Rabbits fed a suitable diet and kept in a healthy environment can live as long as 10 to 12 years. The most common diseases of rabbits include digestive system problems, respiratory infections, and skin disorders. These and other medical problems are discussed in this section. Some of these diseases can also be passed from rabbits to people (see Rabbits: Diseases that can be Spread from Rabbits to People).
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|Diseases that can be Spread from Rabbits to People
Trichophyton mentagrophytes and Microsporum canis
Cheyletiella, Sarcoptes scabei, and Notoedres cati
Digestive disorders in rabbits include both noninfectious (for example, hairballs) and infectious diseases. Intestinal infections are common problems and lead to diarrhea, which can quickly cause serious complications. If you notice that your rabbit has stopped eating or has other signs of a digestive problem, see your veterinarian promptly.
Hair Chewing and Hairballs
Rabbits groom themselves almost constantly, so their stomachs often contain hair. The hair is normally passed through the digestive tract and out through the animal's droppings. Hair chewing is usually caused by a low-fiber diet and can be corrected by increasing the fiber in the diet or feeding hay along with the pellets. Adding magnesium oxide to the diet at 0.25% also may be helpful. In some cases, hair chewing is a result of boredom. Providing toys and items on which to gnaw often stops this abnormal behavior.
The hair becomes a problem only if too much is consumed or if it builds up in the stomach and causes a blockage (commonly called a hairball). If this happens, the rabbit loses its appetite, loses weight, and dies within 3 to 4 weeks. Diagnosing the blockage before the rabbit dies can be difficult, because hairballs may be difficult to feel during a physical examination and they are rarely visible on x-rays. Providing adequate fiber in the diet is critical to maintaining good movement throughout the gastrointestinal tract and to preventing a slowdown or stop of the digestive process in the stomach. This is the most important hairball preventive treatment.
Once a blockage has occurred, the goals of treatment are to remove the obstruction, restore the digestive tract's delicate balance, get the digestive system working properly again, and relieve dehydration and loss of appetite. Treatment includes giving medications to stimulate the digestive system into working again, fluid treatment, pain medication, and anti-ulcer treatment. Reestablishing the natural balance of microorganisms in the animal's digestive system may be assisted by certain medications called probiotics or by having the rabbit eat the soft animal droppings that contain beneficial bacteria from healthy rabbits.
Several remedies have been proposed to assist in the break up or passage of a hairball. Pineapple juice contains the digestive enzyme bromelain and has been used to treat early cases of hairballs; an adult rabbit is given fresh or frozen juice directly into the stomach once or twice a day for 3 days. Both the fluid and the enzyme help to restore normal stomach function and to pass the hairball. Canned pineapple juice is not as effective because the canning process destroys the enzyme. Papaya contains the enzyme papain, also called papayazyme. Papain enzymes do not break down the hair itself, but may help break down the mucus that holds the hairball together. Human health food or nutrition stores carry bromelain and papayazyme supplements as aids to digestion. However, you should check with your veterinarian and always follow his or her recommendations for use of these supplements. Mineral oil, cat hairball treatments, and laxatives are not effective in removing the hair mass. Roughage (hay or straw) should be fed during the treatment to help carry the hair fibers through the digestive tract and out with the animal droppings. Surgical treatment is effective but may be risky.
Prevention is the best option. Providing a high fiber diet, avoiding stress and obesity, adding toys and items for chewing to the cage, and daily combing to remove loose hair effectively prevent this condition.
Intestinal disease is a major cause of death in young rabbits. Although most diarrheal diseases were once lumped together, specific diseases are now being described in more detail. Diet, antibiotic treatment, and other factors create disturbances of the naturally occurring bacteria and may make rabbits more susceptible to intestinal disease.
Diarrhea in your rabbit for any length of time is a cause for concern. If it occurs, you should promptly take your rabbit in for an examination.
Enterotoxemia causes rapidly developing, severe diarrhea, primarily in rabbits 4 to 8 weeks old. It occasionally affects adults and adolescent rabbits. Signs include lack of energy, rough coat, staining around the hind end, and death within 48 hours. Often a rabbit may look healthy in the evening and be dead the next morning. Clostridium spiroforme bacteria are the usual cause of enterotoxemia. Little is known about how the organism is spread; it is assumed to be an organism that is normally present in low numbers and causes no harm. Diet may be a factor in development of the disease. Enterotoxemia is seen less often when high-fiber diets are fed. When used in rabbits, certain antibiotics—including lincomycin, clindamycin, and erythromycin—seem to cause enterotoxemia and their use should be avoided. Diagnosis depends on history, signs, lesions, and detection of Clostridium bacteria.
Individual treatment for enterotoxemia should include supportive fluid treatment. There is little evidence that antibiotics are helpful. A drug used to treat high cholesterol in humans has been used with promising results, both as a preventive and a treatment. Reducing stress (such as crowding) in young rabbits and unlimited feeding of hay or straw are helpful in prevention. Adding copper sulfate to the diet of young rabbits may help prevent enterotoxemia. Check with your veterinarian regarding this medication.
Tyzzer's disease, caused by Clostridium piliforme bacteria, is characterized by large amounts of watery diarrhea. Other signs of illness are loss of appetite, dehydration, loss of energy, staining of the hindquarters, and death within 1 to 3 days in recently weaned rabbits. In severe outbreaks, more than 90% of affected rabbits may die. Some rabbits may develop long-lasting infections that appear as a wasting disease. The infection is spread when rabbits eat contaminated food or droppings and is associated with poor sanitation and stress. Internally, there is damage to the intestine, liver, and heart. A veterinarian can perform tests to confirm the diagnosis of Tyzzer's disease.
Most antibiotics used to treat this disease in other animals have not been effective in rabbits. However, the antibiotic oxytetracycline has helped in some cases. Following a disease outbreak, thorough disinfection and decontamination of the cage or hutch using either 1% peracetic acid or 3% bleach should be done to reduce the presence of bacteria.
Escherichiacoli bacteria can cause rabbit diarrhea called colibacillosis. Their presence can be confusing, however, as these bacteria often multiply greatly in number when a rabbit develops diarrhea for any reason. Healthy rabbits do not have E. coli associated with their digestive tract.
Two types of colibacillosis are seen in rabbits, depending on their age. Rabbits 1 to 2 weeks old develop a severe yellowish diarrhea that is often fatal. It is common for entire litters to die of this disease. In weaned rabbits 4 to 6 weeks old, diarrhea very similar to that described for enterotoxemia (see Rabbits: Intestinal Diseases) is seen. Death often occurs in 5 to 14 days. Rabbits that survive are not healthy or strong and do not grow to their normal size. A veterinarian is able to make a diagnosis by doing a test to find E. coli. In severe cases, treatment is not successful; in mild cases, antibiotics may be helpful. Your rabbit's cage and other living areas should be thoroughly sanitized. High-fiber diets appear to help prevent the disease in weaned rabbits.
Proliferative enteropathy, caused by Lawsonia intracellularis bacteria, may cause diarrhea in recently weaned rabbits. Signs include diarrhea, depression, and dehydration, which go away within 1 to 2 weeks. This disease does not cause death unless it occurs together with infection by another organism that causes intestinal disease. Isolation of sick animals and treatment of signs is advised.
Mucoid enteritis is a diarrheal disease of rabbits that causes inflammation, an abnormally high level of secretions, and a buildup of mucus in the small and large intestines. While the cause is unknown, it may occur at the same time as other intestinal diseases. Factors that may contribute to the disease include recent dietary changes, too much or too little fiber in the diet, antibiotic treatment, environmental stress, and infection with other bacteria. Signs are gelatinous or mucus-covered droppings, loss of appetite, loss of energy, below normal temperature, dehydration, rough coat, and often a bloated abdomen due to excess water in the stomach. Your veterinarian may be able to feel an intestinal blockage. The hind end is often covered with mucus and signs of diarrhea. Diagnosis is based on signs and findings of gelatinous mucus in the colon after death. There is no effective treatment, but intense fluid therapy, an enema to remove the mucus, antibiotics, and pain relievers may be tried. Rabbits may live for about 1 week. Prevention is the same as for any rabbit intestinal disease.
Rotavirus causes diarrhea in rabbits. It is shed in the droppings of infected rabbits and, therefore, is probably transmitted by the droppings-mouth route. Young rabbits of weaning age are most susceptible. Rotavirus appears to be only mildly disease-causing on its own, but most rotavirus infections are complicated with disease-causing bacteria such as Clostridium or Escherichia coli. The mixed infection results in a much more deadly syndrome. There is no treatment, but the infection appears to be self-limiting if susceptible rabbits are not continually introduced into the population. Stopping breeding for 4 to 6 weeks seems to allow the disease to run its course, because infected does do not infect their offspring.
Rabbit calicivirus disease, also known as viral hemorrhagic disease, is highly infectious in European rabbits (Oryctolagus). Cottontail rabbits and jackrabbits are not susceptible. Humans and other mammals are also not affected. The calicivirus is highly contagious and can be transmitted by direct contact with infected rabbits or indirectly by inanimate objects. Infection results in a severe feverish disease causing liver damage, inflammation of the intestines, and damage to lymph nodes, followed by a condition in which the blood is unable to coagulate and massive ruptures of blood vessels in multiple organs. Rabbits show few signs and die within 24 hours of fever onset. The infection rate in an affected group is often close to 100% and the death rate is 60 to 90%.
Rabbit calicivirus disease was first reported in 1984 in the People's Republic of China. From there, it spread through the domestic and wild rabbit populations in continental Europe. The first report of the virus in the Western hemisphere was in Mexico City in 1988. Recent outbreaks of rabbit calicivirus disease occurred in Australia (1995), New Zealand (1997), and Cuba (1997). Rabbit calicivirus disease was confirmed in a group of 27 rabbits in Iowa in 2000, in the United States. The source of infection was not determined. The outbreak was contained, the virus eliminated, and the US remains disease free. This is a reportable disease, which means that any veterinarian who identifies it must notify the appropriate governmental authorities.
is a common and worldwide disease in rabbits. It is caused by protozoa (single-celled organisms). There are 2 forms of the disease: hepatic, which affects the liver, and intestinal, which affects the intestines. Both types are caused by Eimeria protozoa. Transmission of both the forms is by ingestion, usually in contaminated feed or water. Rabbits that recover frequently become carriers.
Young rabbits are most susceptible to hepatic coccidiosis. Affected rabbits may have no appetite and have a rough coat. Disease is usually mild, but growing rabbits may fail to gain weight. Death occasionally occurs after a short period of illness.
Intestinal coccidiosis can occur in rabbits receiving the best of care, as well as in rabbits raised under unsanitary conditions. Typically, infections are mild and often no signs are seen. Good sanitation programs that can eliminate hepatic coccidiosis do not seem to eliminate intestinal coccidiosis.
Your veterinarian can perform laboratory tests to confirm the diagnosis of coccidiosis. Treatment is difficult, and is aimed at controlling rather than curing the disease. Antibacterial and/or anticoccidial drugs may be prescribed. Rabbits that are treated successfully are immune to subsequent infections. Follow your veterinarian's treatment program carefully for the best results.
Treatment for coccidiosis will not be successful unless a sanitation program is started at the same time. Feed hoppers and water crocks must be cleaned and disinfected daily to prevent them from becoming contaminated with animal droppings. Hutches should be kept dry and the droppings removed often (twice a day is recommended). Wire cage bottoms should be brushed daily with a wire brush to help break the life cycle of the protozoa. Ammonia (10%) solution is the best choice to disinfect cages or other equipment exposed to the droppings.
Although adult tapeworm infections are rare in domestic rabbits, finding tapeworm larvae in rabbits is common. Rabbits serve as the intermediate hosts for 2 species of tapeworms found in dogs. Generally, there are no signs. Treatment is usually not attempted, but control is accomplished by restricting access of dogs (the final host of the tapeworm) to the area in which food and nesting material are stored. Roundworms, such as Baylisascaris procyonis, have been reported in rabbits. Signs may include ear infection or “wry neck.” No effective treatment is available.
The rabbit pinworm usually does not cause disease but often is upsetting to owners. Transmission of the pinworm occurs by ingesting contaminated food or water. The adult worm lives in the large intestine. Diagnosis is made by finding the eggs during examination of the droppings. Single treatments are not very effective because the life cycle is direct and reinfection is common. Several drugs commonly used to treat worms in animals are effective in rabbits. Rabbit pinworms are not transmissible to humans.
Eye and Ear Disorders
Mature bucks and young rabbits are particularly susceptible to bacterial conjunctivitis (weepy eye), however, the incidence is low. Transmission is by direct contact with an infected rabbit or contaminated objects, such as bedding materials. Affected rabbits rub their eyes with their front feet. Eye ointments containing antibiotics, or antibiotics and a steroid, are usually recommended for treatment. Follow your veterinarian's treatment program carefully because many antibiotics are not suitable for use in rabbits. This infection commonly recurs. Flushing the tear duct with an antibiotic solution is often beneficial in chronically affected rabbits.
Bone and Muscle Disorders
Breaking or dislocating the lower back causing compression or severing of the spinal cord is common in rabbits. Common signs include hind end muscle weakness or paralysis and inability to control waste elimination. Initial signs of paralysis may go away within 3 to 5 days as swelling around the cord shrinks. Supportive treatment includes anti-inflammatory steroids to reduce damage from swelling. Paralysis and inability to control waste elimination after 1 to 2 weeks indicates that most likely the rabbit will not return to normal and requires putting the animal to sleep.
Splay leg is generally an inherited disorder, although it can occur after injury to the leg. The signs include abduction (distortion) of one or more legs as early as 3 to 4 weeks of age; an inability to walk or to support weight may also be seen. The right rear limb is most commonly affected. The condition may affect one or both sides of the body. There is no effective treatment.
Lung and Airway Disorders
Pasteurellosis, a bacterial infection caused by Pasteurella multocida, is common in domestic rabbits. It is highly contagious and is transmitted primarily by direct contact, although transmission by coughing or sneezing may also occur. In conventional colonies, 30 to 90% of apparently healthy rabbits may be carriers that show no signs of the disease. Signs of pasteurellosis include rhinitis (stuffy, runny nose), pneumonia (inflammation of one or both lungs), abscesses (pus-filled sores), reproductive tract infections, wry neck or head tilt (torticollis), and blood poisoning.
Rhinitis (snuffles or stuffy, runny nose) is inflammation of the mucous membranes of the air passages and lungs and can be short or long-lasting. Pasteurella bacteria are the usual culprits, but other bacteria may cause it as well. The initial sign is a thin, watery discharge from the nose and eyes. The discharge later becomes pus-filled. The fur on the inside of the front legs just above the paws may be matted and caked with dried discharge or this area may be clean with thinned fur as a result of pawing at the nose. Infected rabbits usually sneeze and cough. In general, rhinitis occurs when the resistance of the rabbit is low. Recovered rabbits are likely carriers.
Pneumonia is common in domestic rabbits. The cause is typically Pasteurella bacteria, but other bacteria may be involved. The infection causes inflammation of the lungs and of the membrane surrounding the lungs, accumulation of fluid in the lungs and chest, and ruptured blood vessels of the sac around the heart. Upper respiratory disease (rhinitis or snuffles, see above) often occurs before pneumonia. Inadequate ventilation, poor sanitation, and dirty nesting material are contributing causes. Affected rabbits lack appetite and energy, and may cough and have difficulty breathing or a fever. Rabbits usually die within 1 week after signs appear. Diagnosis depends on signs, physical changes, and laboratory test results. Antibiotic treatment often fails because the pneumonia is advanced before it is detected.
Reproductive disorders of rabbits include bacterial infections and metabolic disorders. Also, see Rabbits: Breeding and Reproduction of Rabbits.
Pasteurella bacteria often cause genital infections (pasteurellosis), which may also be caused by several other organisms. The typical signs include inflammation of the reproductive tract and are usually seen in adults. Does are more often infected than bucks. If both horns of the uterus are affected, often the doe becomes sterile; if only one horn is involved, a normal litter may develop in the other. The only sign of an infection in the uterus may be a thick, yellowish-gray vaginal discharge. Bucks may discharge pus from the urethra or have an enlarged testicle. Longterm infection of the prostate and seminal vesicles is likely. Because the infection can be passed during breeding, infected animals should not be bred. Surgical removal of the infected reproductive organs along with antibiotic treatment is required for pet rabbits. The contaminated hutch and its equipment should be thoroughly disinfected. Diagnosis of pasteurellosis is based on signs and laboratory tests that detect the bacteria. Nasal swab tests can be performed to identify carriers. Treatment is difficult and may not completely get rid of the organism. Antibiotics seem to provide only temporary remission, and the next stress (such as giving birth to a litter) may cause relapse.
Ketosis (Pregnancy Toxemia)
Ketosis is a rare disorder that may result in death of does 1 to 2 days before giving birth. The disease is more common in first-litter does. Possible contributing factors include obesity and lack of exercise. Signs include loss of appetite, dullness of eyes, sluggishness, difficulty breathing, and lying down. The most significant physical change is fatty deposits in the liver and kidneys (noted after death has occurred). Injection of fluids that contain glucose may correct the disease. Breeding does early, before they become too fat, is also helpful. Hairballs in the stomach often predispose a rabbit to developing ketosis.
Treponematosis (Vent Disease, Rabbit Syphilis)
Treponematosis is a venereal disease of rabbits caused by Treponema bacteria. It occurs in both sexes and is transmitted through sexual intercourse and from the doe to her offspring. Although it is closely related to the organism that causes human syphilis, the bacteria is not transmissible to other domestic animals or humans. The incubation period is 3 to 6 weeks. Small blisters or slow-healing sores are formed, which then become covered with a heavy scab. These sores usually are confined to the genital region, but the lips and eyelids may also be involved. Infected rabbits should not be mated. Diagnosis is based on the signs and laboratory tests to identify the bacteria. Hutch burn (see Rabbits: Hutch Burn (Urine Burn)) is often confused with treponematosis because the diseases have very similar signs.
An injection of penicillin G is necessary to completely get rid of treponematosis. All rabbits in a group must be treated, even if no signs of disease are present. Sores usually heal within 10 to 14 days, and recovered rabbits can be bred without danger of transmitting the infection. A potential side effect of penicillin treatment is diarrhea and the possibility of an intestinal disease outbreak due to the increased levels of bacteria in the gut. Rabbits treated with penicillin should be switched to hay and treated with antidiarrheal medications immediately if needed (see Rabbits: Intestinal Diseases). As with any antibiotic treatment for rabbits, your veterinarian's dosage instructions should be followed carefully and you should monitor the overall health of your pet for any signs of diarrhea or listlessness.
Mastitis (Blue Breasts)
Mastitis (inflammation of the breasts) affects nursing does and may progress to a blood infection that rapidly kills the doe. It is usually caused by staphylococcal bacteria, but other bacteria may be involved. Initially, the mammary glands become hot, reddened, and swollen. Later, they may become a bluish color, hence the common name, “blue bag” or “blue breasts.” The doe will not eat but may crave water. Fever is often present.
If antibiotic treatment is started early (the first day the doe goes off feed), the rabbit may be saved and damage limited to 1 or 2 mammary glands. Because penicillin often causes diarrhea in rabbits, does treated with this antibiotic should be fed hay or some other high-fiber diet rather than a pelleted ration (see Rabbits: Intestinal Diseases). Kits should not be fostered to another doe because they will spread the infection. Handrearing of infected young may be attempted but is difficult.
The frequency of mastitis can be reduced if nest boxes are maintained without rough edges to the entrance, which can traumatize the teats when the doe jumps in and out of the nest box. Other preventive measures include sanitizing the nest box both before and after use.
Skin disorders in rabbits often lead to patches of hair loss (alopecia). Many of these problems are caused by parasites, such as mites, that will require medication from your veterinarian. Regular grooming will allow you to check your rabbit's skin and identify potential problems early.
Hutch Burn (Urine Burn)
Hutch burn is caused by wet and dirty hutch floors. It also occurs in rabbits that constantly dribble urine due to poor bladder control. The area surrounding the anus and genital region becomes inflamed and chapped. This is followed by infection with disease-causing bacteria. Brownish crusts cover the area and a bloody, pus-filled discharge may be present. Keeping hutch floors clean and dry and applying an antibiotic ointment to the sores speeds recovery.
Hutch burn is often confused with a bacterial disease called treponematosis see Rabbits: Treponematosis (Vent Disease, Rabbit Syphilis); only a veterinarian can determine the difference by finding the spirochete bacteria under a microscope.
Wet Dewlap (Moist Dermatitis)
Female rabbits have a heavy fold of skin on the front of the neck called a dewlap. As the rabbit drinks, this skin may become wet and soggy, which leads to inflammation. Possible causes include open water crocks and damp bedding. Dental malocclusion that causes excessive salivation can also be a cause. The hair may fall out, and the area may become infected or infested with fly larvae (maggots). The area often turns green if infected with Pseudomonas bacteria. If the area becomes infected, the hair should be clipped and antiseptic dusting powder applied. In severe cases, antibiotics injected by a veterinarian may be necessary.
Automatic watering systems with drinking valves generally prevent wet dewlaps. If open water receptacles are used, they should have small openings or be elevated.
This condition, sometimes called ulcerative pododermatitis, does not involve the hock (the ankle joint) but the sole of the hindfoot and, less commonly, the front paws. The cause is either pressure on the skin from bearing the body weight on wire-floored cages or trauma to the skin from stamping, with infection of the dead skin. Several factors, including a buildup of urine-soaked droppings, nervousness, hind-end paralysis after a spinal cord injury, and the type of wire used, may influence development of this disease. Genetics are also involved. Heavy-breed rabbits such as the Rex, Flemish Giant, and Checkered Giant are more susceptible. Rabbits with sore hocks sit in a peculiar position with their weight on their front feet; if all 4 feet are affected, they tiptoe when walking.
Various cleansing agents can be used to clean the sores, followed by topical and injected antibiotics. X-rays may be needed to check for inflammation of bone and bone marrow, which may be a complication. The rabbit must be removed from the cage or given a solid floor (board or mat) on which to sit or rest. Treatment is difficult and time consuming, and the condition often comes back. Because big feet and thick footpads are hereditary, selection of breeding stock for these traits has reduced the incidence of sore hocks.
Ringworm is a fungal infection that is common in rabbits. Affected animals develop raised, reddened, circular sores that are capped with white, bran-like, flaky material. The sores generally appear first on the head and then spread to other areas of the skin. Ringworm is generally associated with poor sanitation, poor nutrition, and other environmental stressors. The cause is most commonly the fungus Trichophyton mentagrophytes and occasionally Microsporum canis. Transmission is by direct contact. Objects such as hair brushes, which are often overlooked during disinfection, can play a significant role in spreading infection. Carriers without signs are very common. Your veterinarian can do tests to confirm the diagnosis.
Because infected rabbits can spread the disease to humans and other animals, they should be isolated and treated. Owners of infected rabbits should avoid close contact with their pets and use disposable gloves, followed by thorough hand and arm washing when handling infected rabbits, cleaning cages and equipment, or disposing of waste materials. Antifungal drugs are usually effective in treating ringworm. Antifungal creams applied to the skin also may be effective. You must carefully follow your veterinarian's treatment program to control this infection.
Myxomatosis is a deadly disease of all breeds of domesticated rabbits. It is caused by myxoma virus, a type of poxvirus. Myxomatosis is called “big head” and is characterized by skin sores or myxomas (benign tumors composed of mucus and a gelatinous material embedded in connective tissue). Wild rabbits are quite resistant and usually do not get myxomatosis. All other mammals are resistant to the virus. Myxomatosis has a worldwide distribution. In the US, myxomatosis is restricted largely to the coastal area of California and Oregon. These areas correspond to the geographic distribution of the California brush rabbit, the reservoir of the infection. Transmission is by bites from mosquitoes, fleas, biting flies, and by direct contact.
The first sign is conjunctivitis (inflammation of the eye) that rapidly becomes more noticeable and is accompanied by a milky discharge from the eye. The rabbit has no energy and no appetite, with a fever that may reach 108°F (42°C). In severe outbreaks, some rabbits die within 48 hours after signs appear. Those that survive become progressively weaker and develop a rough coat. The connective tissue of the eyelids, nose, lips, and ears fill with fluids, which gives a swollen appearance to the head. The ears may droop. In females, the vulva becomes inflamed and swollen with fluid; in males, the scrotum swells. Other signs include a pus-filled discharge from the nose, difficulty breathing, and coma leading to death, which usually occurs within 1 to 2 weeks after signs appear. Occasionally, a rabbit survives for several weeks; in these cases, thick lumps appear on the nose, ears, and forefeet.
The seasonal incidence of the disease, signs (especially the swollen genitalia), and high death rate all help veterinarians make the diagnosis.
A vaccine prepared from a myxomatosis virus has protected rabbits from infection, but it is not available in the US. Because there is no effective treatment, euthanasia is suggested. Preventive measures include protecting rabbits from exposure to insects and ticks that transmit diseases.
Shope fibromas, a type of benign tumor, are found under natural conditions only in cottontails, although domestic rabbits can be infected by virus-containing material. Fibromas may be found in domestic rabbits in areas where these tumors occur in wild rabbits and where husbandry practices allow contact with insects and ticks that transmit diseases.
The fibromas are caused by a virus and usually occur on the legs, feet, and ears. The earliest physical sign is a slight thickening of the tissues just below the skin, followed by development of a soft swelling with distinct edges. These tumors may persist for several months before regressing, leaving the rabbit essentially normal.
Two types of infectious benign tumors, known as papillomas, occur infrequently in domestic rabbits. Papillomas in the mouth, caused by the rabbit oral papillomavirus, consist of warts or small, grayish white, lumps attached by a narrow stalk on the bottom of the tongue or on the floor of the mouth. The second type, caused by the cottontail (Shope) papillomavirus, is characterized by horny warts on the neck, shoulders, ears, or abdomen and is primarily a natural disease of cottontail rabbits. Insects and ticks transmit the virus; therefore, insect control could be used as means of disease prevention. The oral papillomavirus is distinct from the Shope papillomavirus (which is also distinct from the Shope fibroma virus). Skin tumors caused by the Shope papillomavirus never occur in the mouth. Neither type of papillomatosis is treated, and the condition usually goes away on its own.
Mites and Fleas
Ear mites are a common parasite in rabbits. Mites irritate the lining of the ear and cause a watery fluid and thick brown crusts to build up, creating an “ear canker.” Infested rabbits scratch at and shake their head and ears. They lose weight and may develop infections, which can damage the inner ear, reach the central nervous system, and result in torticollis or “wry neck” (a twisting of the neck to one side, resulting in the head being tilted). Your veterinarian will remove the brown crumbly discharge and then treat the affected ear with one of the drugs that are approved for use in dogs and cats. Products containing a substance that breaks down the waxy secretions in the ear are particularly useful in removing the heavy, crusted material. The medication should be applied within the ear and down the side of the head and neck. Ear mite infestations are less likely to occur when rabbits are housed in wire cages than in solid cages. The mite is readily transmitted by direct contact.
Fur mites are also common on rabbits. Because these mites live on the surface of the skin and do not burrow into the skin, they do not cause the intense itching seen with sarcoptic mange. Fur mite infestations usually do not cause any signs unless the rabbit becomes weakened due to age, illness, or other stress. The mites may be noticed as “dandruff.” Scraping the dandruff from the skin onto a dark paper or background will demonstrate this and has led to the nickname “walking dandruff” for this condition. Transmission is by direct contact. A diagnosis can be made by looking at skin scrapings under a microscope. Fur mites may cause a mild skin irritation or inflammation in humans. Weekly dusting of animals and bedding with permethrin powder can control these mites.
Rabbits are rarely infested with the mange mites that cause sarcoptic mange (canine scabies) or notoedric mange (feline scabies). These mites burrow into the skin and lay eggs. When infestation does occur, the rabbits are extremely itchy. It is difficult to get rid of these parasites on domestic rabbits. The condition is extremely contagious and can be transmitted to humans.
Fleas can affect rabbits and many other animals. Imidacloprid is a drug that kills adult fleas on contact; products containing this drug have been successfully used to treat rabbits infested with fleas. Products containing fipronil should never be used in rabbits. Ask your veterinarian for a treatment recommendation if your rabbit has fleas.
Kidney and Urinary Tract Disorders
The formation of mineral deposits in the urinary tract (sometimes known as kidney or bladder stones) is common in pet rabbits. The condition is generally suspected when blood is found in the urine. Several factors may contribute to the formation of kidney stones, including nutritional imbalance (especially the calcium:phosphorus ratio), heredity, infection, inadequate water intake, and metabolic disorders. Treatment involves surgically removing the stones, acidifying the urine, and reducing dietary calcium. Because alfalfa is high in calcium and is one of the main dietary components of rabbit pellets, switching the diet to grass or timothy hay and rolled oats may help prevent the condition from returning.
Disorders Affecting Multiple Body Systems
Several infectious diseases and other disorders can affect more than one body system in rabbits. The most common of these are described here.
Abscesses (pus-filled and inflamed sores) on the internal organs and below the skin, caused by Pasteurella bacteria, may not be apparent for long periods and then suddenly rupture. When bucks penned together fight, their wounds often develop abscesses. Your veterinarian will likely drain the abscess and prescribe an appropriate antibiotic. These signs frequently recur.
Rabbits are sensitive to heat. Hot, humid weather, along with poorly ventilated hutches or transport in poorly ventilated vehicles, may cause death, particularly in pregnant does. Affected rabbits stretch out and breathe rapidly. Outdoor hutches should be constructed so that they can be sprinkled in hot, humid weather. Unlimited access to cool water should be provided. When the environment can be controlled, optimal conditions include a temperature of 50 to 70°F (15 to 21°C) and a relative humidity of 40 to 60%, with good ventilation. Wire cages are preferable to solid hutches.
Treatment for heat exhaustion consists of immersing rabbits in cold water during the heat of the day, especially those that will give birth to a litter in the next day or two. Breeding bucks may lose a majority of viable sperm and might not breed successfully for several weeks while new sperm production replaces the sperm killed by heat stress.
Listeriosis, a bacterial infection of the blood characterized by sudden death or abortion, is seen occasionally and is most common in does near the end of pregnancy. Poor husbandry and stress may be important in starting the disease. Signs may include loss of appetite, depression, and weight loss. The bacteria that cause listeriosis, Listeria monocytogenes, spreads by way of the blood to the liver, spleen, and uterus. It can infect many animals, including humans. Because diagnosis is rarely made before death, treatment is seldom attempted. If your pregnant doe becomes listless, loses weight, or seems depressed, you should contact your veterinarian promptly.
Tularemia (infection with Francisella tularensis bacteria) is rare in domestic rabbits, but wild rabbits and rodents are highly susceptible and have been involved in most outbreaks among domesticated rabbits. The bacteria also can infect people, and up to 90% of human cases are linked to wild rabbit exposure. The bacteria is found widely in the south central United States. It is highly infectious and can be passed through the skin, through the respiratory tract by way of aerosols, by ingestion, and by bloodsucking insects and ticks. Tularemia can cause a deadly blood infection. Diagnosis is based on findings made after death occurs, such as signs of bacterial blood infection, small bright white spots on the liver, and enlargement of the liver and spleen. There is no effective treatment for infected rabbits. Tularemia is a reportable disease and your veterinarian is required to tell public health authorities about any cases that occur.
Encephalitozoonosis is a widespread protozoal infection of rabbits and occasionally of mice, guinea pigs, rats, and dogs. It causes pitting and sometimes inflammation of the kidneys; sometimes small masses occur in the brain and kidneys. Usually, no signs are seen. How it is transmitted is not definitely known, but the organism is shed in the urine. It seems to be mildly contagious in a rabbit colony. Your veterinarian can confirm a diagnosis using laboratory tests. Effective treatment has not been established. Prevention requires good sanitation.
Cancers and Tumors
By far, the most common tumor in rabbits is uterine adenocarcinoma (malignant tumor in the uterus). The likelihood of developing this cancer is related to breed. The disease may occur as multiple tumors that often spread to the liver, lungs, and other organs. This cancer is the primary reason for spaying (removing the ovaries and uterus) any nonbreeding female rabbits. Monitoring for the spread of the cancer should follow surgical removal of the uterine tumor. Malignant lymphomas (tumors in the lymph nodes) are relatively common and may occur in rabbits less than 2 years old. Typically, tumors in the lymph nodes cause enlargement of the kidneys, spleen, liver, and lymph nodes.
Papillomas and Shope fibromas are 2 types of benign skin tumors that occur in rabbits (see Rabbits: Shope Fibromas).
Last full review/revision July 2011 by Diane McClure, DVM, PhD, DACLAM