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.
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.
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 had holes in the horizontal and vertical tubes originating on the main rectangular enclosure. 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 in of the house" (even for very 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 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 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 shouldn't 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 practical treatment Injured hamsters should be immediately examined by a veterinarian. Broken bones are very difficult to manage. Often an appliance (splint, etc.) to mobilize 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.
Sensitivity of Hamsters 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 injectable antibiotics can cause the problems described above, oral antibiotics are more often associated with them. Antibiotics 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.