Guinea pigs

Diseases of Ferrets, Rabbits, Guinea Pigs and Hamsters


Ferrets have become quite popular as pets, and for good reasons! These winsome mammals are intelligent, inquisitive and good-natured. A pet ferret may be expected to have a lifespan of between 5 and 8 years. Ferrets that are usually offered for sale in the pet trade have already been neutered (spayed or castrated) and descented (demusked). A ferret that is fed a good-quality diet and is cared for properly should remain healthy through middle age. Most ferret diseases occur as they get older, with a few notable exceptions.

1. ECE (Epizootic catarrhal enteritis) is usually a disease of adult ferrets. ECE is also called "green slime disease" since the most obvious clinical sign of this illness is green diarrhea. ECE is suspected to be caused by a virus. Adult ferrets become exposed by having an owner play with baby ferrets in a pet store, then returning home and handling their own adult ferrets. Young ferrets are rarely infected. The disease may also be introduced into the household when ferret owners bring home a new baby ferret. Within a week or two of exposure, exposed adults become listless and develop green, slimy feces. A ferret with ECE may have a decreased appetite and it may develop a fever.

Any ferret suspected of having ECE should be evaluated by a veterinarian who is familiar with ferrets. Since ECE is viral, there is no specific antiviral therapy available at this time. Most ferrets with ECE are dehydrated and will require fluid therapy. Often antibiotics are administered to prevent secondary infections, and antidiarrheals are usually given. It is very important for a sick ferret to continue eating, and if it will not eat, it may need to be gently force-fed, using a syringe or spoon. A ferret that is not eating will quickly develop liver damage (called hepatic lipidosis).

Most ferrets will recover from ECE within a few weeks. Some may require hospitalization and intensive care in order to recover. Rarely, a ferret will have diarrhea for months after infection, due to inflammation in the bowel, which may require treatment with anti-inflammatory drugs.

At this time, there is no vaccination to prevent ECE. If you have adult ferrets, it is best to not handle other ferrets, especially youngsters, and if you have an established family of ferrets, it is recommended that you not introduce a new young ferret.

2. Ferrets are prone to several different diseases that can cause problems of the digestive tract. They are true carnivores and should only be fed a good quality ferret diet (or if that is unavailable, good quality kitten or cat food). They cannot tolerate more than 4% fiber in the diet. If fed an inappropriate diet, they may develop gastrointestinal problems. Young ferrets are very curious and may accidentally eat portions of a toy or non-digestible items found around the house. This may result in a blockage that requires surgery.

Ferrets may harbor one of several types of bacteria that can cause gastritis (inflammation of the stomach) and, on occasion, ulcers. The most common bacteria is called Helicobacter. Ferrets with gastritis may vomit or have diarrhea. The stool may be black and tarry if the ulcer is bleeding. If untreated, ferrets with gastritis may lose weight and become dehydrated. Antibiotics are prescribed to treat gastritis, and other medications may be necessary, as well.

3. Parasites can be a problem with some ferrets. They may suffer from flea infestation which can be controlled with prescription medication from your veterinarian. They may occasionally have ear mites, which causes a brown, odiferous exudate in the ear canals. Ferrets with ear mites often scratch at their ears excessively. Ferrets may also acquire heartworms from the bite of an infected mosquito. For ferrets at risk, heartworm preventative medication that is administered daily or monthly, can be prescribed by a veterinarian.

4. Ferrets may develop endocrine disease which usually develops in middle age. One common disease is insulinoma. A tumor in the pancreas of the cells that produce insulin (the hormone that controls blood sugar levels) causes the problem. A ferret with an insulinoma will develop problems associated with low blood sugar. Early signs may include a glassy-eyed appearance and increased salivation. Often, the ferret is depressed and may not respond to external stimuli (such as petting it, lifting it up or calling its name). The ferret may collapse and then recover after a period of time. Another presentation of this disease is a gradual onset of weakness that occurs over a period of weeks or months. The ferret may develop intermittent periods of weakness and a wobbly gait, with the hind legs being obviously affected. In between episodes, the ferret may appear perfectly fine. Diagnosis is made through blood testing, ultrasound or surgery. Treatment of insulinoma is by medication or surgery.

Another endocrine disease is caused by a tumor of the adrenal gland. This gland is situated near the top of the kidney, one on each side, near the corresponding kidney. Tumor of the adrenal gland often causes a bizarre group of symptoms including symmetrical hair loss or thinning, especially over the back, hips, rump, tail and thighs. The ferret may appear very itchy where the hair is missing. The hair loss is often progressive and typically begins in the late winter or early spring and it may continue until the ferret is bald, or the hair may regrow in the fall, only to begin another hair loss cycle in the following winter or spring. Over 90% of the ferrets with adrenal disease show some hair loss. In all species, the adrenal glands produce hormones, and the predominant hormones are in the corticosteroid group. However, adrenal tumors in ferrets produce excessive amounts of sex hormones, and not corticosteroids. Many spayed females with adrenal disease have an enlarged vulva (external genitalia). Males with adrenal disease often develop partial or complete blockage of the urinary tract and may have difficulty urinating.

To diagnose adrenal disease, the veterinarian may be able to palpate (feel) an enlarged gland. Radiographs (x-rays) and ultrasound may be necessary. A blood panel that measures several different sex hormones is the best way to diagnose adrenal disease in ferrets. Adrenal disease can be managed medically, however surgical removal of the diseased gland is the preferred method of treatment.

5. Lymphoma is another disease often diagnosed in ferrets. This may occur in young ferrets (as young as 4 months of age), or it may be diagnosed in adult ferrets, as well. This disease is highly variable and may occur acutely or chronically. The ferret may act lethargic, weak and it may lose weight. the lymph nodes may be enlarged. The disease may affect almost any organ system, so signs will vary depending on which organs are being damaged. This disease may be diagnosed through blood tests, radiographs, biopsy of a lymph node, spleen, liver or bone marrow. Treatment using chemotherapy may bring on remission of the disease for varying periods of time. Surgical removal of any large, solitary masses may be helpful.



Rabbits are popular pets. They are not in the rodent family, but have been assigned their own special group, the lagomorphs. With a proper diet and good husbandry, they can live for 5-6 years or more. Rabbits should eat primarily timothy hay, and they may be offered timothy hay-based pellets and small amounts of vegetables (sprouts, beet greens, carrots and carrot tops, green peppers, parsley, romaine, kale, outer cabbage leaves, pea pods, squash and dandelion leaves), and small amounts of high-fiber fruit (apple, peach plum, pear, melon, raspberry papaya, strawberry and pineapple).

1. Most people have heard of the rabbit disease called snuffles. Snuffles is often one clinical manifestation of the group of diseases caused by the bacterial organism called Pasteurella. Many clinically normal rabbits are harboring the Pasteurella organism and the incidence of disease increases as the rabbit ages. The Pasteurella bacterium usually causes respiratory disease, but it may also cause ear infections, pneumonia, heart problems, abscesses, genital infections, eye problems, septicemia and chronic infections. Rabbits with snuffles often have bouts of sneezng, with a yellowish, thick discharge, and due to constant grooming, the fur around the nostrils and on the insides of the forepaws will be stained with yellowish mucus. Rabbits may make sonorous noises. If the eyes are affected, the lids may have a crusty discharge and the eyes may tear excessively. Diagnosis may be made by several different testing methods. Other bacterial organisms may cause the same clinical signs as snuffles, so diagnosis by DNA PCR technology, culturing, blood titers or a combination of these is important to ascertain the bacterium causing the problems, in order to correctly treat it.

Since snuffles is caused by a bacterium, there is a slight chance that the Pasteurella organism can be passed to a person handling the rabbit, usually through a scratch or bite. However, most healthy people will not acquire this infection due to their immune system's ability to fight off this bacterium. If you suspect that you may have acquired an infection from a pet, it is always best to contact your human physician for advice.

Treatment with appropriate antibiotics (usually given orally as a liquid or pill, but occasionally by injection) may result in improvement of clinical signs, but it is unlikely that the bacteria will be completely removed from an infected rabbit, and it will likely relapse from time to time, requiring additional treatment.

2. Ear mites are frequently encountered in rabbits. Ear mites cause severe inflammation and crusting in the ears which results in a very painful condition. Affected rabbits scratch at the ears and shake their heads, which may cause additional trauma to the ears. In a weakened, ill animal, the mites can spread to other areas of the body, especially the area under the tail, the legs and feet. The mites may be identified with the naked eye, with the aid of magnification or by examination of a smear of ear debris under the microscope. Treatment should be administered by a veterinarian. The most common medication used is ivermectin, given by injection every 2 weeks for at least 3 treatments. The ears should NOT be cleaned out since they are very painful and will bleed excessively. All rabbits that have been in contact with the infested rabbit should be examined and treated if necessary. The bedding should be changed and the entire cage disinfected to prevent reinfestation.

3. Hairballs (also called wool-block or trichobezoars) may occur in rabbits from fur chewing, and are more commonly seen in rabbits being fed a high carbohydrate, low fiber diet that grooms excessively. Rabbits with hairballs have decreased or no appetite, scant stool production (or no stool at all) and a large stomach (filled with hair and stomach contents). The vet may be able to feel a large, doughy mass in the stomach. Radiographs may be helpful. Large amounts of gas may be found in the stomach. Treatment should consist of giving the rabbit oral fluids and often sub-cutaneous fluids, as well. The rabbit should be force-fed fluids such as fruit juice, water and vegetable purees (fruit and vegetable baby foods). Medication to stimulate stomach contractions is often helpful. Protein-digesting enzymes such as bromelain and papain found in pineappple have been used for treatment. If necessary, antibiotics will be prescribed. Rarely, surgery may be required to remove a hard, dry mass in the stomach that doesn't respond to medical treatment.

4. Fractured bones can occur in a rabbit. A rabbit should always have its hind end supported when it is lifted up or carried. A frightened rabbit may kick the hind legs when being picked up, and if the back end isn't supported, this may result in a broken back, or less commonly, a dislocated back. Depending on the severity of the injury, the rabbit may become paralyzed in the hind end, it may suffer from loss of bowel and bladder control and it may lose sensation in the hind end. Occasionally, bones of the limb may break from a fall or from being stepped on. Physical exam and radiographs will confirm the diagnosis. Treatment may be attempted with splints, cage rest and medications, or surgery may be necessary.

5. Dental problems usually occur from teeth that don't line up correctly (this is called malocclusion). The teeth of rabbits are different than those of dogs, cats and people in that they grow continually throughout the animal's life. If the teeth aren't aligned properly, they will not wear down at the correct rate, resulting in weight loss due to problems eating. This is not just a problem of the front incisors, as the back molars can overgrow as well. Routine examination of every rabbit should include examination of all the teeth. Overgrown teeth can be trimmed using a variety of drills or cutters. Teeth will need to be trimmed on a regular schedule in order for a rabbit to eat properly. Removal of overgrown teeth may be elected, as this provides a permanent solution to the problem. Extractions must be performed under general anesthesia. Rarely, a portion of the tooth root may be inadvertently left behind, allowing the tooth to regrow. Re-extraction may be attempted once the tooth has regrown to a suitable length.


Guinea pigs

Guinea pigs are members of the rodent family. They are good natured pets suitable for children. Guinea pigs are easy to care for, and with a good diet and husbandry, they may live for 4-8 years (the average is 5 years in the pet home). Guinea pigs should be fed a high quality guinea pig pelleted diet. The feed should be purchased frequently to ensure that it is fresh. These creatures are unique in that they require an outside source of vitamin C, which may be offered as a supplement in the drinking water or in foods high in vitamin C (such as 1/4 orange daily or a small handful of cabbage or kale). Treats should be limited to 1-2 tbsp. of timothy hay, alfalfa cubes, green vegetables, carrot tops and apple).

1. Guinea pigs, also called cavies, may suffer from vitamin C deficiency (also called scorbutus or scurvy). Signs of vitamin C deficiency include hemorrhage in the joints, gums, loose teeth, malocclusion, rough hair coat, loss of appetite, diarrhea, teeth grinding and vocalizations from pain, delayed wound healing, lameness and increased susceptibility to bacterial infections. Fractures of bones may spontaneously occur. Young, growing animals are most susceptible to scurvy. Diagnosis is usually made based on evaluation of the diet and the clinical signs, although a blood test to measure vitamin C levels is available. Most often, response to supplementation with vitamin C is the best way to confirm the diagnosis. Many ill guinea pigs will be suffering from subclinical scurvy, and will benefit from administration of supplemental vitamin C given by injection or orally.

2. Guinea pigs are prone to bladder stones (also called urolithiasis or urinary calculi). Females may develop bacterial bladder infection that leads to stone formation in the bladder. In some cases, a stone or stones can be palpated in the bladder by an experienced veterinarian, but often a radiograph may be necessary to diagnose this. In dogs and cats, it may be possible to dissolve a stone in the bladder by the administration of urinary acidifiers, but this generally won't work in guinea pigs. Antibiotics may be necessary to treat any infection, but surgery is usually required to remove stones. Unfortunately, there is little one can do to prevent stones from recurring (in dogs and cats, special diets can be given to prevent stones forming), and often repeated surgeries are necessary to remove stones as they form.

3. Female guinea pigs may suffer from cystic ovaries as they age. It is estimated that over 75% of female cavies between 1.5 and 5 years of age have them. The cysts, which develop spontaneously, can be of varied sizes, and there may be one or several, on one ovary or both. A breeding sow may show decreased fertility. Pet guinea pigs may develop bilaterally symmetrical hair loss over the trunk and flanks. Ovarian cysts can be diagnosed through ultrasound. Medical treatment with chorionic gonadotropin injections may be attempted, and cysts may be drained with ultrasound-guided needle aspiration, but these treatments will usually only result in temporary improvement and the cysts may return. Surgery to remove the affected ovaries is curative, and usually a complete ovariohysterectomy is performed (commonly called a "spay").

4. Guinea pigs may suffer from skin disease. A type of skin mite can cause severe disease, including intense itching, red, inflamed skin and hair loss. Often the skin is crusty and thickened, and it may have a bad odor. Lice may also infest cavies, also causing lesions, hair loss and rough hair coat. Diagnosis may be made by skin scrapings, biopsy of the skin or by the history and clinical signs. Some mites can temporarily infest humans. Treatment with medicated shampoos, dips safe for cats, pyrethrin-based flea powder or spray for cats or ivermectin (oral or injectable) can be administered by your vet. The environment should be thoroughly cleaned and disinfected as well.

Cavies can also become infected with ringworm, which is actually a fungal disease. The skin may appear crusty and itchy, and the hair loss pattern may be patchy. Ringworm can be cultured from lesions, or skin scrapings can be examined under the microscope. Treatment can be prescribed by your veterinarian using topical or oral medication.

5. Guinea pigs can suffer from heat stroke, which can be very serious, even fatal. Cavies have developed heat stroke at temperatures as low as 70-75 degrees F. They cannot tolerate high temperatures, especially if they have been housed indoors with air conditioning. Temperatures above 80-85 degrees F can be fatal, especially in non-acclimated cavies. Guinea pigs suffering from heat stroke salivate profusely in their attempt to lower their body temperature. The diagnosis of heat stroke can be made based on the history and clinical signs. The body temperature will be elevated above the normal rectal temperature of 101.5-103 degrees F. The cavy will have shallow, rapid breathing, pale gums and it will be unresponsive. This can rapidly progress to coma and death. If a guinea pig is discovered that is showing signs of heat stroke, it should receive immediate emergency care. Before to taking it to the vet it should be given a cool bath and placed on a towel wet with cool water for transportation to the vet. The vet will give additional emergency treatment, but the prognosis for recovery is very poor.



Rats are members of the rodent family, and despite the bad connotation that comes from wild rats, the domestic rat can make a delightful pet. Rats are bright and inquisitive and they rarely bite unless seriously provoked. Rats should be fed a commercial rodent pelleted diet (seed-based diets are often nutritionally inadequate). Treats are not recommended nor necessary. They may live for 2-3 1/2 years, with the record for longevity being 4 years.

1. Rats may suffer from infection with an organism called Mycoplasma. This primitive organism often causes respiratory disease in affected rats. They may sneeze and have discharge from the eyes and nose. With chronic infection, the rat may suffer from nosebleeds. This can progress to pneumonia. The Mycoplasma organism can also cause problems with the urogenital tract, and may cause abortion or embryonic death in pregnant females. The Mycoplasma infection may be complicated by other organisms, resulting in a mixed infection. Diagnosis may be made by culturing the organism, by clinical signs or by newer DNA testing. Treatment with antibiotics may cause the rat to improve clinically, but the infection is not eliminated, on most occasions. Nebulization therapy may help the rat's breathing.

Red tears are caused by a secretion of porphyrins (pigments) from a gland behind the eyes. The red tears occur more commonly with stress, and their discovery warrants a complete physical exam and testing of the affected pet rat.

2. Rats may develop skin infections from scratching skin due to fur mite infestation, or from scratching the skin over an inflamed salivary gland. Often skin infections are caused by the Staphylococcus bacterium. In addition to treating the fur mites with oral or injectable ivermectin (administered by a veterinarian) or by using topical powders or sprays, the toenails of the hind feet should be clipped to minimize skin trauma. Usually, only a topical antibiotic cream or ointment is all that is necessary to treat the skin infection.

3. Older rats may develop tumors of the mammary glands. Spayed rats are much less likely to develop these types of tumors, however most pet owners do not have elective surgery performed to spay pet rats. Tumors can occur in both male and female rats. Mastectomy surgery provides the best chance for complete recovery, provided that the tumor is not malignant, and has not spread to other locations.

4. Overgrowth of incisiors is common in rats. Like the rabbit, the teeth of the rat continue to grow throughout life. If incisiors overgrow, they can actually grow into the nasal cavity. Overgrown teeth can be trimmed by a veterinarian, but they may need to be trimmed on a regular schedule. A permanent solution is to have a veterinarian extract incisors under general anesthesia. Rats need to chew to keep the teeth at a normal length (unless the teeth are misaligned, causing the overgrowth).

5. Older rats may suffer from a kidney disease called chronic progressive nephrosis (CPN). A urinalysis will show elevated protein levels in the urine. Rats with kidney disease may show signs of increased thirst and urination, weight loss and rough hair coat. Feeding a special diet may help slow the course of the disease in affected rats.


This list of diseases is not a complete discussion of the many illnesses that can occur in ferrets, rabbits, hamsters and guinea pigs. This is meant to give the pet owner information regarding some of the more common diseases in these species. If you suspect that your pet is ill, it is vital that you seek the help of a veterinarian experienced with the type of animal that you own. It can be very dangerous to attempt to diagnose disease yourself and to attempt treatment, since many diseases appear alike, and in most cases, drugs must be dosed very carefully based on precise body weight (in grams or kilograms). If your pet is ill, with the help of a good veterinarian, your pet may be restored to good health or at least kept comfortable. Providing veterinary care when necessary is a vital part of keeping your pet healthy so that it can live out its normal lifespan.

Copyright 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
All Rights Reserved

Printer Friendly Page