Health Problems in Rodents

Rodents have several unique problems. Understanding these problems will allow you to better care for your pet and minimize future health care problems.



A common concern among owners of pet rodents is the possibility of contracting rabies if bitten by their pets. While any mammal (warm-blooded animal that nurses its young with milk) can contract and transmit rabies, the likelihood of this happening with a pet rodent is almost non-existent, as rodents (especially those housed inside, away from other animals) rarely get rabies. Despite this, no pet rodent should be left outside unattended where contact with rabid animals, such as foxes, racoons, skunk, and bats, is more likely. Nonetheless, rodent bites can become easily infected, so you should contact your doctor immediately if you are bitten by your pet.



Many rodents will chew or barber their own hair or the hair of a cagemate. Barbered hair will appear as an area of thin hair in which each strand has a short, bristle or brush-cut appearance or feel to it. Barbering is often caused by stress in the form of overcrowding, fighting, or boredom. Separating the animals and providing them with toys for enrichment may help the problem.


Foot Necrosis

This problem is caused by the fine fiber or thread nesting material (or bedding), commonly available in pet stores, wrapping around toes or feet and cutting off circulation. As the pets play with the material, the fine thread gets wrapped around a toe, foot, or leg, and within hours the body part swells and begins turning red and then purple to black. If not caught immediately, the swelling progresses to necrosis or death of the affected toe or limb. In some animals, amputation is curative. To prevent this condition, DO NOT USE this fine bedding or nesting material. Shredded tissue or paper is much safer and works perfectly as nesting material.


Vitamin C Deficiency (Scurvy)

Guinea pigs, like people, do not make vitamin C in their bodies, therefore vitamin C is an essential nutrient in their diets. The majority of other animals can produce their own vitamin C from their intestinal bacteria, but guinea pigs and humans are unable to do this. Vitamin C is vital in the normal development and maintenance of skin, joints, and mucosal surfaces like gums. It is also important in the healing of wounds. As well as predisposing your guinea pig to skin problems, a lack of vitamin C makes the body more prone to other diseases. A guinea pig that has a rough hair coat, decreased appetite, diarrhea, reluctance to walk, seems painful, has swollen feet or joints and hemorrhages and ulcers on its gums or skin, is likely to be deficient in vitamin C.

"Guinea pigs, like people, do not make vitamin C in their bodies."

Guinea pigs need 50 mg vitamin C per day. While vitamin C is readily available from fresh fruit and colored vegetables, such as bell peppers, guinea pigs need more vitamin C than fresh vegetables contain. Be sure that you supplement your guinea pig with a vitamin C tablet by mouth daily, and that the guinea pig pellets contain added vitamin C. Because this vitamin breaks down or oxidizes quickly, pellets should be used up or replaced within 90 days of the date of manufacture.

Vitamin C supplements should be given to guinea pigs directly by mouth, rather than in drinking water, because the vitamin breaks down rapidly in water and loses its potency.


Hyperthermia (Heat Stroke)

All pet rodents, but especially guinea pigs and chinchillas, are very susceptible to heat stroke from high ambient temperatures. As a rule, the cage should be well ventilated, with an environmental temperature no higher than 80°F (27°C) and a humidity below 70%. Signs of heat stroke include panting, salivating, weakness, convulsions, and refusal to move. Treatment involves immediately cooling the pet with cool water baths or sprays and seeking prompt veterinary care. Hyperthermia can be life-threatening, so veterinary care must be sought as soon as possible.


Antibiotic Toxicity

Pet rodents are extremely sensitive to certain types of antibiotics. Some antibiotics, especially penicillin and similar drugs, upset the normal bacteria that live in rodents’ gastrointestinal tracts and favor toxin-producing bacteria that release substances that can be fatal to rodents. This can be true whether the antibiotics are given orally, injected, or topically (on the skin). Antibiotics that should not be given to rodents include penicillin and related drugs, bacitracin, erythromycin, lincomycin, tylosin, procaine additives, and streptomycin. There are some excellent oral and injectable antibiotics that are safe to use in rodents, and a rodent-savvy veterinarian will know which ones are safe and which are not.

"Pet rodents are extremely sensitive to certain types of antibiotics."

Guinea pig owners should NEVER use antibiotics in or on their pets without first consulting a rodent-savvy veterinarian.


Chromodacryorrhea (Red Tears)

Red tears are seen in mice, gerbils, and most often, in rats.  The rodent will appear to have dried blood around its eyes, nostrils, and even on the inside of its forearms (from wiping its face with its front legs). This is not dried blood, but a red pigment called porphyrin that is made from a specialized tear gland called the Harderian gland and that gives the tears a reddish or rusty red color. This gland increases its secretions in response to stress and illness. The increased tear production may overflow the eyes and stain the surrounding fur. Tears naturally drain through the tear duct into the nasal passages; some of this drainage comes out the nose, where it may form a dried red discharge. Rodent owners often call their veterinarians because they mistakenly think their pets are bleeding from their eyes and/or noses.

Chromodacryorrhea can occur as a result of disease or as a sign of environmental or social stress. Often it is hard to tell what is actually causing the problem. A veterinarian familiar with rodents should examine your pet, treat any specific disease or illness, and try to identify and help you eliminate the stresses in your pet's life.


Diarrhea (Wet Tail)

The most serious intestinal disease of young hamsters is commonly referred to as wet tail. Wet tail simply means diarrhea, and it can have several different causes in rodents including anything that disturbs the natural bacterial balance of the intestines, such as infections with different bacteria, parasites, or viruses. More commonly, 3 to 10-week-old hamsters are affected and show signs of lethargy, loss of appetite, unkempt hair coat, watery or bloody diarrhea, and a soiled tail and rectum.

"The most serious intestinal disease of young hamsters is commonly referred to as wet tail."

As diarrhea can lead to dehydration, weight loss, and weakness, diarrhea in rodents requires immediate treatment and supportive care including fluid therapy, antibiotics, and if the animal is severely debilitated, hospitalization is required. Animals may die even with early, aggressive treatment. Any hamster with diarrhea must be seen by a veterinarian as soon as possible.



Fractures of the legs are very common and usually result from injuries sustained on exercise wheels (typically those with slotted bottoms in which feet can get caught) or from mishandling or falls.

"All handling by children should be supervised, and only solid-bottom exercise wheels should be used in the cage."

Mild fractures in which the broken bones are still aligned (non-displaced) may heal on their own. Severe injuries involving displaced fracture fragments, as seen on X-rays, may require surgical pinning of the fracture, splinting, amputation of the leg, or in very rare cases, euthanasia. All handling by children should be supervised, and only solid-bottom exercise wheels should be used in the cage.


Staphylococcal Dermatitis

A bacterial skin infection, often caused by infection with Staphylococcus bacteria, can occur on the muzzle and nose of gerbils. It is seen as areas of hair loss and moist skin (often due to the simultaneous presence of chromodacryorrhea, as described above). Bacterial infection is often secondary to other causes, including mange (parasites) or skin trauma from constant digging or burrowing. Treatment involves the use of antibiotics to eliminate the secondary bacterial skin infection, as well as treating the primary cause.



The gerbil is unique among rodents in that spontaneous, epileptic-type seizures can occur, often after handling the pet. Most gerbils do not require medication for the seizures. Guinea pigs with severe skin mite infections may also experience seizures as a result of the mites burrowing beneath their skin and causing extreme itchiness. Rodents with seizures should be examined by a veterinarian as soon as possible.

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