illness Not enough fibre in the diet Dehydration Toxins Foreign body Stress from the loss of a partner, a sudden change in diet, a change in the environment or transportation, extreme heat or cold or being around a predator. Symptoms Normally the symptoms will have a gradual onset and owners may notice the rabbit eating slightly less, being slightly less active and perhaps see droppings that are strung together on hair and the rabbit producing less droppings. The symptoms may gradually worsen over the coming week or so, until the rabbit may completely stop eating and drinking altogether, pass no droppings at all and not want to move. The rabbit may also grind its teeth in pain (bruxism). Treatment Treatment needs to be started immediately and in an aggressive form. A blood glucose should be taken. Rabbits increase their blood glucose when placed under physical stress and a high blood glucose is a strong indication for a foreign body blockage requiring immediate surgery. A drop of blood can be taken from the marginal ear vein analysed on most glucometers, under a cat or dog setting.

<4.2mmol/l – Low and needs further investigations and nutritional support

4.2-8.2mmol/l – Normal

8.3-15mmol/l – The rabbit is stressed and likely anorexic. Will need supportive treatment

15.1-20mmol/l – Likely to have been anorexic for some time. Aggressive supportive treatment is required

Above 20mmol/l – Life-threatening disease with a poor prognosis and possibly a surgical case if other clinical factors also indicate (these are normally intestinal blockages).

If a blockage is not indicated then aggressive medical treatment should be started. The rabbit should be syringe fed or an oesophageal feeding tube fitted if the rabbit is unwilling to take syringe feeds; aim for 20-50ml/kg per day, split into several, regular feeds. Offering tempting foods, such as freshly picked grass, fresh greens and sweet smelling hay may encourage the rabbit to begin eating again. Medications to kick-start the GI tract (prokinetics) should be commenced and intravenous fluid therapy should also be started. Pain relief (analgesia) must also be included in the treatment regime as rabbits who are in pain will not eat. If a blockage of some description is suspected then this much be ruled out before any prokinetic medications are given. If the rabbit is treated at an early stage (i.e. within a couple of hours of not eating), then the prognosis for recovery is good. If treatment is delayed for a number of hours then a full recovery is less likely. Some rabbits may take several days of treatment before any improvement is seen, so it is worth persevering with treatment if the rabbit can be kept comfortable during its recovery. Finding a cause It is all very well and good treating the GI stasis but the route of the primary cause needs to be identified and addressed to stop the rabbit suffering from another episode. This may include a thorough dental examination, looking at the rabbits housing and social status, examining the diet, and looking back over recent events to see if a stressful occurrence can be identified.

Flystrike Vets know that with the arrival of the warmer months, comes the common problem of rabbits affected by flystrike being presented to them. This is a deeply distressing condition for owners, the veterinary team and especially the rabbit, which is literally being eaten alive. What is flystrike? Certain species of flies (e.g. bluebottles), use other animals as a host to lay their eggs on, which hatch into maggots, and then proceed to eat into the flesh of the animal, causing immense suffering to the animal, which in essence is ‘eaten alive’. Flies are attracted by soiled or wet fur, usually around the tail area of the rabbit, but any area can be affected, or any open wound, cut or scratch. Once laid, the eggs will hatch into maggots within 12-36 hours, burrowing into the rabbits flesh, causing vast tissue damage and pain, which can prove to be fatal even with prompt veterinary treatment. What time of year does flystrike affect rabbits? The months of April to October are quoted as being the months when animals are more susceptible to flystrike, but it has been reported to have occurred in rabbits as early as January or as late as November, so owners need to be vigilant throughout the whole year, but extra vigilant during the ‘flystrike season’ of April to October.

What rabbits are affected by flystrike? Any rabbit, even those kept as houserabbits who keep themselves beautifully clean, can be affected by flystrike; it only takes one area of soiled fur/skin or scratch, and one fly. However, not surprisingly those most at risk are rabbits who have frequent dirty bottoms, so ensuring that rabbits are clean and dry is the best prevention against this awful condition. Possible causes of dirty bottoms include: Dental disease – making cleaning too painful Spinal problems – making cleaning difficult or painful or causing difficulty in adopting the correct position to eat the caecotrophs (normal soft droppings produced by rabbits which are eaten direct from the anus as they are produced) Balance problems – unable to adopt the correct position to clean themselves Obesity – too fat to reach their bottoms to keep clean or retrieve the caecotrophs Incorrect diet – leading to too many caecotrophs being produced Too much dried food – filling up on this and so not hungry enough to eat the caecotrophs, which then get left and stuck to the tail area Old age – not able to keep themselves clean Other ‘High Risk’ categories Longhaired rabbits are also more susceptible to flystrike, because of the amount of fur they have and faeces are more likely to get caught up in the fur, and as aforementioned any bloodied area (cuts or wounds etc) will also attract flies. Preventing flystrike As far as flystrike goes, prevention really is better than cure and can not be stressed enough, and even if a rabbit isn’t classed as being at ‘high risk’ of developing flystrike, it is still imperative you still do as much as you can in preventing them from contracting it – low risk, doesn’t mean no risk. Ways on trying to prevent flystrike include: If possible, treat any condition which places the rabbit in a ‘high risk’ category Ensure that the rabbit isn’t overweight and is fed a correct diet Check the whole rabbit, paying special attention to the back end and tail area, at least twice a day, going through the fur to check for soiled/wet fur or maggots If the rabbit has a dirty bottom, clean it for them immediately High risk rabbits may be safer inside the house, but must still have their bottom checked twice daily Clean litter trays daily and remove all soiled bedding from hutches daily Staple net curtains over the hutch/run to insect proof them Consider using ‘Rearguard’. Produced by Novartis Animal Health, Rearguard is a liquid which is applied to the tail area of the rabbit by sponge, and should any eggs be laid on the area it will prevent them from hatching into damage causing maggots When rabbits get flystrike You may not be able to see any actual maggots as they may be concealed under matted or soiled fur (especially in long-haired rabbits), so if a rabbit is displaying symptoms such as restlessness, irritation around a certain area (usually the tail area), lack of appetite, sudden aggression etc, they should be taken to a vet immediately – this is an emergency and can not wait until the following day. If owners can see any obvious maggots remove them with tweezers as quickly as possible, but do not put the rabbit into water in an attempt to wash off some of the maggots.

Clippers don’t work very well on wet fur and you may be delayed in treating the rabbit if you have to dry the fur first. The longer a rabbit is left the more damage the maggots will cause, which may be impossible to treat, with the only option of putting the rabbit to sleep, to stop it suffering any longer, so time really is of the essence. Is flystrike treatable? Cases of flystrike can be successfully treated if caught early, but this is dependant upon the amount of damage caused by the maggots and if it is thought that the rabbit has a reasonable chance of recovery. Treating flystrike Treatment normally consists of: Clipping the fur from the affected area to assess the damage Washing and removing all visible maggots Surgery to remove any concealed maggots, necrotic (dead/infected) tissue and repair tissue damage Antibiotics to prevent a secondary infection or treat infection if one is already present Identifying the cause as to why the rabbit was affected with flystrike and treatment to correct any underlying problem Analgesia and supportive treatment (syringe feeding, intravenous fluids and prokinetic medications). Rabbits will need to be anaesthetised for surgery and often rabbits affected with flystrike are suffering to some degree with shock, and will carry a higher anaesthetic risk. If the rabbit does survive, the wounds can take weeks to heal and during this time the rabbit will be at an increased risk of further bouts of flystrike and also infections, so careful nursing by the owner will be required and preventative treatment measures must be stepped-up.

Dental problems Rabbits teeth are open-rooted, so grow continuously throughout life. If the rabbit has congenital or acquired dental disease, then the teeth may overgrow, which can cause life-long problems. Rabbit teeth Rabbits have four upper incisors and two lower incisors. These are used to hold food in the mouth as it is passed to the pre-molars and molars for chewing. Unlike dogs and cats, rabbits do not have any canines, but have a gap where the canines would be. This is called the diastema. Rabbits also have ‘peg’ teeth. These are small teeth that sit directly behind the upper incisors. The upper jaw contains six cheek teeth, consisting of three premolars and three molars on each side. The lower jaw contains five teeth on each side; two premolars and three molars. The incisors grow approximately 2-3mm per week with the cheek teeth growing at this length every month. Rabbit teeth function Wild rabbits live on grass and more grass. The constant abrasive chewing action means that without having open rooted and therefore constantly rowing teeth, wild rabbits teeth would quickly wear down and the rabbit would starve to death from being unable to chew food.

Domestic, pet rabbits teeth act in exactly the same way, but pet rabbits differ from wild rabbits in the diet they are fed and the breeds and different head shapes that they come in. Wild rabbits have slim, long heads, whereas many breeds of rabbits are brachycephalic. This can mean that the rabbits teeth are squashed together and don’t align properly. What goes wrong? There are several things that can go wrong with pet rabbits teeth. Firstly, dental disease is often congenital, so rabbits who are bred from parents who have dental problems or known problems in the breeding line, are likely to inherit the problem. This type of malocclusion is normally apparent by the age of 9-18 months and normally requires life-long treatment in order to keep the rabbit comfortable and eating. Trauma is another potential trigger for dental disease. Rabbits who are dropped and bang their mouth or may pull on the wire of their hutch/enclosure are prone to traumatic dental disease. This type of malocclusion can sometimes be cured through burring the teeth (normally the incisors) at regular intervals until they grow correctly again. This may take several months and it is not always possible to cure the problem. Incorrect or poor diet is the most common reason for malocclusion. Rabbits need a high fibre, abrasive diet in order for adequate gut function and dental wear. Without it their teeth quickly overgrow. A rabbits diet should consist of at least 80% grass/hay, with a small amount of an extruded nugget type food to prevent selective feeding, and a daily portion of greens and vegetables. Selective feeding This is a big problem with rabbits and many owners are still unaware of it. Rabbits who are allowed to selectively feed will pick out the pieces of their rabbit mix that they like and leave the rest of it. Over time the rabbit becomes deficient in calcium and the teeth work lose from their sockets. Even the smallest movement of the teeth in the sockets will stop correct alignment and the teeth will develop sharp spurs, which cut into the tongue and cheeks. It is therefore imperative that if owners feed a muesli type dried food they should consider swapping their rabbit onto an extruded nugget type food to prevent selective feeding. Clinical signs and treatment options Rabbits may just suffer from malocclusion of the incisor teeth, in which case burring the teeth as and when necessary (normally monthly) will stop them overgrowing. Never allow anyone to clip rabbits teeth with nail clippers or any other type of clipper. The pressure that is put onto the tooth during clipping is likely to crack and split the tooth down in the root, which often sets up a tooth-root infection, which can be impossible to treat (see osteomyelitis). Overgrown incisors are a hindrance to the rabbit and they are better off having them surgically removed. Rabbits adapt perfectly well to having no incisors, as they begin to use their lips to hold and pick up their food. Molar and premolar malocclusion is more complicated. Often a rabbit may begin with incisor malocclusion and as the jaw is pushed out of alignment, the molars and premolars will overgrow. This type of dental disease will show as the rabbit going off certain foods (sometimes hard foods, sometimes softer ones), the rabbit may salivate and have a wet chin or matted inside front paws where they have been wiping their mouth. Weight loss may occur if the problem

develops slowly and the rabbit may become depressed. Discharge from the eyes may appear if there is elongation of the upper tooth roots and they are impinging on the nasolacrimal ducts. Rabbits with cheek teeth dental disease require sedation or general anaesthesia on a regular basis in order to remove any sharps edges or overgrowth of the teeth. This can need repeating as often as monthly for the rest of the rabbits life, so it is a serious financial commitment by the owner and potential problem for the rabbit. Dental disease investigation Radiography of the skull is recommended with all dental disease, in order to assess the tooth roots which can often overgrow. If you feel along a rabbits lower jaw you may feel bumps and upper tooth roots can in severe cases grow into the eye sockets. Cheek teeth can be removed if they are problematic, growing at the wrong angle, harbouring infection or the roots are showing overgrowth. Often, this requires referral to a more experienced exotic vet for this type of surgery. Osteomyelitis Facial abscesses are common in rabbits and are associated with bony structures in the skull. They carry a very poor prognosis since they are often impossible to surgically remove and wall themselves off; making getting any form of systemic antibiotics to the site impossible due to the poor blood supply. Some vets may try mauka honey treatments or impregnated antibiotic beads to slowly release antibiotics directly at the abscess site over a period of time, but more often than not the treatment will fail to resolve the problem. If the rabbit is pain free or its pain can be managed successfully, it is eating and drinking and has a good quality of life, then sometimes rabbits can live perfectly happily with such abscesses for many months/years, but if the rabbits quality of life can not be maintained then euthanasia is the kindest option. Dental disease in rabbits is a complicated and often preventable problem. Always ensure rabbits are fed a good diet to try and prevent problems manifesting.

Pododermatitis Pododermatitis, often referred to as sore hocks, is when sores appear, commonly on the back of the hock, but can occur on the forefeet if the rabbit adjusts its stance putting more pressure on the forefeet. Often the condition starts as a small pink, bald patch and can rapidly worsen into full blown open sore, which is left untreated can proceed into the bone. Causes Rabbits who are overweight, giant breeds, Rexes who have a thinner hair covering on the soles of their feet, arthritic rabbits who may have an unusual gait and rabbits kept in unsanitary conditions where they are forced to sit in urine and faeces, are all prone to this condition. House rabbits are also thought to be more commonly affected due to the carpeted areas they often live on and the abrasive effect this can have on the feet.

Treatment The underlying cause/s needs to be determined and corrected to help prevent the condition from worsening and reoccurring. Weight loss may be required, a change in environment, change of bedding to allow for extra padding. Bandages may be required to help protect the sores. Topical creams can also be applied to help with the soreness although rabbits may rapidly lick these off. The rabbit needs to be kept on soft, absorbent bedding (such as vetbed) to help cushion the feet. The condition can progress to such a stage whereby euthanasia is required. If infection is present than antibiotics are indicated and since these sores can be extremely painful the rabbit will require analgesia. If they are anorexic then syringe feeding, fluids and prokinetic medication is also indicated. The condition can be difficult to treat and requires owner compliance.

Encephalitozoon cuniculi Encephalitozoon Cuniculi (E. cuniculi) has been one of the hottest topics in rabbit health over the past few years. It's also remains one of the most controversial! Knowledge is constantly evolving and whilst some opinions differ on how serious the parasite is, there are many things we now know about it. We know that E. cuniculi infection is very common in apparently healthy pet rabbits (a survey showed 52% of clinically healthy rabbits had been exposed to the parasite), and that it can cause a host of clinical symptoms. What is E. cuniculi? It's a parasite - a small protozoan that lives inside the body cells of its host. It doesn't just infect rabbits: cases have been reported in sheep, goats, dogs, cats, monkeys, guinea pigs, foxes, pigs and humans. It is a recognised zoonosis (disease which can be transmitted to humans), but the zoonotic risk seems to be negligible to healthy individuals observing basic hygiene. How common is E. cuniculi in pet rabbits? A major research project run in 2006 by veterinary surgeon, Emma Keeble at Edinburgh Vet School (and supported financially by the Rabbit Welfare Fund), set out to determine what percentage of 'healthy' British pet rabbits that have exposed to E. cuniculi. The results of the project found that 52% of apparently healthy rabbits had been exposed to E cuniculi infection. The rabbits used in the study were blood tested at the time of neutering and showed no clinical symptoms of an E. cuniculi infection. It is not known what percentage of the positive rabbits went on to develop any health problems associated to the parasite. How do rabbits get infected with E. cuniculi? A lot of rabbits are infected in the womb via the placenta (transplacental infection). The other route of infection is orally via ingestion of urine contaminated by E. cuniculi spores. One month after infection, a rabbit will start to shed spores in its urine. Shedding of spores continues for up to three months and possibly on and off for life. The spores are tough and remain in the environment for more than a month.

What happens when a rabbit becomes infected? When a rabbit is first infected, the parasite is absorbed from the intestines. Once inside the body, it heads off to other ‘target’ organs, especially the kidneys and brain, where it causes granulomas. These can be found in the kidneys of rabbits only a few months old. Granulomas may develop in other parts of the body, such as the liver, as well as in the brain. The infection may remain in a dormant phase for months, years or never cause the rabbit any problems throughout its life. Stress, either physical or psychological seems to be a major trigger factor in the infection becoming active and causing clinical signs. What kind of problems can E. cuniculi cause? Renal (kidney) granulomas may lead to chronic renal failure with problems such as increasing thirst and weight loss. However, it's the lesions in the brain that tend to cause problems. The range of possible neurological presentations are immense but some examples are:

Convulsions (fits)

Tremors

Torticollis (head tilt)

Hind limb weakness (ataxia)

Coma or even death

Urinary incontinence (caused by the central nervous system lesions, not those in the kidney).

Loss of balance E. cuniculi can also affect the eyes. If unborn baby rabbits become infected via the placenta, granulomas may develop around the lens and cause problems after birth such as Uveitis (inflammation of the Uvea of the eye). Affected rabbits sometimes have white patches visible in the eye. One of difficulties in trying to decide whether E. cuniculi is the cause of any specific problem is that every one of these problems has other possible causes and therefore a definite diagnosis is often not possible to be certain of by clinical signs alone. How would I know if a rabbit has E. cuniculi? Antibodies to E. cuniculi can be detected on a blood test. Hence, a rabbit that has been infected to E cuniculi will produce antibodies that will produce a positive test. However, some rabbits appear to clear the infection completely and over time their blood test will become negative again. A negative result basically rules out E. cuniculi as the cause of the illness, but it is wise to repeat the bloods after 4 weeks to ensure the first blood sample wasn’t taken too early in the disease process as the rabbit may not have seroconverted and begun producing antibodies. If a second blood test is negative then this rules E. cuniculi out as the cause of disease. Some laboratories are now able to offer a more comprehensive test is to measure two stages of the antibodies, known as the IgG and IgM levels. The IgM level is the first to be produced after infection. This will begin to decrease as the IgG level increase, which is the long term response for immune status. Two blood samples 4 weeks apart should be taken so the results can be compared to look for a rising titre indicating active infection and a diagnosis of E. cuniculi. Treatment for E. cuniculi If a diagnosis of E. cuniculi is confirmed or strongly suspected then the standard treatment is with Fenbendazole (Panacur), once daily for 28 days at a dose rate of 20mg/kg. This aims to kill the parasite. However, the rabbits clinical signs may or may not improve, since the inflammation in the brain caused by the parasite may be irreversible.

Depending upon the rabbits clinical symptoms, they may require syringe feeding, fluid therapy, prokinetic medication, antibiotics and analgesia to support them whilst the Fenbendazole treatment is implemented. It is also vitally important to stop the rabbit/s re-infecting themselves during the treatment. Routine cleaning of the rabbit’s accommodation with a cleaning disinfectant such as Anigene (previously Trigene) or Vanodine which claim to be effective against E. cuniculi is strongly advised. The dilution rates and cleaning protocol should be followed carefully to ensure safety and effective disinfectant. Human health risks As aforementioned E. cuniculi is a zoonosis. However, it is only worth noting the risks for those individuals who are immunocompromised. For example, there are reports of people with AIDS suffering from E. cuniculi infection. People with normal immune systems don't need to worry. Should rabbits be routinely ‘wormed’? Opinions differ on this. Some individuals believe that treating rabbits every 3 months for 9 days dampens down a possible infection. Others argue that these rabbits may not even have the parasite, may never get any clinical signs or that after the 9 day course has finished they are no more protected than before the treatment course. This is something that all practices will have a protocol on. However there are times when the use of 9 day courses might be helpful:

To reduce the risk of infection at that specific time, such as, around introductions for short periods of time e.g. for a mating

When bonding rabbits it is suggested to treat all rabbits involved in the bond with the longer 28 day course of Fenbendazole either before or during the bond. As aforementioned it is possible to also blood test first and only treat those rabbits that test positive, but if cost is an issue then it is to treat prophylactically on the assumption that either or both rabbits may be infected.

Arthritis What is arthritis? Arthritis, or to give it its proper name, Osteoarthritis, is the general term given to the inflammation of joints. Arthritis can affect any joint within the body. What causes arthritis? Arthritis can occur naturally as rabbits age. General wear and tear on joints over the course of time, especially if the joints are put under extra strain (i.e. large breeds of rabbit, fat/obese rabbits or those with missing limbs), will exacerbate over time and cause the joints to wear quicker than they would under normal circumstances. Another cause of arthritis may include injury to the joint earlier in life. Clinical symptoms Commonly owners report that their rabbit seems to be slowing down or isn’t as active as they used to be. This can be a normal sign of aging, and may creep up very slowly, making recognising and diagnosing arthritis quite difficult on clinical signs alone. Owners may also see their rabbit struggling to move around, they may develop an abnormal gait, have difficulty in washing themselves; so develop a mucky bottom or urine scalding of the perineum.

Diagnosis Arthritis is diagnosed with radiographs. Arthritic joints will show a ‘haze’ or fuzziness around the joint, which is diagnostic of the condition. Treatment It is possible to treat arthritis in order to try and ease some of the discomfort and difficulties that the rabbit may be experiencing. Non-steroidal-anti-inflammatory drugs (NSAIDS), such as oral Meloxicam are commonly used in rabbits to reduce inflammation around the joint/s and to ease the discomfort that is usually present with the condition. Normally these medications will need to be given for the rest of the rabbits life. Cartrophen injections are also used to help treat the condition and can be used to reduce the dose of NSAID’s needed.

Cheyletiella The most common mite seen on rabbits is Cheyletiella, often termed as ‘walking dandruff’ since the mites are visible to the naked eye and if watched closely enough they can be seen to move. This is a zoonotic mite and can therefore in certain circumstances, be passed onto humans. It is believed that most rabbits naturally and sub-clinically carry some Cheyletiella and their immune system keeps the population in check. When this is unbalanced by any other illness or stress, the Cheyletiella multiple and clinical symptoms are seen. Therefore there is often an underlying reason for an outbreak of Cheyletiella which may need further investigation. Clinical signs The common signs to look out for are flaky bald patches of skin, often down the spine and around the rump of the rabbit. The infestation is intensely itchy for the rabbit and they may appear to be constantly scratching or trying to rub the area on something. Treatment Injections of Ivermectin at 7-10 day intervals for 3 – 5 weeks, depending upon the severity of the infestation, are needed to clear up the problem. Alternatively topical Ivermectin can also be applied to the base of the rabbits neck and repeated at specified intervals. Cleaning of the rabbit’s environment, consisting of removing and changing all substrate, washing bedding etc., is also recommended after each Ivermectin injection.

Abscesses An abscess is a walled-off pocket of infection, which contains infecting bacteria, in order to stop them spreading throughout the body - a potentially lethal situation. They are fairly common in pet rabbits and can occur anywhere in the body. Common sites include the skin (after injury, bite wound or surgery) or in the head and neck, frequently secondary to dental or nasolacrimal duct disease. How are abscesses treated? Treatment will vary depending on the site and underlying cause of the abscess, but there are certain basic principles which apply to them all.

The basics Sedation or general anaesthesia is required to remove small and simple abscesses. Lancing, draining and flushing rarely works as rabbit pus is so thick and solid due to a missing enzyme. Many vets also give antibiotics to destroy any bacteria that manage to escape into the body. If the abscess is too large then antibiotics can also be placed inside the abscess cavity to kill off any residual bugs from the abscess as well new ones trying to get in from the outside. Many antibiotics have difficulty gaining access to the bugs in the abscess cavity itself which is why the recurrence rate is high if the capsule isn’t completely removed. Rabbit Pus Rabbit pus is semi-solid. The most common bacteria involved in rabbit abscesses is Pasteurella multiocida and Staphylococcus aureus. The only way to be certain what bacteria are causing an abscess is to take a swab and send it to a laboratory to perform a "culture & sensitivity" test (C&S). The sample should be taken from the abscess wall to try and get some live bacteria, since those in the pus are usually already dead. Nursing care Some rabbits don't seem too bothered by their abscesses and carry on life as normal during treatment, but some need careful nursing and supportive care. One specific point is that clean, soft bedding is essential to reduce the potential for contamination of the wound. "Vet bed" is comfortable and is easy to launder. Hay must still always be available to eat but should be kept well away from any wounds. Analgesia should always be given, since rabbits show very subtle signs of pain and discomfort, which can often be overlooked. Prokinetic medication with syringe feeding and intravenous fluids will be necessary if the rabbit isn’t eating and drinking. Abscess treatments - old and new Over recent years, new treatments have been developed and old ones rediscovered in the fight against abscesses. Ultimately the best treatment is complete surgical excision, but often, due to the location or size of an abscess, this may not be possible. In these cases one or a combination of the following treatments may be implemented. Gels (e.g. Intrasite) help to stimulate normal tissue growth and repair at the edges and base of wounds. Some preparations also inhibit bacterial growth and some newer preparations actually contain antibiotic as a paste and can be used to pack the cavity and left for longer. Antibiotic solutions can be soaked into gauze used to pack abscess cavities, but still need to be changed daily. This method - applying relatively high concentrations of antibiotic directly to the wound - allows the use of antibiotics which would be toxic if given systemically. Care still has to be taken, though, because the drug may be absorbed into the body via the wound which can upset the normal gut function of the rabbit, which is dependent on friendly bugs which may be killed off by the antibiotics. Manuka honey – Honey has antibacterial properties and has been used to treat infected wounds in humans for centuries. Honey promotes the formation of clean, healthy granulation tissue, and acidifies the wound, promoting healing. Prior to commencing treatment with honey, the abscess will require surgical drainage and cleaning and removal of all the necrotic tissue and pus. Twice daily application (which owners can be shown to do), using a syringe to introduce the honey into the cavity is normally recommended. Treatment can be continued for weeks and it doesn’t matter if the rabbit licks at the honey.

Antibiotic beads - Some abscesses are too deep and painful to clean every day, or are inaccessible. Antibiotic impregnated polymethylmethacrylate (PMMA) beads can be packed into the abscess cavity which is then sewn shut. Normally the antibiotic of choice is gentamicin, since others do not work well with the beads and some may cause antibiotic associated diarrhoea if ingested by the rabbit. The beads are left there for anything up to a few months and provide a slow but continuous release of antibiotic as well as filling in the hole left by the abscess and preventing it being filled by newly formed pus. Dextrose: An ancient treatment coming back into fashion is very strong dextrose (sugar) solution. Normally, bacterial growth in the body increases as sugar concentrations rise, because bugs use sugar as a food source. This is why diabetic animals get more infections. However, a 50% dextrose solution is so concentrated that it not only inhibits the growth of most bacteria, but actually kills them by sucking the water out of them so that they die of dehydration. The dextrose can also help draw out fluid that would otherwise accumulate in the cavity. Dextrose solution is soaked onto gauze and packed into the wound, filling the cavity. The dressing must be changed at least once a day - otherwise fluid coming out of the wound will dilute the dextrose, and the dextrose may start to be absorbed into the body, negating its beneficial effects. Calcium hydroxide has been used for many years treating facial abscesses in rabbits, with some success. The solution is syringed into the cleaned out abscess cavity and removed after a week or so. The main problem with calcium hydroxide is its effects on soft tissue. It causes tissue necrosis and nerves, blood vessels and muscles can be very seriously affected. For this reason many vets now steer clear of the treatment, but potentially it may still have its place in the treatment options of rabbit abscesses. Hyaluronidase may help to break up pus and make it easier to remove. N-acetylcysteine (Parvolex), also helps break up pus and mucus, as well as stimulating some immune functions and inhibiting certain aspects of bacterial activity. It can be very effective, but smells rather unpleasant! Location and outcome The site and size of the abscess often determine how difficult the abscess will be to eradicate. Abscesses on the foot or abdomen - subject to the pressure of being walked or laid upon - will take much longer to heal. Confining the rabbit to a cage or small, clean area of flooring might help. Dental abscesses are another particular problem. They may be the first obvious sign of teeth problems, and the severity of the underlying dental disease often dictates the eventual outcome. Any abscess in the head or neck area should ideally prompt a thorough search for dental disease including skull X-rays to determine if the abscess has started to erode bone or cause osteomyelitis (bone infection). Osteomyelitis is associated with a much poorer prognosis and requires aggressive treatment to have any hope of long-term success; complete cure is not common but control of spread with treatment may be possible. Having said this, not all head or neck abscesses are due to dental disease. Sharp grass seeds or strands of hay have been known to penetrate the skin and cause abscesses. Despite all efforts, some rabbits do not survive their abscess problems. They may be unresponsive or impossible to treat successfully. Treatment failure is quite common and often unavoidable due to the underlying cause; the size and site of the abscess; the infecting organism; and the general state of health of the rabbit.