RECOGNIZING DISEASE IN HAMSTERS Because hamsters are very small, nocturnal (night- active) and not closely observed, the early signs of illness are frequently overlooked or not noted at all. Hamster owners must be constantly vigilant for signs of illness and must seek immediate veterinary assistance when illness is suspected.

Sick hamsters often become irritable and frequently bite. They are usually reluctant to move about and walk stiffly when forced to do so. Their eyes often look dull and sunken, and frequently have a discharge. Sick hamsters often stop eating or greatly reduce their intake of food. Consequently, weight loss is a common sign (not necessarily an easy one to recognize) of illness in hamsters. Fluid losses from diarrhea also may cause marked weight loss.

Sudden intestinal disease (with accompanying diarrhea) is the most common illness of hamsters, especially among those being weaned or recently weaned. If the serious accompanying dehydration is not recognized immediately and corrected with appropriate fluid therapy at the direction of a veterinarian, death is probable. As soon as diarrhea is observed, we recommend using a product such as Gatorade or Pedialyte to add both electrolytes (salt) and sugar for energy as a water source.

CONDITIONS REQUIRING VETERINARY ATTENTION:

Teeth Problems:

The incisor (front, gnawing) teeth grow continuously for the life of the hamster (this is true for all rodents). They receive continuous wear as the uppers and lowers contact each other, preventing overgrowth. Misalignment of either the upper or lower incisors because of previous injury, abscess formation or malnutrition may result in overgrowth of one or more of the teeth.

Overgrown incisor teeth usually cause serious injury to the roof of the mouth. Sometimes the lower incisors actually grow through the roof of the mouth and into the nasal cavity!

Initial signs of this problem are inappetence and drooling. Total lack of eating, weight loss, and a foul odor from the mouth may be noted later. These signs often are completely overlooked. A veterinarian must carefully trim the overgrown incisors and extract them from the roof of the mouth. Antibiotics are prescribed because of the high probability of infection following this type of injury. Periodic trimming of the incisors is usually necessary for the remainder of the hamster’s life.

Some popular hamster houses made of plastic have holes in the horizontal and vertical tubes originating from the main rectangular enclosure. In the past, hamsters frequently caught and broke their incisors in these holes in the plastic. The holes have since been made smaller by the manufacturer, and this injury is seen less frequently now.

Trauma:

Hamsters are easily injured. They are frequently dropped while being handled (especially by children), or after they bite. Pet hamsters allowed “free run of the house” (even for short periods) are often stepped on or kicked and seriously injured or killed. Hamsters are frequently injured while inside an “exercise ball”. This is a clear plastic sphere that is propelled along the floor by the action of the hamster running inside it. Injuries occur when a person accidentally kicks the ball or when it falls down a flight of stairs. Hamsters often perish when they are forgotten and left in these devices without food and water. In spite of the clever design and obvious benefits of this device, hamster owners must continually supervise its use. Parents must be made aware by their children that it is in use. Above all, hamsters should not be forgotten while inside these devices.

Trauma may result in broken bones and/or serious internal injuries or death. A fall of over just a foot or more may result in a broken back, for which there is no practical treatment. Injured hamsters should be immediately examined by a veterinarian. Broken bones are very difficult to manage. Often an appliance (splint, etc.) to immobilize the broken bone will not be applied because of the sometimes greater problems they impose on the broken limb. The veterinarian will determine the best course of action in each situation.

Bladder Stones:

Hamsters are susceptible to formation of stones within the urinary tract. The bladder is the only location within the urinary tract in which stones would likely be detected upon physical examination by a veterinarian. Signs of bladder stones may or may not be detected by hamster owners and are usually associated with infection within the urinary tract, frequent urination, straining on urination, blood in the urine, increased water consumption, listlessness and inappetence.

An experienced veterinarian may be able to remove the stones. This is accompanied by appropriate antibiotic therapy. Dietary management to help dissolve the urinary stones and prevent their recurrence is not practical with hamsters.

Cancer:

Cancer is very common in pet hamsters. The incidence increases with age (as is the case with most animals) and is higher among females than males because of the variety of cancers that involve the female reproductive tract. Tumors of hamsters may be benign or malignant. Hamsters are vulnerable to an unusually large number and variety of benign cancers.

Cancers involving hormone-producing organs (such as the thyroid and adrenal glands) are among the most common tumors found in hamsters. These cancers cause hormone imbalances, hair loss and changes in behavior, as well as other significant signs. Veterinarians can often perform surgery to completely remove small external tumors.

Internal tumors, however, are much more difficult to diagnose and remove. The small size of the patient, the even smaller size of the organ(s) involved, the sometimes inaccessibility of the tumor and the expense involved are some of the reasons why an owner of a pet hamster might elect euthanasia (putting the pet to sleep) or do nothing and allowing the hamster to live out its life instead of surgery in these situations.

Lack of Food and Water:

Partial or total neglect of hamsters by their owners is an unfortunate but common problem. Neglectful owners fail to provide adequate supplies of food and water for their pets, and are unaware of any medical problems. Potentially serious dehydration, starvation, stomach ulcers, eating of bedding material, and even cannibalism have all been reported as a result of food and/or water deprivation.

Sipper tubes often become clogged or continually contact bedding material, thereby draining the water bottles to which they are attached. Water bottles and their delivery tubes must be checked constantly for these problems.

Parents must set a “good example” for their children and teach them a routine of care and maintenance of their pet hamster. Careful observation and vigilant attention to their hamster’s every need should be emphasized. Neglect to any degree is intolerable and always results in some detriment to the hamsters.

Abscesses:

Abscesses are most often caused by bite wounds from fighting. These wounds become infected, forming abscesses that appear as firm, painful lumps under the skin. Abscesses from injuries other than bite wounds may be indistinguishable from those that result from fighting. Abscesses of one or both cheek pouches are also very common among pet hamsters. These commonly result from penetrating wounds to the lining of the pouch caused by harsh foods or bedding material. It may be very difficult for you to know whether a swelling in the area of the cheek pouch is an abscess or simply food or bedding being temporarily stored within the pouch.

Generally speaking, the swelling resulting from stored food or bedding disappears when the animal empties its cheek pouch. If an abscess is detected or suspected, the abscess must be opened and the pus drained or removed by a veterinarian. An appropriate antibiotic also will be prescribed. Furthermore, the underlying cause(s) for the abscess must be eliminated, if possible.

Wet Tail (Proliferative Ileitis):

The most serious intestinal disease of hamsters is “wet tail”. The bacterium suspected of causing this disease is called Camphlobacter, which can also cause intestinal disease in swine, dogs, ferrets, primates and other animals. This disease most often afflicts hamsters of weaning age (3-6 weeks old), but hamsters of all ages are susceptible. Since weanling hamsters and those slightly older are commonly sold in pet stores, wet tail is a fairly common disease among recently acquired hamsters.

Long-haired “teddy bear” hamsters are highly susceptible to wet tail. Signs include lethargy, inappetence, unkempt haircoat, sunken, dull eyes, increased irritability, hunched posture, very fluidy diarrhea, and a wet, soiled anal area and tail. Blood from the rectum and protrusion of the rectal lining (prolapse) may be noted in particularly serious cases. Hamsters with wet tail must be immediately examined and evaluated by a veterinarian.

Fluid replacement, oral antidiarrheal medication, and antibiotics will be given, along with supportive care to keep the patient warm, clean, comfortable and well nourished. Treatment is often unrewarding, and death may occur as soon as 48 hours after the onset of initial signs. This disease is not transmissible to people.

Salmonellosis:

Several species of the bacterium, Salmonella, can cause serious intestinal disease (salmonellosis) in hamsters under certain circumstances. Salmonellosis is transmissible to and equally serious in people. The bacterium is usually acquired by eating food contaminated with the organism. Pet hamsters established in homes would most likely become infected via this route. For this reason, fresh fruits and vegetables must be thoroughly washed before they are offered to hamsters. Newly purchased pet hamsters may harbor the Salmonella organism, having acquired it from the colony into which they were born.

Salmonellosis in hamsters may manifest itself as sudden illness that often is fatal or as a more long-standing disease that causes weight loss.

Salmonellosis can be diagnosed on stool culture by a veterinarian. Antibiotic treatment of the disease may or may not be recommended by the veterinarian, depending upon the public health implications. Euthanasia (putting the patient to sleep) would be recommended if treatment is not undertaken.

Rabies:

The subject of rabies inevitably comes up whenever an individual is bitten by a hamster and because hamster bites are so common. Hamsters are not natural hosts of this virus. Therefore, the only way that a hamster could become infected with the rabies virus is to become exposed to infected saliva from a natural host of the virus (skunk, fox, bat, etc.). This is highly unlikely, since hamsters are almost exclusively indoor pets.

Lymphocytic Choriomeningitis:

This viral disease can be transmitted from hamsters to people. A large number of cases in 1974 and 1975 were traced to a common infected hamster colony. Signs of this disease in people include recurrent fever, headache, fatigue, muscle aches, sore throats, rash and arthritis. The natural host in the wild for the causative virus is the rodent population. Hamsters would most likely acquire their infection from this source. Because hamsters are almost exclusively indoor pets, they are unlikely to become infected with the virus.

Hamster owners must, however, restrict contact between their pets and orphaned wild rodents that have been adopted.

Demodectic Mange:

Demodectic mange, a common external parasite problem of hamsters, is caused by mites that reside within the hair follicles and certain glands of the skin. The mites cause dry, scaly skin and significant hair loss, especially over the back. This disease is rarely a problem by itself and is frequently associated with long- standing, debilitating diseases, such as those involving the kidneys. Hamsters exhibiting hair loss should be examined by a veterinarian as soon as possible. The doctor will do a skin scraping and examine it under the microscope. The presence of mites in the scraping confirms the diagnosis. This disease can be treated, but the patient may have an underlying problem for which there is no practical treatment or cure.

Intestinal Parasites:

Hamsters frequently harbor tapeworms within their small intestines. Heavy infections may cause weight loss. Lighter infections usually go undetected unless pieces of the worms pass out of the hamster’s anus or appear in the feces.

People can become infected with the same organism. Tapeworms can be transmitted to uninfected hamsters (or people) when feces harboring tapeworm eggs are inadvertently ingested. This underscores the importance of restricting access to hamsters and their enclosures by very young children. All such encounters should be carefully monitored.

Hamster owners suspicious of this parasite problem should submit a fecal sample to a veterinarian for analysis. The presence of tapeworm eggs in the sample (noted microscopically) confirms the diagnosis. Treatment can be instituted by the veterinarian.

Pinworms are a less common intestinal parasitism of hamsters. These extremely tiny worms reside within the large intestines and usually cause no signs at all. Pinworm infections can be diagnosed by a veterinarian by microscopic examination of the feces. Pinworm eggs passing from the anus of the hamster sometimes cause intense itching in this area. A veterinarian may be able to detect the presence of pinworm eggs by pressing cellophane tape to this area and examining it under the microscope. Pinworms of hamsters do not cause disease in people.

DISEASE SUSCEPTIBILITY:

Hamsters tend to be affected by relatively few naturally occurring diseases. Their susceptibility, however, to a host of infectious diseases of other animals, including people, and the ease with which these diseases can be transmitted to hamsters have made them very popular laboratory animals for biomedical research.

“Teddy bear” hamsters and other genetic varieties tend to be much more susceptible to disease and sensitive to antibiotics and other drugs than golden hamsters.

SENSITIVITY OF HAMSTER TO CERTAIN ANTIBIOTICS:

Hamsters as a group are unusually sensitive to the potentially lethal effects of certain antibiotics, whether they are given orally or by injection. Potentially harmful antibiotics include ampicillin,penicillin, erythromycin, lincomycin and streptomycin.

The major way in which certain antibiotics cause reactions is by altering the normal microbial balance within the gastrointestinal tract. Once the normal intestinal microfloral balance has been upset, certain bacteria multiply to abnormally large numbers. The multiplying bacteria produce harmful chemicals that can have lethal effects. Certain antibiotics (streptomycin, dihydrostreptomycin) are directly toxic and do not alter the normal microbial balance within the gastrointestinal tract. These antibiotics should never be used in hamsters.

Though injectible antibiotics can cause the problems described above, oral antibiotics are more often associated with them. Anti-biotics should never be given to hamsters unless they are prescribed by a veterinarian. If oral or injectable antibiotics are prescribed, 1/2 cc (1/10 teaspoon) of plain, white yogurt should be given orally to the treated hamster morning and evening for the duration of the antibiotic therapy and for an additional 5-7 days afterward. Yogurt helps replace those beneficial intestinal bacteria that often perish during antibiotic treatment.