Disorders and Diseases of Rabbits

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). While some rabbits consume excessive amounts of hair that truly obstruct the passage of food through their gastrointestinal (GI) tracts, more often, rabbits that do not eat enough dietary fiber (as hay) or those that stop eating for other reasons (such as dental problems) develop signs that mimic those of a hairball. In rabbits consuming inadequate dietary fiber or when they stop eating altogether, the normal healthy population of bacteria that they have in their GI tracts changes, and gas-producing bacteria take over. Food passage through the intestines slows as gas-producing bacteria overgrow, and the gas makes the rabbit feel even more bloated, uncomfortable, and unlikely to eat. This vicious cycle, referred to as GI stasis, is one of the most common illnesses for which pet rabbits are brought into the veterinary hospital and is often mistaken for a hairball that is truly obstructing the GI tract.

It can be hard to distinguish true hairballs from GI stasis, and veterinarians typically use x-rays, ultrasonography, and CT scans to tell them apart. True hairballs that are blocking the GI tract are life-threatening emergencies that require surgery to remove. GI stasis, on the other hand, is typically not treated with surgery but instead with supportive care, including fluids to decrease dehydration, probiotics to reestablish normal GI bacteria, pain relievers, and syringe feeding to get food moving through the GI tract again. These same treatments are administered to rabbits after hairball removal surgery. Like hairballs, GI stasis can be life-threatening if it is left untreated.

The best way to prevent both hairballs and GI stasis is to provide unlimited amounts of hay, avoid stress and obesity, enrich the environment with toys and safe items to chew, and brush the rabbit to remove loose hair.

Intestinal disease is a major cause of death in young rabbits. Diet, antibiotic treatment, and other factors disturb naturally occurring gut 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. 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. Diet may be a factor in development of the disease. Enterotoxemia is seen less often when high-fiber diets are fed. Certain antibiotics—including lincomycin, clindamycin, and erythromycin—seem to cause enterotoxemia in rabbits and should not be given orally. Diagnosis depends on history, signs, lesions, and detection of Clostridium bacteria.

Treatment for enterotoxemia includes fluid treatment and supportive care. There is little evidence that antibiotics are helpful. Reducing stress (such as crowding) in young rabbits and feeding unlimited hay or straw help prevent the disease. Adding copper sulfate to the diet of young rabbits may also help prevent enterotoxemia. Check with your veterinarian regarding this medication.

Tyzzer 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. The disease causes damage to the intestines, liver, and heart. A veterinarian can perform tests to confirm the diagnosis of Tyzzer 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 helps reduce the presence of bacteria.

Escherichia coli bacteria can also cause diarrhea in rabbits; this disease is called colibacillosis. These bacteria also tend to multiply when a rabbit develops diarrhea for any reason. Healthy rabbits do not have E coli in their digestive tracts.

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 above) is seen. Death often occurs in 5 to 14 days. Rabbits that survive are not healthy and may not grow to their normal size. A veterinarian makes the diagnosis by testing for 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 along with infection by another organism that causes intestinal disease. Isolation of sick animals and treatment of symptoms is advised.

Mucoid enteritis is a diarrheal disease of rabbits that causes intestinal inflammation, excessive production of mucus in the small and large intestines, and the passage of diarrhea covered in mucus. The cause is unknown, and this condition may occur at the same time as other intestinal diseases. Factors that 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, low body 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 intensive fluid therapy, antibiotics, and pain relievers may be tried. Affected rabbits may live for about 1 week. Prevention is the same as for any other rabbit intestinal disease.

Rotavirus causes diarrhea in rabbits. It is shed in the droppings of infected rabbits and is probably transmitted by the droppings-mouth route. Young rabbits of weaning age are most susceptible. Rotavirus appears to cause only mild disease on its own, but most rotavirus infections are complicated with disease-causing bacteria such as Clostridium or E 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 affected does do not infect their offspring.

Rabbit calicivirus disease, also known as rabbit hemorrhagic disease virus (or RHDV2), is a highly infectious, contagious virus first seen in wild European rabbits. Initially, this disease was not seen in wild rabbits in the US or in domestic rabbits, but it has been documented in both these populations in states across the US since 2020. 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 fever and causes liver damage, inflammation of the intestines, and damage to lymph nodes, followed by a disorder of blood clotting and bleeding within 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 China. From there, it spread through domestic and wild rabbit populations in continental Europe. The first report of the virus in the Western Hemisphere was in Mexico City in 1988. 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. The source of infection was not determined. This is a reportable disease, which means that any veterinarian who identifies it must notify the appropriate government authorities. The only ways to prevent this serious disease is to limit contact with other rabbits and to administer the initial, 2-shot vaccination series against RHDV2, followed by annual booster shots.

Coccidiosis is a common disease in rabbits across the world. 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 forms is by ingestion, usually in contaminated feed or water. Rabbits that recover frequently become carriers.

Young rabbits are the age group 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 regardless of the conditions in which rabbits are housed. Infections are typically 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. Anticoccidial drugs may be prescribed. Rabbits that are treated successfully for hepatic coccidiosis are immune to subsequent infections. Follow your veterinarian’s treatment program carefully for the best results.

Treatment for hepatic 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 feces removed often. Wire cage bottoms should be brushed daily with a wire brush to help break the life cycle of the protozoa. Ammonia solution (10%) can be used to disinfect cages or other equipment exposed to contaminated feces.

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 of infection. Treatment is usually not attempted, but control is accomplished by keeping dogs (the final hosts of the tapeworm) away from the area in which food and nesting material are stored.

The roundworm Baylisascaris procyonis has been reported in rabbits. Infection may cause signs of nervous system disease, such as loss of balance, tremors, and head tilt. No effective treatment is available.

The rabbit pinworm usually does not cause disease but may be 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 feces. Effective treatments are available. Rabbit pinworms cannot be transmitted to humans.

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. Hairballs in the stomach may also be a factor. Signs of ketosis include loss of appetite, dullness of eyes, sluggishness, and difficulty breathing. To treat ketosis, your veterinarian may inject fluids that contain glucose.

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 the species of Treponema that causes rabbit treponematosis is closely related to the species that causes human syphilis, these bacteria are not transmissible to other domestic animals or humans. The incubation period is 3 to 6 weeks. Affected rabbits develop small blisters or slow-healing sores that 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 bred. Diagnosis is based on the signs and laboratory tests. Hutch burn (see below) is often confused with treponematosis because the diseases have very similar signs.

Treponematosis is treated with penicillin injections. Rabbits should not be given penicillin by mouth because oral penicillin can cause dangerous antibiotic-associated diarrhea. 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.

Mastitis (inflammation of the breasts) affects nursing does and may cause fatal blood infection. It rarely occurs in pet rabbits. Mastitis is usually caused by Staphylococcus 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 names “blue bag” and “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 stops eating), the rabbit may be saved and damage limited to 1 or 2 mammary glands. Although injectable penicillin is typically safe for rabbits, whereas oral penicillin is not, even injectable penicillin may cause diarrhea in rabbits; therefore, does treated with this antibiotic should be fed additional hay, rather than pellets ( see Intestinal Diseases), to try to maintain a healthy population of intestinal bacteria. Kits (newborn rabbits) should not be fostered to another doe because they will spread the infection. Hand-rearing infected young may be attempted but is difficult.

The incidence of mastitis can be reduced if nest boxes are maintained without rough edges to the entrance, which can traumatize the teats (breasts) when the doe jumps in and out of the nest box. The nest box should be sanitized before and after use.

Hutch burn is caused by wet and dirty hutch floors, by bladder irritation from calcium deposits, or by constant urine dribbling because of poor bladder control. The area surrounding the anus and genital region becomes inflamed and irritated. This is followed by infection with disease-causing bacteria. Brownish crusts cover the area and drainage of blood or pus may occur. Keeping hutch floors clean and dry and applying an ointment recommended by your veterinarian speeds recovery.

Hutch burn is often confused with a bacterial disease called treponematosis (see above). Laboratory tests are required to distinguish between these diseases.

Female rabbits have a heavy fold of skin called a dewlap on the front of the neck. As the rabbit drinks, this skin may become wet and soggy, which leads to inflammation. Possible causes include dental malocclusion, open water crocks, and damp bedding. 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.

Watering systems with drinking valves generally prevent wet dewlaps. If open water receptacles are used, they should have small openings or be elevated.

Sore hocks, also called ulcerative pododermatitis, does not actually involve the hock (the ankle joint) but instead affects 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, followed by skin infection. 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 breeds such as the Rex, Flemish Giant, and Checkered Giant are 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 agents can be used to clean the sores. Topical and injected antibiotics are also used. X-ray images may be needed to check for bone involvement in severe cases. The rabbit must be removed from the cage or given a solid floor (board or mat) on which to sit or rest. Often, the feet are temporarily bandaged, and large amounts of clean, soft, paper-based bedding or fleece is added to the cage to decrease pressure on the bottom of the feet. Treatment is difficult and time-consuming. 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. Rabbits typically develop patchy areas of hair loss, initially on the head, which spread to other areas of the body. Patches may become dry, flaky, and red but are not generally itchy. 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. Rabbits that carry the fungus without showing any 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 USA, myxomatosis is restricted largely to coastal areas of California and Oregon. These areas correspond to the geographic distribution of the California brush rabbit, the reservoir of the infection. The virus is transmitted by mosquitoes, fleas, biting flies, and direct contact.

The first sign of disease is conjunctivitis (inflammation of the eye) that rapidly becomes more severe 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 eyelids, nose, lips, and ears become puffy, 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 discharge of pus from the nose, difficulty breathing, and coma. Death 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 genitals), 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 USA. 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 caused by a virus, are found in nature only in cottontails, although domestic rabbits can be infected by virus-containing material. Fibromas may be found in pet rabbits in areas where these tumors occur in wild rabbits and where pet rabbits have contact with insects and ticks that transmit disease.

The fibromas 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 rabbit oral papillomavirus, are small, gray-white lumps or warts on the bottom of the tongue or on the floor of the mouth. The second type, caused by cottontail (Shope) papillomavirus, is characterized by warts that form dry, thick skin projections 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.

Ear mites, rabbit

Ear mites are common in rabbits. These parasites irritate the lining of the ear and cause fluid and thick brown crusts to build up, creating an “ear canker.” Infested rabbits scratch and shake their head and ears. They lose weight and may develop infections that can damage the inner ear, reach the central nervous system, and result in head tilt or "wry neck" (a twisting of the neck to one side). Your veterinarian will treat the condition with injectable or topical medication. Although it is tempting to try to remove the crusts, doing so is painful and can cause severe bleeding. Crusts dry up and fall off after treatment with medication. 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 is weakened by age, illness, or stress. The mites may look like dandruff that moves when it is scraped from the skin onto a dark paper or background, leading to the nickname “walking dandruff." Transmission is by direct contact. A diagnosis can be made by looking at skin scrapings under a microscope. Fur mites may cause 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. Your veterinarian will treat with injectable or topical medications, but thorough environmental cleanup and disinfection is essential to prevent reinfection.

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, which is part of several products for treating fleas in dogs, should never be used in rabbits. Ask your veterinarian for a treatment recommendation if your rabbit has fleas.

Abscesses (pus-filled and inflamed sores) on the internal organs and below the skin, caused by Pasteurella bacteria or other types of bacteria, may not be apparent for long periods and then may suddenly rupture. When bucks penned together fight, their wounds often develop abscesses. Because a rabbit’s pus is thick and doesn’t drain well, their abscesses must be removed surgically and treated with antibiotics long term. 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 with water 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°F to 70°F (10°C to 21°C) and a relative humidity of 40% to 60%, with good ventilation. Wire cages are preferable to solid hutches. At temperatures higher than 80°F (27°C), rabbits are particularly prone to overheating. Therefore, above this temperature, outdoor rabbits should ideally be brought inside.

If you suspect that your rabbit has heat stroke, dampen its ears with cool water, place it in front of a fan, and take it immediately to your veterinarian or an emergency clinic.

Listeriosis, a bacterial infection of the blood that causes sudden death or abortion, is most common in does near the end of pregnancy. Dirty environmental conditions and stress may contribute to the disease. Signs may include loss of appetite, depression, and weight loss. Listeria monocytogenes, the bacterium that causes the disease, spreads via 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. The bacteria also can infect people, and up to 90% of human cases are linked to wild rabbit exposure. The bacteria are found widely in the south central United States. Tularemia 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 on postmortem examination (after death), such as signs of bacterial blood infection, spots on the liver, and liver and spleen enlargement. There is no effective treatment for infected rabbits. Tularemia is a reportable disease; your veterinarian is required to report suspected cases to public health authorities.

Encephalitozoonosis is a widespread protozoal infection of rabbits and occasionally of mice, guinea pigs, rats, and dogs. It causes kidney disease and also commonly affects the brain, causing neurologic signs such as head tilting, rolling or falling over sideways, seizures, and tremors of body parts. This contagious organism is spread from rabbit to rabbit by contact with infected urine and can be spread from mother rabbits to fetuses in the uterus. Your veterinarian can use laboratory tests to diagnose the disease. Along with anti-inflammatory medication, several anti-protozoal medications are available for treatment, but none is 100% effective. Prevention requires good sanitation.