Rabbit Health

Like all pets Rabbits can get ill. The most common symptom that is presented in a veterinary clinic is due to heat stroke.

Heat stroke
If the temperature reaches above 25 degrees Celsius, then you need to take action to prevent your rabbit suffering heat exhaustion Though this is a legitimate concern for all rabbits, rabbits with thick or long coats of hair, overweight, and young or old are at an even greater risk. Temperature, humidity and air ventilation are all factors that contribute to heatstroke in a rabbit. Like people, rabbits are individuals and could respond to these conditions somewhat differently. It is important to check your rabbit consistently to insure they are comfortable and do not overheat. Early detection of heatstroke and proper corrective steps could mean the difference between life and death for your beloved companion.

Signs to look out for:

  • Fast, shallow breathing
  • Hot ears
  • Listlessness
  • Wetness around the nose area
  • Tossing back of head while breathing rapidly from open mouth.

If your rabbit shows signs of heatstroke?
You need to move your rabbit immediately in to a cool place away from any sun. Dampen the ears with cool (not cold) water as this will help to bring down his/her body temperature. Rabbit’s ears are his/her air conditioner. Give your bunny plenty of fresh, cold water with a few ice cubes in it. Another way is what we do here at Melbourne Pet Minders and that is fill up empty plastic coke bottles with water and freeze them, cover them in a cotton cloth and place near the rabbit.

Teeth
Dental disease has several causes, namely genetics, inappropriate diet, injury to the jaw, infection, or cancer.

Malocclusion: Rabbit teeth are open-rooted and continue to grow throughout their lives. In some rabbits, the teeth are not properly aligned, a condition called malocclusion. Because of the misaligned nature of the rabbit’s teeth, there is no normal wear to control the length to which the teeth grow. There are three main causes of malocclusion, most commonly genetic predisposition, injury, or bacterial infection. In the case of congenital malocclusion, treatment usually involves veterinary visits in which the teeth are treated with a dental burr (a procedure called crown reduction or, more commonly, teeth clipping) or, in some cases, permanently removed.

Molar spurs: These are spurs that can dig into the rabbit’s tongue and/or cheek causing pain. These can be filed down by an experienced veterinarian with a dental burr.
Signs of dental difficulty include difficulty eating, weight loss and small stools, anorexia, and visibly overgrown teeth. However, there are many other causes of ptyalism, including pain due to other causes. A visit to an experienced rabbit veterinarian is strongly recommended in the case of a wet chin, or excessive grooming of the mouth area.

Worms
Some vets now recommend worming all rabbits against the parasite Encephalitozoon Cuniculi. Some studies have indicated that over 50% of rabbits may be infected with this parasite. Fenbendazole is used as a deworming agent in other species of animal and has shown to be effective in treating rabbits. In the UK it is now sold in paste form as a treatment for rabbits under the brand name Panacur. It is particularly recommended for rabbits kept in colonies and before mixing new rabbits with each other

Gastrointestinal Stasis

Gastrointestinal stasis is a serious and potentially fatal condition that occurs in some rabbits in which gut motility is severely reduced and possibly completely stopped. When untreated or improperly treated, GI stasis can be fatal in as little as 24 hours.

GI stasis is the condition of food not moving through the gut as quickly as normal. The gut contents may dehydrate and compact into a hard, immobile mass (impacted gut), blocking the digestive tract of the rabbit. Food in an immobile gut may also ferment, causing significant gas buildup and resultant gas pain for the rabbit.

The first noticeable symptom of GI stasis may be that the rabbit suddenly stops eating. Treatment frequently includes subcutaneous fluid therapy (rehydration through injection of saline solution under the skin), drugs for treatment of the buildup of gas in the digestive tract, massage to promote gas expulsion and comfort, possible drugs to promote gut motility, and careful monitoring of all inputs and outputs. The rabbit’s diet may also be changed as part of treatment.

Some rabbits are more prone to GI stasis than others. The causes of GI stasis are not completely understood, but common contributing factors are thought to include:

a lack of fibre in the diet. Many pet rabbits do not get sufficient fresh grass hay, but are instead mistakenly fed only commercial alfalfa pellets originally developed for rapidly increasing mass in rabbits bred for meat.
insufficient moisture in the diet. Fresh, leafy greens are a critical part of a rabbit’s diet in part because of their moisture content, which helps prevent the gut contents from becoming impacted.
lack of exercise. Rabbits confined to a cage frequently do not get the opportunity (or motivation) to run, jump, and play, which is critical in maintaining gut motility.
In addition, GI stasis can be caused by the rabbit not eating for other reasons, such as stress, dental problems, or other unrelated health problems.

GI stasis is sometimes misdiagnosed as cat-like “hair balls” by veterinarians not familiar with rabbit physiology. However, unlike cats, rabbits do not have the ability to vomit.

Upper Respiratory/Snuffles

An over-diagnosed ailment amongst rabbits is respiratory infection. Pasteurella bacteria, known colloquially as “snuffles,” is usually misdiagnosed and has been known to be a factor in the overuse of antibiotics among rabbits.

A runny nose, for instance, can have several causes, among those being high temperature or humidity, extreme stress, environmental pollution (like perfume or incense), or a sinus infection. Options for treating this is removing the pollutant, lowering or raising the temperature accordingly, and medical treatment for sinus infections.

“Runny eyes” can be caused by dental disease or a blockage of the tear duct. Environmental pollution, corneal disease, entropion, distichiasis, or inflammation of the eyes are also causes. This is easy to diagnose as well as treat.

Sneezing can be a sign of environmental pollution (such as too much dust) or food allergy.

While Pasteurella is a bacterium that lives in a rabbit’s respiratory tract, it can flourish out of control in some cases. In the rare event that happens, antibiotic treatment is necessary.
Mites
Cheyletiellosis (also known as “Cheyletiella dermatitis”) is a mild dermatitis caused by mites of the genus Cheyletiella. It is also known as walking dandruff due to skin scales being carried by the mites. Cheyletiella live on the skin surface of dogs, cats, rabbits, and humans. The adult mites are about 0.385 millimeters long, have eight legs that have combs instead of claws, and have palpi that end in prominent hooks. They do not burrow into the skin but live in the keratin level. Their entire 21 day life cycle is on one host. They cannot survive off the host for more than 10 days.Cheyletiellosis is seen more commonly in areas where fleas are less prevalent, because of the decreased use of flea products that are also efficacious for the treatment of this mite.

Cheyletiellosis is highly contagious. Transmission is by direct contact with an affected animal. Symptoms in animals vary from no signs to intense itching, scales on the skin, and hair loss. The lesions are usually on the dorsum of the animal. Symptoms in humans include multiple red, itchy bumps on the arms, trunk, and buttocks. Because humans are an irregular host for the mite, the symptoms usually go away in about three weeks.

Diagnosis is by finding the mites or eggs microscopically in a skin scraping, combing, or on acetate tape applied to the skin. The most common treatment in animals is weekly use of some form of topical pesticide appropriate for the affected animal, often an anti-flea product. Fipronil works well, especially in cats. In unresponsive cases, ivermectin is used, Selamectin is also recommended for treatment. None of these products are approved for treatment of cheyletiellosis.Other pets in the same household should also be treated, and the house or kennel must be treated with an environmental flea spray.

Fly Strike

Fly strike mostly affects rabbits kept in unsanitary conditions and is more likely to occur during summer months. Fly strike happens when flies lay their eggs in the damp or soiled fur of a rabbit. Within 12 hours, the eggs hatch into the larvae stage of the fly, known as maggots. It is often a secondary condition to an open wound, extreme faeces accumulation on the fur of rabbits due to unsanitary living conditions, prolonged contact with water or other environmental favourable to fly larvae. The maggots, initially small and almost invisible to the naked eye, can burrow into the skin of the rabbit and feed on the animals tissue. Within 3–4 days, the larvae can be large as 15 mm long. In rare cases, if not treated, the rabbit can pass into shock and die. Rabbits most susceptible are rabbits living in unsanitary housing, older rabbits who do not move much, and those who are unable to clean their bottom areas carefully. Rabbits raised on solid floors are more susceptible than rabbits raised on wire floors. Rabbits exhibiting one or more episodes of diarrhea are often inspected, especially during the summer months. Fly strike deaths are quick and extremely painful to the rabbit, as hundreds of larvae literally eat it alive

Immunization

Rabbit Calicivirus Disease. CYLAP® HVD vaccine was made available in Australia under permit by the National Registration Authority in November 1995. One dose will provide protection against RCD for twelve months in rabbits older than 10 weeks of age. Only 1 dose is necessary at 10-12 weeks of age.
An earlier vaccination can also be given in some circumstances if earlier protection is warranted.

 

Viral Haemorrhagic Disease

Viral Haemorrhagic Disease (VHD) of rabbits is an acute and usually fatal disease which causes acute necrotic hepatitis (liver disease) in rabbits over 2 months of age. It is caused by a Calicivirus and is similar to European Brown Hare Syndrome which has been present in Europe since 1980.

VHD is a very contagious disease which can be spread directly between rabbits but can also be carried by birds, flies and other insects. Infection occurs via the oral, nasal and conjunctival routes. Unfortunately the virus is very stable in the environment and can survive for up to 105 days at normal room temperature. Once a rabbit is infected with VHD the disease is usually incubated for about 1-3 days. Once the rabbit becomes sick and has a fever, death usually follows in 12- 36 hours.

Signs of VHD in rabbits include elevated rectal temperature (>41 degrees centigrade), lethargy, loss of appetite, convulsions, collapse, vocalization, in-coordination, difficulty breathing and a bloody discharge from the nose. Because the disease quickly causes death few of these signs may be noticed. In 5 to 10% of rabbits the disease takes a more chronic course and here the signs include jaundice, lethargy and weight loss. Rabbits with the chronic form of the disease often die from liver failure within 1 to 2 weeks.

If VHD is suspected there are tests which can be undertaken at Veterinary Laboratories to confirm this, ( other diseases of rabbits may cause similar signs). The most reliable test is electron microscopy of frozen liver samples to search for the viral particles. Testing for antibodies is perhaps unreliable due to an apparent strain of VHD which causes antibody production without causing the disease. Post mortem examination of rabbits which have died from VHD will reveal haemorrhages throughout the liver and other internal organs.

Is it Zoonotic?
Scientists in Australia and New Zealand have found antibodies to the virus present in people who handled rabbits infected with VHD and in 11 species of animals in those countries. The presence of antibodies is generally a reaction to infection. However, no instances of illness or death due to VHD in humans or animals other than rabbits have been reported.

Vaccine
This disease can be prevented by vaccinating your rabbit against VHD using a vaccine called Cylap. This vaccine is a killed vaccine and is very effective. Rabbits may be vaccinated using Cylap from 14 weeks of age and they need to have a booster vaccination every year.

Myxomatosis
Myxomatosis (sometimes shortened to “myxi” or “myxo”) is a disease which affects rabbits. It is caused by the Myxoma virus. First observed in Uruguay in the late 1800s, it was deliberately introduced into Australia in 1950 in an attempt to control rabbit infestation and population there; see rabbits in Australia. It was introduced illegally to France in 1952 and as a result spread to the rest of Europe.

Effects of the disease
In rabbits of the genus Sylvilagus (cottontail rabbits), myxomatosis only causes localized skin tumors, but the European rabbit (Oryctolagus cuniculus) is more severely affected. It is crucial to prevent the misdiagnosis of myxomatosis with Pasteurellosis. Pasteurellosis is a bacterial infection which can be treated with antibiotics. Rabbits treated for Pasteurellosis must often be treated with antibiotics for several weeks to several months. Some rabbits may require surgical intervention in order to remove purulent tissues and abscess. Once Pasteurellosis has become well entrenched, however, there is no guarantee the animal will survive. By contrast, at this writing, there is no treatment for rabbits suffering Myxomatosis, other than palliative care to ease the suffering of individual animals, and the treatment for secondary and opportunistic infections, in the hopes the treated animal will survive. Though the vectors of communication are similar, either contact with an infected animal, cage, feeding or water dishes, and insects, it should be noted, also, that Pasteurellosis can also be spread through breeding, specifically infecting the sexual organs of the animal. Likewise, it is advisable to arrive at the correct diagnosis for the benefit of both rabbit and owner. In cases of Myxomatosis and rabbit hemorrhagic disease (RHD) the owner is often urged to euthanize the animal to ease its suffering. Often the difference between diagnosing a fatal viral infection and a complex, but treatable bacterial infection, like Pasteurellosis, will likely include medications, X-rays, surgery, convalescent and, follow-up care. While surgery and antibiotics may successfully treat Pasteurellosis, they will not treat Myxomatosis or RHD. The owner and attending veterinarian must quickly discern between untreatable diseases and treatable conditions. Myxomatosis and RHD are highly communicable, and untreatable at any stage, whereas rabbits suffering from diseases/conditions other than Myxomatosis and RHD, such as poisoning, heat exhaustion, E. coli or Clostridium perfringens type E enterotoxemia can benefit from timely veterinary intervention.

Myxomatosis: At first, normally the disease is visible by lumps (myxomata) and puffiness around the head and genitals. It then may progress to acute conjunctivitis and possibly blindness; however, this also may be the first indication of the disease. The rabbits become listless, lose appetite, and develop a fever. Secondary bacterial infections occur in most cases which cause pneumonia and purulent inflammation of the lungs. In typical cases where the rabbit has no resistance death may take place with frightening rapidity, often in as little as 48 hrs. Death takes an average of 14 days.

Spread of the disease
After its discovery in 1896 in imported rabbits in Uruguay, a relatively harmless strain spread quickly throughout the wild populations in South America.

In Australia, the virus was first field-tested for population control in 1938. A full-scale release was performed in 1950. It was devastatingly effective, reducing the estimated rabbit population from 600 million to 100 million in two years. However, the rabbits remaining alive were those least affected by the disease. Genetic resistance to myxomatosis was observed soon after the first release and most rabbits acquired partial immunity in the first two decades. Resistance has been increasing slowly since the 1970s, and the disease now only kills about 50% of infected rabbits. In an attempt to increase that number, a second virus (rabbit calicivirus) was introduced into the rabbit population in 1996.

Myxomatosis was unintentionally introduced to France by the bacteriologist Dr. Paul Armand Delille, following his use of the virus to rid his private estate of rabbits in June 1952 (controversially, he inoculated two of the rabbits on his land). Within four months the virus had spread 50 km; Armand suspected this was due to poachers taking infected rabbits from his estate. By 1954, 90% of the wild rabbits in France were dead. The disease spread throughout Europe. It reached the UK in 1953, apparently without human action. Some in the UK deliberately spread the disease, placing sick rabbits in burrows, while many others deplored the cruelty and suffering. The government refused to legislate to make deliberate spread of the disease illegal. By 1955, about 95% of rabbits in the UK were dead.

Myxomatosis is spread by direct contact with an affected animal or by being bitten by fleas or mosquitoes that have fed on an infected rabbit. The myxomatosis virus does not replicate in these insect hosts, but can be physically carried by an insect’s mouthparts, i.e. from an infected rabbit to another susceptible animal. Due to the potential of insect vector transmission, pet rabbits may be susceptible in enzootic areas and vaccination is highly recommended

Use of vaccine
A vaccine is available for pet rabbits (ATCvet code: QI08AD02) but is illegal in Australia due to fears that the immunity conferred by the vaccine could be transmitted through the wild rabbit population, since the vaccine uses a live virus, the Shope fibroma virus.

Natural resistance
The development of resistance to the disease seems to have taken different courses. In Australia, the virus initially killed rabbits very quickly, about 4 days after infection. This gave little time for the infection to spread. However, a less virulent form of the virus has become prevalent there, spreading more effectively by being less lethal. In Europe, rabbits that are genetically resistant to the original virus that was spread. The survival rate of diseased rabbits has now increased to 35% when in the 1950s it was zero. It is conjectured that this is because the main transmission vector in Australia is the mosquito, while in Europe it is the rabbit flea.